Open Mining facility/operation GIS data Wondering if there is any GIS data available for mining operations in any places in the world.

I looked here but didn't find much:

https://catalog.data.gov/dataset?tags=mines
https://www.eia.gov/survey/#coal (these just look like a bunch of pdf forms, I didn't find any data).
https://pubs.er.usgs.gov/search?q=coal (such as this, which seems to have some data)

Am looking for open data not in PDF form, but if it only exists in PDF form then that would be okay. A better form would be CSV or shapefile.

For the US, there are several sources:

Mineral Resources Data System (MRDS)
MRDS is a collection of reports describing metallic and nonmetallic mineral resources throughout the world. Included are deposit name, location, commodity, deposit description, geologic characteristics, production, reserves, resources, and references. It subsumes the original MRDS and MAS/MILS.  As of 2011, USGS has ceased systematic updates to MRDS, and is working to create a new database, focused primarily on the conterminous US.

MAS/MILS:
This record is maintained in the National Geologic Map Database (NGMDB). The NGMDB is a Congressionally mandated national archive of geoscience maps, reports, and stratigraphic information, developed according to standards defined by the cooperators, i.e., the USGS and the Association of American State Geologists (AASG). Included in this system is a comprehensive set of publication citations, stratigraphic nomenclature, downloadable content, unpublished source information, and guidance on standards development. The NGMDB contains information on more than 90,000 maps and related geoscience reports published from the early 1800s to the present day, by more than 630 agencies, universities, associations, and private companies. For more information, please see http://ngmdb.usgs.gov/.

Data.Gov Mining related data set.

Digital Rockhound's companion
(Shameless plug for my software, not free though).
I created a new user interface to search MRDS and MAS/MILS databases.

For Canada:

Natural Resources Canada
This map depicts the location of Canada's principal producing mines for the given reference year. It includes locations for significant metallic, nonmetallic and industrial mineral mines (except clay products, peat, and most construction materials [most stone, sand and gravel]), coal mines, oil sands mines, and oil and gas fields across the country. Also depicted are the locations of significant metallurgical facilities across Canada. The data in this map are based on Natural Resources Canada's annual Map 900A – Principal mineral areas, producing mines, and oil and gas fields in Canada.

For Australia:

Australia's mineral resources and their global status
Australia's known resources of a wide range of mineral commodities are considerable in comparison with rates of production. Australia has the worlds largest economic demonstrated resources of bauxite, lead, zinc, silver, ilmenite, rutile, zircon, tantalum, and uranium. In addition, Australia is ranked in the top three countries in the world for economic demonstrated resources of brown coal, copper, cobalt, gold, iron ore, manganese ore, nickel , gem/near-gem and industrial diamond. Despite a high rate of discovery of significant new mineral deposits, particularly since the 1950s, there is considerable potential for discovery of further mineral deposits in Australia.

OZMin database (from site)
These data represent the OZMIN Oracle relational database containing geological and resource information for Australian mineral deposits. OZMIN has been compiled from published references and has been designed so that attribute information can be retrieved and analysed in relation to spatial data contained in geographic information systems. The national mineral deposits dataset contains data on over one thousand major and historically significant mineral deposits for 60 mineral commodities (including coal).

For United Kingdom:

MineralsUK
MineralsUK is the British Geological Survey (BGS) Centre for Sustainable Mineral Development. Facilitated by the BGS Minerals and Waste science programme, the Centre is a global leader in the compilation, provision and analysis of mineral statistics and the major UK national provider of spatial and statistical minerals information. We also carry out research in areas directly relevant to our user community, such as metallogenesis, land-use impacts of mineral extraction and geomaterials.


Would the atmosphere move rigidly with ground if you ignored wind? I know this sounds basic but I've wondered about this for a long time and I'm still confused.
In aviation, air speed is ground speed minus wind speed. If wind speed is zero, air speed equals ground speed.
But the earth is rotating 360 deg/day. At sea level this rotation imparts to you an eastward linear velocity of just over 400 m/s. The atmosphere is generally close to static at the surface, so the air moves at this speed also with the rest of us.
But what happens at 25 km above ground? If all winds magically disappeared, would you find the air move eastward at >400 m/s (with a tiny correction for the increased elevation of 6360 + 25 km instead of just 6360 km at sea level)?
This seems to be a requirement if air speed is to be calculated as ground speed + wind speed, since both speeds need to be relative to the same reference (the ground), so I want to say yes... but can someone confirm or dispute?
Thanks! And apologies for littering with basic questions like this. I should know this, but I don't.

I think you’re mixing up frames of reference a bit here.  That ~400 m/s speed of the surface is relative to an absolute, non-rotating frame of reference in which an observer sees the Earth as spinning on its axis.  In meteorology we typically use a rotating frame of reference that spins with the Earth, in which an observer sees the surface as moving at 0 m/s.  When we talk about wind, we talk about air motion relative to this rotating frame.  You essentially say this in different words:

… since both speeds need to be relative to the same reference (the ground)...

So, if all winds disappear (i.e., wind speed = 0 m/s) then all the air is moving with the rotating frame by definition.  There’s no meteorology or fluid dynamics invoked here, this just falls out from our chosen coordinate system and definition of “wind”, so it would be the same at 2 m or 25 km altitude.
NB Your definition of air speed changes from "minus" in the first para to "plus" in the last para; I've assumed that this was a typo.


What would be the effect of bringing seawater pipes to the Sahara desert? This is a childhood dream.

What would happen if pipes were installed (similar in principle to the Great Man-Made River, but for seawater) to continuously pump seawater into the Sahara desert.

Let's say that a precise desert location, with no known aquifer nor water table, was chosen to be an inner sea. And let's say that wildlife was negligible at that location. And that solar panels were installed to provide energy for the pumping of the water. And that the water was pumped at the surface of the Mediterranean sea and that precautions were taken not to greatly damage sea life.

How hard will it be to fill, say, a Nevada sized inner salty lake? And would that humidify the air enough that dew - falling to the ground each night - would somehow start a greening cycle?

What if a little mud was added to the water to precipitate into a bed that would retain the lake?

Is there any modification to this childish plan that would make it, at least, realizable?

This is an interesting question & I've been waiting to see what answers, if any, would be written.

One affect of creating such a lake would be a localized increase in humidity in the vicinity of the new lake, but nothing that would significantly increase rainfall.

By bringing in salty sea water there could be a risk of contaminating existing underground fresh water stores with salt, making such sources of water unusable.

Also, by being salty, the water could not be used irrigate crops. It may be possible to establish a fishery in the lake, bringing in salt water species of fish, but that would need to be carefully managed.

If for whatever reason, the supply of water was not maintained in the lake, eventually the lake would dry up leaving salt behind. This would then be blow around by the wind, contaminating the nearby land with salt and killing plants on that land and making the land unsuitable for any crops that may grow there now.

Also, if dew were to form, there is no control over how much dew would be created. Many factors come into play when dew forms: atmospheric pressure, wet and dry bulb temperatures, the amount of moisture in the air (humidity) and enthalpy of water vapour and liquid water.

Edit

Having thought about this some more, something similar to what you are proposing has already been done in Egypt, when the Suez Canal was completed and opened in 1869.

Within the canal system is Great Bitter Lake, which is a sea water lake. The presence of such a body of water for nearly 150 years has not increased the amount of moisture in the vicinity of the lake that would allow lush vegetation to grow.


What is caesium-137 used for in fracking? Caesium-137 is used in the fracking process. What is it used for?

Caesium-137 is not used in the fracking process.

Caesium-137 is used as a source of gamma-rays in some logging tools, most notably the density tool (one example), and some other instruments such as flowmeters. This is what the story you linked to is about. Logging tools are used after drilling to measure the properties of the rocks in the borehole, and thereby calibrate geological models of the subsurface. These sources are valuable, and should be secured and only handled by trained engineers. The caesium is completely enclosed in the tool, and none is left in the subsurface, unless something goes badly wrong with the logging process and a tool is lost.

Caesium-133, the naturally-occurring non-radioactive isotope of caesium, is sometimes used in drilling and fracking fluids in the form of caesium formate brine. Its high density (ca. 2300 kg/m³) improves drilling efficiency and rig safety, and assists with pressure build-up for induced fracturing. It's still pretty valuable stuff, so companies often rent it, retrieving as much as possible (5–15% losses are common, however) and paying only for what they use. Cabot is one vendor of such brines.


Comparing Pros and Cons of SWAT and HSPF To model hydrology in a watershed, two of the most famous and widely used distributed models are SWAT and HSPF. I have some good understanding of HPSF, but I don't know when and why should one prefer one over the other. HSPF can simulate with a timestep of 1 minute. I have already heard that SWAT is mostly used for agricultural areas. What I want to know that what is the basic difference between these two models in terms of the processes they model?

This is a broad question, the best way to compare the models is to go through the manuals and compare the process algorithms to see how the various hydrologic processes are handled. There are other considerations as well, including:

what environment/watershed are you modelling? How large, how urbanized, what type of soils/environment/precipitation vs evapotranspiration, how important are snow processes, etc., and compare that to what the models were made for
what is the purpose of your modelling? Your choice of model will be different if you are looking at water balance vs flood forecasting vs water quality estimates
what data do you have available? Some models are more intensive with data requirements than others, and if you only have daily precipitation and temperature (as is typical) than that will restrict some model types
what level of accuracy do you need? The timestep options in the models will make a difference

That being said, generally my understanding from a broad perspective is that:
- HSPF is a more detailed hydrologic model with larger data requirements for input forcings, and has also a more comprehensive process library with respect to water quality
- SWAT as you said was developed for agricultural regions, has less strict data requirements and also some ability to model water quality parameters (though less detailed than HSPF)

Depending on the purpose of your modelling, you may want to consider:

starting with a simpler model, such as GR4J, just to get the ball rolling before investing more time into complex models, particularly if just need simple answers from the model
using a flexible model where the processes can be modified on the fly and you are not committed to a particular set of algorithms when you choose the modelling framework, e.g. the Raven hydrologic modelling framework

Hope that helps!


How are Benagil caves formed? The Benagil caves are really impressive. How are they formed though? What makes that perfect domed shape and how is that hole in the ceiling created?

How are they formed? Erosion.

Long version: The rock/cliff the cave is set in possesses different hard/softness. Some parts of it are more prone to erosion than others.

Erosion comes in the form of waves and tides, washing and battering at the base of the cliff, nibbling away the soft parts of the rock quicker. Some chunks break off, rolling in the turf, bashing away at the cliff even more. Cracks form, get washed out and bigger and finally the cave forms. As is gets deeper and larger, rainwater might drip through the roof, adding to the erosion effects. Chunks to the roof start to fall down, and finally a part of the roof collapses. Your cave now has a hole to the sky.


Crickets found in Wales? Can we find crickets in Northern Wales? If no, what other insects found in Northern Wales make a chirping sound like that of crickets?

If this isn't an appropriate question for this thread, please migrate it.

There are crickets species living in Wales (Reference)

Field Grasshopper

Green Grasshopper

Meadow Grasshopper

Roesel's Bush-cricket

Oak Bush-cricket

Speckled Bush-cricket

Mottled Grasshopper
and even if a species is not common in this part of the UK it might be brought there e.g. as a secret passanger in a car.


High resolution global land use projections I am looking for global land use projections for a large scale hydrological analysis. The most widely used datasets are the LUH (v1) Products used for CMIP5 based on Hurtt et al 2011. These products have been recently updated for the preparation of the CMIP6 climate experiments (LUH v2).

LUH v1 products are available at a spatial resolution of 0.5 degrees. I am looking for something a little more detailed.

I am aware of a downscaling project implemented by researchers at CSIRO (Hoskins et al 2016). The output of this exercise is available as Global 30s (~1km) resolution land use for 2005. Unfortunately, this dataset is available only for the year 2005.

Could anyone suggest a similar product, even a bit coarser (<=10 km resolution), for the future projections?

EDIT: the kind of data I'm looking for has to be based on CMIP5 LU projections (LUH v1) to ensure consistency with the Land Cover used for the climate projections (from the General Circulation of Earth System Models).
In case this does not exist, does anyone know an efficient algorithm I can use to downscale LUH v1?

Thank you.

While this isn't 10km or less, the CMIP6 dataset is released as of last week. It's now at 0.25degree spatial resolution which is an improvement.


What are these underwater structures near 6°N 85°55'W While google earth-researching the sea floor near Malpelo and Cocos Islands (Colombian and Costa Rican Pacific Ocean), I came along these strangely geometrical structures in the sea floor, located around 6°N, 85°55'W. I'm fascinated with the look and the geometric perfection they have, and have waited to ask this question for about 3 years, until today that I realized there's a Stack Exchange site dedicated to earth sciences (I'm not an earth scientist, just a maps enthusiast).

At first I thought they could be due to the path the satellite was traveling at the moment the image was captured, but then I realized there are depth differences in excess of 300m. I find the paralelism of the lines that form the "beams" surprisingly perfect, and the width of the "elements" very consistent (about 7 to 8km, according to google earth's ruler). Near 6°22'N 85°45'W there's a circular "dent" of about 4 $km^2$ that is very perfect regarding ovality.

I found something similar about 670km NE from there, around 11°10'N 82°41'W (160km SW from San Andres Islands, in the Colombian Caribbean). While the structure here is less complex (there's only one "beam" and a concentric circular structure), the width of the "beam" (6km) seems similar to the one near Cocos (the depth differences range between 300 and 500m from the structures to the normal sea floor).

What are these things?

Are they glitches in the images from the satellite, that coincidentially look like beams? If so, why are depth differences so significative?

Are they rocks or some other kind of geological formations? How did they get that shape, and where else cand I find more similar?

As the other answer suggests, these are sonar surveys of the ocean depths. But the answer is a bit more complicated.

The vast majority of the ocean floor has never been mapped. We really only know about the water depth because the water above the sea floor is lighter than if it were rocks. So a deep ocean produces less gravity than a shallow one. And, miraculously, you can fly satellites over the oceans that pick up on how hard Earth pulls on the satellite at any given point and convert that data into an ocean depth.

This is what Google Maps and other mapping services show by default. The problem is that this information is not very accurate: That's because not just the point immediately under the satellite pulls on the satellite, but also points elsewhere. So a very steep undersea mountain will not be distinguishable from a broader but less high one. This is why in general these images of ocean depths are not shown in high resolution -- we just don't know the depth of the ocean on length scales of a few kilometers.

But then along comes the occasional ocean survey. (Think: Research ships, the ships that lay undersea cables, the ships that search for ship wrecks or the occasional plane that fell from the sky.) They tow a sonar array behind a ship, or send a side-scan sonar equipped submersible, to actually map the ocean floor on length scales of a few dozen meters. For map services, this presents a conundrum: They'd like to show the more accurate sonar data where it is available, but they need to overlay it on the low resolution maps that comes from satellites.

This is exactly what you see here: The background is the low-resolution satellite map. Overlaid is the high resolution sonar data. At the edges of the sonar maps, these two maps won't match, and so you will see the sharp edges. You can see the different resolutions if you zoom in and out of the view you showed.

(Given the long straight tracks of these sonar maps, one can guess that in your view, these were created by surveys for laying undersea cables, for example to the  Galapagos Islands.)


Is there a concise industry standard way of displaying wind speed, gust and direction? I'm writing a smart-watch watch-face app with weather details. Since it's on a 1"x1" screen, I'm trying to keep all information as compact as possible. I'm using open weather map for my testing, and have pulled wind speed and gust, but don't know if there's a standard way of formatting a composite value. Currently, I express the following information

Direction: North
Speed: 8 (units per second is definable in user settings)
Gusts: 12 (defined in same units per second)

as

N 8:12

Which is not very descriptive and looks about like when I wake up. I'd like to use a meteorology standard if one exists. I'm pretty much limited to ascii unfortunately. Does such a standard way to present this information exist?

The colon could be problematic as its function is not directly clear in this context. Maybe you could try:

N @ 8 m/s | G: 12 m/s

or a little shorter:

N 8 (12) m/s

The way you created it should not be problematic. However, especially if you make it possible for users to chose the unit, the unit should always be displayed. Here, the standard way in meteorology is to use meters per second [m/s], which is also complying to the SI units (more info here).

The wind direction is often divided into two directional vectors, $u$ and $v$. However this is more science standard than industry standard as the ouput in degrees is more intuitive to interprete. In meteorology and climatology, the direction is only expressed in direction charcters (N, NE, E, ...) if the measurement or model output is not accurate enough to express it in directional degrees or if very exact values are not required, as for example in popular weather forecasts. (Notice that you can make it more exact by dividing the scale into smaller steps: Between N and NE, there is NNE, NEE, and so on).


Which months in Japan probability lowest of natural disaster? I want travel Japan but it gets earth quakes, tsunamis, typhoons. Which months lowest probability of these natural disasters?

There is no season for earthquakes or tsunamis. They can hit at any time of the year, and at any time of the day or night.

Typhoons happen in the warm season, but they will be forecast by the meteorological service, giving you time to move to a safe area.

If you want to go to Japan, just go. It is better to go in the season you want to go than to try and avoid earthquakes and typhoons, as they happen in random places out of anybody's control.


A better way to prevent ice shelf from melting and raising ocean levels? I just read this article by scientist who propose making giant snow machines to basically move the eroding ice shelf further inland. It’s been described as pretty much cost prohibitive (despite saving the coasts from rising water levels??) and would be on the same level of effort as putting a base on the moon.

Here’s the link: https://advances.sciencemag.org/content/5/7/eaaw4132

So instead of doing that, why not drill a large hole straight down into one end of a section of the ice shelf (closest to land but still a thick part of ice) and insert a large tap and then use large fresnel lens to melt a slope in the ice and funnel the melted ice into the hole and out the spout to be diverted further inland which would eventually refreeze later?

You would just have to melt the section of the ice shelf at a graded slope so that gravity does all the work. If you look at how water towers work and then consider the thickness of the ice shelf, you could calculate amount of water pressure and will see that it would suffice to move large quantities of water at a very fast pace.

Just a thot

The problem is that "inland" is uphill from the sea. If you can cause gravity to make water flow uphill, you can solve many more problems than just sea-level rise.


How to predict when the pressure will change For example, on windy.com I see that there is a high pressure area to the west of Washington in the Pacific Ocean. What heuristic techniques could I use to guess if the high pressure area will migrate towards the city of Seattle.

Predictability of weather and climate is currently an active and lively research topic. I will try to giove some (very)  brief information on how it is normally done.

The best idea would be to use a weather (atmospheric) model, which is a numerical model that solves the Navier-Stokes Equations to bring prognostic information of the atmospheric state, for the next couple of days. This allows us to get a reasonably good prediction of high-low pressure zones within a week or so, which I intend is your goal.

Since you mentioned Windy.com, this is already a good source of information on weather prediction, probably one of the best compilation of weather models you can get nowadays. In the bottom right corner of the screan in windy.com (if using a desktop), you will see the acronyms GFS, ICON and ECMWF, for example. These are three models developed by possibly the three best centers in the world (from the USA, Germany and UK, respectively). A similar user-friendly interface, focusing on GFS is available at Earth Nullschool. They all bring a timer, so that you can choose the time of your prediction. Since you are asking specifically about a pressure system, I will assume you know how identify it in the images provided by these interfaces.

The predictability of weather for the next few days is good, and the predictability of "seasonal climate" is not bad either. For some time scale in between (subseasonal), there has long been a "grey zone of predictability". This is where cutting-edge research in Climate Science currently takes place. Sources of predictability, generally comes from a thorough understading of climatic phenomena (e.g. ENSO, NAO) and their relationship with the predicted variable. The NAO is known to modulate weather in North America and Europe in the day-to-day time scale, for example. ENSO is the dominant factor for tropical latitudes, with a lower-frequency variability.

This type of research is normally done using numerical weather and climate models, not so different from the ones in windy.com, often combined with statistics.

To reed further in the seasonal and decadal time scales.


Is there a difference between Density and Specific Gravity? My textbook says that the specific gravity is "the ratio of the mass of a mineral compared with the mass of an equal volume of water."

Is this any different to density? If so, how? If not, why does it have its own name in geology?

It is different to density but they are closely related. This is easily seen by considering the dimensions of the two quantities (side note: always consider the dimensions of quantities - it is invariably useful).

If you read your definition carefully you will realise that specific gravity is defined as the ratio of the density of the material to that of water. $$\mathrm{SG = \frac{\rho_{sample}}{\rho_{water}}}$$

Historically I suspect that specific gravity was used rather than density because it is easy to measure by measuring the mass of the displaced water when you place the sample into a jar of water, and the mass of the sample itself. You don't actually need to know the density of water in order to calculate the specific gravity.


viable geothermal energy supply from exhausted fracked gas wells? The UK legislator with primary responsibility for energy has claimed that exhausted fracked natural-gas wells will be suitable for re-use as a geothermal energy supply (not necessarily geothermal for electricity production, but rather for heat distribution, so let's say 80° - 250°C).

Is there much of a co-location of the geo-thermal resource in the UK, with the more easily obtained frackable natural gas; and would an exhausted fracked well be structurally suitable for this?

Viability of an oil or gas well for geothermal energy production is dependent upon several factors:
 - Geothermal heat profile with depth near the well
 - Depth of the exhausted well
 - Volume of fluid acting as a heat exchange around and near the well.

I think it might be possible to use exhausted natural-gas wells will be suitable for re-use as a geothermal energy supply. Likelihood of success would require site investigation and the engineering pilot study.  This idea would be ideal for university engineering / geology research.


How can I test my house water supply for hydrocarbon presence? I live in a city where the water supply quality seem pretty good on daily/average basis. However, it is also well known that there is a huge problem with deteriorating water pipes. My problem is that every now and then, there is a very light and brief smell of hydrocarbons coming from the drinkable tap water. I say hydrocarbons, because it smells a bit like what you smell at a petrol/gas station. But in reality, don't know what it is.

How can I test my water myself for hydrocarbon presence?
Where can I obtain such a test without having to spend a fortune on expensive equipment or buying "testing services"?

EDIT: 2018-07-25

I found a company that offers various test kits two of which may be used to find petroleum-like contaminants. Unfortunately these tests are rather expensive.

Chances are you do not have presences of fuel in your water. This sounds like you could have a few different things happening.
First off, iron reducing bacteria can lead to significant corrosion. These are bacteria that feed on iron both in the water and also in plumbing systems. They also can put off a smell.
The second one is manganese. If you notice this smell after rain, etc. then this is a possibility. Manganese can make the water blackish and smell like fuel oil. While mostly harmless, it can cause issues with staining, etc.
If you have a private well and live in a hard water area, both of these could be occurring simultaneously. Correlation is not always causation. What the smell is vs. what is causing the corrosion could be separate issues.
Lastly, if the pH is off in the water, too acidic or too base then this can also eat away at your pipes. Typically though, many water quality smell and plumbing issues come from bacterial issues. Check this first and then move on if negative.


Can someone provide a map of Nazca lines with this image in it? I found this image of a bird with another image below its right wing on google earth in nazca peru. Is there any maps or infomation available that can help me identify this one?

Kind regards
Jeff B.

go2peru  has a nice set of maps of the Nazca area.


How do meteorologists grade their past forecasts? In every professional field, practitioners may come home at the end of the day and say "Yeah! I knocked it out of the park!", or alternatively "Oh, man. Gotta do better tomorrow." What about meteorologists?

When a meteorologist makes a weather forecast, she will strive to "get it right", so that when the date in question arrives her prediction will have matched the actual temperature, dew point, wind velocity and direction, precipitation, etc. But, when that date arrives, and the actual conditions have been measured and compared to the prediction, how is the prediction graded?

Precipitation seems to be the most problematic aspect, as it's quite nonlinear and predicted statistically. What does it mean to have "gotten it right" by predicting a 30% chance of precipitation? Yes, it rained 30% of the time? Yes, it rained in 30% of the forecast area? Yes, 30% of the public will answer "Yes" if asked whether it rained?

There's complexity in the other metrics as well. For instance, how are errors in the different values compared? Would it be better to get the temperature spot on but the wind velocity 5MPH high, or the wind exactly right but the temperature 5°F high? What about timing: what if that front came through two hours after it was predicted?

Edit: part of the difficulty is getting clarity about the consumer of the weather information. Fred the Farmer wants to know how much rain he can expect in next day or so, but the exact timing probably isn't important. Pete the Party Planner wants to herd his guests into the bar before the front comes through, but if it's going to rain he probably doesn't care whether it drops a quarter inch or a half. And Francine the Fisherman doesn't really care about the precipitation at all (within limits); her world centers around wind and waves.

I may want to post a second question that is explicitly from the consumer viewpoint: given weather data and meteorologists' historical forecasts, how would I choose a meteorologist?

Disclaimer: I am not a meteorologist.

To answer this question, you need to understand how a forecast is obtained. Basically, meteorologists run computer simulations that predict how weather systems might evolve from current measurements. In fact, data assimilation techniques (http://en.wikipedia.org/wiki/Data_assimilation) are commonly used, so that the predictions given by the model depend not only on current observations, but also upon the history of the weather system. As new data comes in, the evolving model is adjusted towards those values - but not forced to match exactly, as that would destroy the historical information.

Any one model is therefore not expected to be entirely accurate. However, if we run many models simultaneously, and include random variations to reflect the chaotic nature of the weather system (and measurement errors), we obtain something called an "ensemble forecast". This is where the 30% chance of rain comes from: 30% of the simulations predict rain in your area, while the others think it will remain dry. Average/minimum/maximum temperatures etc can also easily be extracted from the ensemble.

So, the accuracy of a forecast can be considered in different ways. It is certainly possible to compare the predictions of one ensemble member to observations: this is an integral part of the data assimilation process. However, it is not necessarily a problem if a member performs poorly on one particular occasion. Different types of measurements may be weighted differently during the comparison (so matching rainfall might be deemed 'more important' than matching temperature; this may vary depending on the type of forecast/its intended use). More generally, you have to look at the long-term statistics of the errors in the forecast. So, if you look at several months of data, did it rain on around a third of the days when you predicted a 30% chance of rain? On average, are your temperature predictions reasonably accurate? Making this assessment on a day-by-day basis is unlikely to be in keeping with the statistical basis of modern weather forecasting.


Anyone sucessfully installed pywafo for Python 3 under windows OS? I've tried:
pip install wafo
pip install wafo==0.3.1

The instructions of readme provide a 2 step installation process but it fails on the first one.

I am using windows 10 and python 3.6.1.

Right now, rather than assistance to make it work I would just like to know if I'm on a fools errand or if its actually possible to install wafo for python under configurations like I have.

Appreciate any reply.

this is probably a little late in the day to answer. I have a wafo "superficially working" on windows 10 with python 3.7.1: however, so far I have only accessed the wave spectrum models. The recipe I used was

clone the repo
pip install 2to3
navigate to the cloned folder
2to3 . -w
copy folder to src/wafo folder to site-packages/wafo
Open cmd.exe or something better e.g. ConEmu
Assuming your python.exe is in your PATH. type ... python -c "import wafo"
Then address each problem in turn...

There aren't many problems to address if all you need are the wave spectrum models. It took me an hour to hack the source code to access these. If you need to access the whole suite of functionality, continue the approach. You may need to recompile the c-libraries if they are needed.

Sorry I can't provide a comprehensive list of the changes I made to get wafo to import. Here are the ones I remember

It will complain about "import scipy.lib.six". Change to "import six" (install it)
It will complain about scipy's piecewisepolynomial. Change to PPoly
It will complain some version checks ... set to True as your module versions are no-doubt much newer than the versions 5 years ago.


How fast does the Earth's inner-core spin? How fast does the Earth's inner-core rotate compared to the Earth's daily rotation?

The inner core is always described as a spinning/rotating solid core while the Earth has a single revolution per day. I've always imagined it as a fast spinning top, but realised I don't actually know if it is a faster spin or slower spin when compared to the Earth's rotation.

And even if I knew the speed (which I don't), a number doesn't mean anything unless compared to something relatable.

So how much faster/slower is the core rotation compared to the 24 hour day rotation?

Eg the inner core rototes 25 or 2.5times per 1 day. Or the inner core rotates 0.5 times per 1 day.

Roughly once per day, but a tiny bit faster. As the website for Columbia University's Lamont-Doherty Earth Observatory says:

  The inner core rotates in the same direction as the Earth and slightly faster, completing its once-a-day rotation about two-thirds of a second faster than the entire Earth. Over the past 100 years that extra speed has gained the core a quarter-turn on the planet as a whole...

Off the top of my head, I would have doubted that the core had a significantly different rotation rate than the mantle and lithosphere, because it would create different mixing layers in the liquid outer core, resulting in tangles in the Earth's magnetic field, similar to what happens in the Sun.


How to find SMAP Satellite acquisiton plan? I need to know to which time the SMAP Satellite passes over a certain location in the future.

I believe this is called acquisition plan, but I'm not sure. Here for example the sentinel 1 acquisition plan.

I found this web page where you can track the actual position of SMAP and get a 10day prediction but I need a more official source.

As @gerrit pointed out, the Pytroll project has a couple of package which could be useful.
To answer your question and get the next overpasses for the next twelve hours above a given location, you can use Pyorbital (https://github.com/pytroll/pyorbital):

from pyorbital.orbital import Orbital
from datetime import datetime
orb = Orbital("SMAP")
orb.get_next_passes(datetime.now(), length=12, lon=16, lat=55, alt=0.05)

with length in hours, lon and lat in degrees, alt in km. And this will display (at the time of writing this):

[(datetime.datetime(2020, 2, 24, 13, 14, 54, 147587),
  datetime.datetime(2020, 2, 24, 13, 23, 23, 955297),
  datetime.datetime(2020, 2, 24, 13, 19, 8, 924860)),
 (datetime.datetime(2020, 2, 24, 14, 48, 41, 249324),
  datetime.datetime(2020, 2, 24, 15, 1, 24, 171709),
  datetime.datetime(2020, 2, 24, 14, 55, 1, 725148)),
 (datetime.datetime(2020, 2, 24, 16, 25, 14, 798347),
  datetime.datetime(2020, 2, 24, 16, 39, 0, 109628),
  datetime.datetime(2020, 2, 24, 16, 32, 5, 434271)),
 (datetime.datetime(2020, 2, 24, 18, 5, 14, 617775),
  datetime.datetime(2020, 2, 24, 18, 15, 43, 280401),
  datetime.datetime(2020, 2, 24, 18, 10, 27, 671621))]

Each tuple is (rise, fall, highest point).

Now we also have the pytroll-schedule package, in case you need to make a full acquisition plan, that will allow you for example to put priorities on satellites:
https://github.com/pytroll/pytroll-schedule


What current evidence is there for a Glacial Hudson River Valley deluge? Some have studied the Lake Missoula glacial dam breaking West and having created the Coulees of Eastern Washington.  Who's studied the glacial dam breaking South and having cleared the Hudson River valley, forming the Verrazano Narrows, NY Harbor, Staten and Long Island, and washing through to the Atlantic Continental Shelf?

" Who's studied the glacial dam breaking South and having cleared the Hudson River valley, forming the Verrazano Narrows, NY Harbor, Staten and Long Island, and washing through to the Atlantic Continental Shelf?"

There's a USGS group at Woods Hole that's done a bit of work on this back in 2004:

A catastrophic meltwater flood event and the formation of the
Hudson Shelf Valley   -From the paper:

The ancestral Hudson River is generally thought to
have had a long history that began in the Late Cretaceous.
Uplift and tilting of the margin, resulting in
landward erosion and seaward growth, continued into
the Tertiary.

The Hudson River was repeatedly downcut into Cretaceous
coastal-plain strata during periods of Pleistocene marine
regression.
Scouring of the lower Hudson River during the last
glaciation formed a fiord in the region north of New York
City.
More recent fluvial downcutting was amplified by
drainage of late Wisconsinan glacial lakes, culminating in the failure of the terminal
moraine dam at the Narrows, which is a break in the
Harbor Hill moraine between Staten Island and
Long Island, New York. Borehole data across the
Narrows suggest that more than 100 m of Pleistocene
and Cretaceous sedimentary material was eroded as a
result of this breaching event. Uchupi et al. (2001) proposed that deposition
of sediment lobes on the continental shelf and erosion of the HSV were a consequence of
this catastrophic drainage.

You might scour the references at the back of the paper and do some googling to find any more recent follow-up work they may have done. You could also try this guy at Woods Hole: Jeffrey P. Donnelly. He's first author on a paper titled:

Catastrophic meltwater discharge down the Hudson Valley: A potential trigger for the Intra-Allerød cold period

The paper is short on the drama of breached glacial dams, but long on how the sudden discharge of freshwater into an ocean alters circulation to cause a brief period of climate change. Fascinating stuff!


What level of heat creates a dust devil? My understanding is that a dust devil is created when heated air rises rapidly displacing the cooler air above up. My question is, how relatively hot does the patch of air on the ground have to get in order to create a dust devil, and how is the heat related to the height and size? And secondarily, do dust devils tend to occur more frequently within a certain range ambient temperature?

When a parcel of dry air with a given initial temperature rises, it cools at a specific rate - the dry adiabatic lapse rate. If the surrounding environment cools at a slower rate with height than the parcel, the parcel will eventually be colder than the environment and sink. On the other hand, if the environment cools faster than the parcel does, the parcel remains warmer than the environment and rises freely.

So for a parcel of dry air to continue to rise, the environmental lapse rate needs to be greater than the dry adiabatic lapse rate. Surface heating does a really efficient job of increasing low-level environmental lapse rates, which is why dust devils are more common when there's more sun.

I'm not a scientist, so I can't tell you an exact number, but the dry adiabatic lapse rate is 9.8 degrees Celsius per kilometer, or 3.3 degrees Fahrenheit per 1,000 ft. So if the environment cools at over 1 degree C per 100 meters, it will likely be conducive to dust devils.


How do perennial rivers in high alpine areas maintain year round flows? We have several perennial rivers in my country that originate out of high altitude alpine glacier melt. I can understand snow or glacier melting in the summer to increase the flows but it is observed that flows do not come to a  complete halt during peak winter as well even though temperatures maybe below freezing point. Upon investigation it was revealed that a process called calving(presumably pressure differences)  is responsible for glacier breakdown but wikipedia claims that the mathematics of this process is still in development.
Is it possible to get an expert answer on this phenomenon ?

Not claiming to be an expert, but I think the process you're referring to is called pressure melt. This effect occurs when the pressure at the bottom of the glacier is high enough to either shift the melting point slightly (melting point decreases by 0.7$\,^{\circ}$C per km of ice according to this link, which provides some more background information on processes and conditions inside glaciers), which combined with frictional energy from the constant movement of the glacier, and, in some regions, geothermal energy causes a constant supply of liquid water. Since these discharges are usually concentrated under the ice (also the principle behind the formation of eskers), leading to large discharges at a few emergence points with enough energy to prevent them from freezing over.


What amount of permafrost carbon release could be expected with the IPCC worse-prediction of a 4.8C temperature rise? As answered in my earlier question How much methane clathrates are buried in continental deposits?, there is alot of methane trapped in the form of clathrates in continental deposits.  Additionally, according to the National Snow and Ice Data Centre webpage Methane and Frozen Ground states that the

  estimate that there are about 1,400 gigatons of carbon frozen in permafrost.

According to the webpage, this is more than exists in the atmosphere, but it is unlikely to be released at once (due to depth, local conditions etc).

The recent IPCC 5th Assessment Report stated that

  Without additional efforts to reduce GHG emissions beyond those in place today, global emissions growth is
  expected to persist, driven by growth in global population and economic activities. Global mean surface
  temperature increases in 2100 in baseline scenarios – those without additional mitigation – range from 3.7 to
  4.8°C above the average for 1850-1900 for a median climate response.

(GHG = Greenhouse gases)

They also state, in regards to permafrost,

  It is virtually certain that near-surface permafrost extent at high northern latitudes will be reduced as global
  mean surface temperature increases, with the area of permafrost near the surface (upper 3.5 m) projected to
  decrease by 37% (RCP2.6) to 81% (RCP8.5)for the multi-model average (medium confidence).

What amount of permafrost carbon release could be expected with the IPCC worse-prediction of a 4.8C temperature rise?

(If any published studies are available, that would be good too).

Note: this carbon source is not explicitly covered in the question and answer for How is carbon distributed among the atmosphere, the oceans, the biomass and the unburnt fossil fuels?

Schneider von Deimling et al. in Estimating the near-surface permafrost-carbon feedback on global warming Biogeosciences, 9, 649–665, 2012 evaluated carbon dioxide and methane release under four senarios, the worst being RPC8.5.

Under RPC8.5, they calculated release of carbon from permafrost through 2100 of 63 gigatons (Gt) as CO2 and 0.5Gt as methane.

Through 2200 (cumulatively): 302Gt as CO2 and 5Gt as methane.

Through 2300: 380Gt as CO2 and 12Gt as methane.

Other estimates and nice figures are in the UN Environmental Program report Policy Implications of Warming Permafrost


How high must one be for the curvature of the earth to be visible to the eye? I would like to ask that at what distance from the Earth's surface the curvature of the Earth is visible. What layer of the atmosphere is this?

I've noticed that at the height of 9-12 Km (the view from from aeroplanes) it is not visible.

Depends on your eye. You can realise the curvature of the Earth by just going to the beach. Last summer I was on a scientific cruise in the Mediterranean. I took two pictures of a distant boat, within an interval of a few seconds: one from the lowest deck of the ship (left image), the other one from our highest observation platform (about 16 m higher; picture on the right):

A distant boat seen from 6 m (left) and from 22 m (right) above the sea surface. This boat was about 30 km apart. My pictures, taken with a 30x optical zoom camera.

The part of the boat that is missing in the left image is hidden by the quasi-spherical shape of the Earth. In fact, if you would know the size of the boat and its distance, we could infer the radius of the Earth. But since we already know this, let's do it the other way around and deduce the distance to which we can see the full boat:

The distance $d$ from an observer $O$ at an elevation $h$ to the visible horizon follows the equation (adopting a spherical Earth):

  $$
d=R\times\arctan\left(\frac{\sqrt{2\times{R}\times{h}}}{R}\right)
$$

where $d$ and $h$ are in meters and $R=6370*10^3m$ is the radius of the Earth. The plot is like this:

Distance of visibility d (vertical axis, in km), as a function of the elevation h of the observer above the sea level (horizontal axis, in m).

From just 3 m above the surface, you can see the horizon 6.2 km apart. If you are 30 m high, then you can see up to 20 km far away. This is one of the reasons why the ancient cultures, at least since the sixth century BC, knew that the Earth was curved, not flat. They just needed good eyes. You can read first-hand Pliny (1st century) on the unquestionable spherical shape of our planet in his Historia Naturalis.

Cartoon defining the variables used above. d is the distance of visibility, h is the elevation of the observer O above the sea level.

But addressing more precisely the question. Realising that the horizon is lower than normal (lower than the perpendicular to gravity) means realising the angle ($gamma$) that the horizon lowers below the flat horizon (angle between $OH$ and the tangent to the circle at O, see cartoon below; this is equivalent to gamma in that cartoon).  This angle depends on the altitude $h$ of the observer, following the equation:

  $$
\gamma=\frac{180}{\pi}\times\arctan\left(\frac{\sqrt{2\times{R}\times{h}}}{R}\right)
$$

where gamma is in degrees, see the cartoon below.

This results in this dependence between gamma (vertical axis) and h (horizontal axis):

Angle of the horizon below the flat-Earth horizon (gamma, in degrees, on the vertical axis of this plot) as a function of the observer's elevation h above the surface (meters). Note that the apparent angular size of the Sun or the Moon is around 0.5 degrees..

So, at an altitude of only 290 m above the sea level you can already see 60 km far and the horizon will be lower than normal by the same angular size of the sun (half a degree). While normally we are no capable of feeling this small lowering of the horizon, there is a cheap telescopic device called levelmeter that allows you to point in the direction perpendicular to gravity, revealing how lowered is the horizon when you are only a few meters high.

When you are on a plane ca. 10,000 m above the sea level, you see the horizon 3.2 degrees below the astronomical horizon (O-H), this is, around 6 times the angular size of the Sun or the Moon. And you can see (under ideal meteorological conditions) to a distance of 357 km. Felix Baumgartner roughly doubled this number but the pictures circulated in the news were taken with very wide angle, so the ostensible curvature of the Earth they suggest is mostly an artifact of the camera, not what Felix actually saw.

This ostensible curvature of the Earth is mostly an artifact of the camera's wide-angle objective, not what Felix Baumgartner actually saw.


Debunking weather conspiracy with statistics - why does temperature rise then fall for last weekend in June in recent years I have a conspiracy-prone friend who believes that people are controlling the weather to ensure good weather for a large, annual festival (last weekend in June in San Francisco). As a scientist, (not earth science), I was interested in testing this hypothesis. So..I built 2 linear models--one representing the days leading up to the festival, one representing the days following the festival-- where the I regressed max daily temperature onto the number of days away from the festival. Lo and behold, indeed the temperature did appear to rise, peak on the weekend of the festival, and then drop afterwards! Next I figured, it must just be a natural trend, irrespective of local festivities (and weather-controlling overlords). So next, I included data from the years before the festival began (1972), made two groups (pre-festival and post-festival) and included a days_away_from_festival*group interaction term. To my great surprise, the interaction was significant! Testing only the group dated before the festival began, did not yield significant results.

And so! My question is... can any of you experts explain this by means other than a statistical coincidence/wealthy weather gods? Why might the temperature in San Francisco tend to rise in the week leading up to the last weekend in June, and then fall afterwards--but for this effect not to be present in the years before 1970'sish?

EDIT: Here are my two models.

The first model represents the days leading up to the festival and days are indicated by the countdown variable, (e.g. Friday = -1, Saturday = 0) There are 5 days prior included in the model. The group variable refers to the fact that I split the years into two groups, old:(1942-1971) and new:(1972-2017). TMAX is the maximum temperature of the day.

The second model is the same except it represents the days following the festival.

As you can see, after 1972 the temperature seems to rise, peak during the festival in the last weekend in June, and then fall immediately after. However, this effect was not present prior to 1972.

EDIT2: The data came from https://www.ncei.noaa.gov and the station is San Francisco Downtown

You are asking the wrong question. The real question is why some podunk single city festival and not other larger more costly events, like space launches, national holidays, military campaigns, hurricanes, or a million other festivals. The conspiracy theorists likely picked that festival through data dredging, which means you are not going to disprove it by looking at the same data. If you compare enough festivals you will find some in which the weather does weird things, it is the law of large numbers in action.

A festival that started in the 1970's is perfect for data dredging, there is a change in the underlying forces of weather in the 1970's. The undeniable warming trend in global climate starts around the 1970's so if you divide your data sets before and after any point around that time the data will always show a significant difference, unless you correct for that shift. Without correcting for it all you are detecting is climate change, a known factor,n anthropomorphic factor at that. So really humans are altering the weather, just not in the way your friend thinks.


Will tropical cyclones form and be sustained in areas they previously were not due to global climate change? With global climate change, is it possible that tropical cyclones (as seen in the Atlantic basin for example) are going to form and be sustained in regions where they previously did not, for example near Europe?

The short answer is no.

Tropical cyclones (TC) develop and persist in conditions favorable to them:

1) Low Coriolis parameter $f = 2\Omega \sin{\theta}$, where $\Omega$ is the angular velocity of Earth and $\theta$ is latitude. If $f$ is small, the centripetal force balances the pressure gradient force in the gradient wind balance, and the radius of curvature becomes small. While this is one of the reasons why TCs form in the tropics, that still does not prevent the storm to move North and re-curve into Western Europe or Northern California. This limits the latitude extent of the region of TC genesis to approximately 5-30 N (or S). This factor is most certain and not subject to climate change.

2) TCs get the energy from sensible and latent heat fluxes at the surface. Thus, they form over the ocean and it needs to be warm. Historically popular threshold of sea surface temperature (SST) necessary for a TC to develop was 26$^{\circ}$C. Nowadays, we know that this is not enough - TCs need a significant thickness of the upper ocean to be warm in order to get enough heat to be sustainable. Another reason why the ocean is more favorable for TCs than land is surface friction - the air flow over the ocean surface is typically much more aerodynamically smooth compared to over land. Low wind stress and high heat fluxes are key. Though the wind stress is not going to change, heat fluxes may increase if the ocean heat content in the tropics increases (for example, by weakening of the Meridional Overturning Circulation).

3) TCs also need favorable atmospheric conditions in their environment - namely, high humidity (water vapor content) in the environmental air, and low wind shear (difference between wind in the upper and lower troposphere) facilitate TC genesis and longer life. These factors are, in my opinion, least understood of the three, especially in terms of their contribution to the vortex dynamics and vortex-mean flow interaction. This aspect is more likely to be subject to climate change compared to the others.

All this being said, we may see a change in the occurrence frequency of TCs in the future, and/or a change in the distribution of the extreme weather events. However, the mechanisms in the climate that would lead to this change are still not well understood. It is unlikely though that the TCs will start forming in new regions around the world.


Is the effect of Earths position relative to sun large or small compared to CO2 level in climate change? A recent answer by Camilo Rada for "What place on Earth is closest to the Sun?" inspires this question. He makes clear that significant changes in the wander of the earth through its orbit results in striking effects on how close the closest distance is between these two bodies.  In the same thread others point out the height of solar flares relative the the baseline surface of the boiling hydrogen ball are likely even larger effects.  It is intuitive to me that the distance to the main producer of heat on the Earth SHOULD be a much larger effect than concentration of a gas in our atmosphere.  Is this a reasonable intuition?

So my questions has four parts:

1) Generally, do the big dog scientists modeling for climate change in the next 100 years take these apparently very large effects into account in their models and how big of an effect is this compared to CO2 ppm levels?  It would be nice to have an answer in some sort of statistical level of confidence.

2) Another way to consider this is how big of an effect is this variable compared to the expected CAUSES of CO2 ppm levels: combustion on earth of various kinds, respiration and farting of living species, chemical processes, etc

3) Can the sun's energy level, solar flare activity be modeled and used to predict, in the absence of CO2 ppm level changes, the temperature on earth in the future 5 years.?

4) As Mr. Rada points out in the referenced thread is this distance changed on such a limited timeline as to make it NOT as relevant or a lot smaller effect than it first seems?

The changes Camilo Rada discusses repeat annually so they average out over longer timescales and have no effect on climate. The flares reach less than $1\%$ of the distance to earth and they are a recurring effect so they also average out.

Greenhouse gases have a cumulative effect.

Solar activity is included in the IPCC.


How long it takes to cool a planet? Suppose a planet like Earth or Venus is totally isolated from sunlight. How quick would it cool down?

On Earth it seems to me that the air temperature drops significantly even during a night. Does it mean that if we screen Venus of Sun's radiation with some untransparent cloud, it would cool down rather quickly, and not for millions of years as some may expect?

Not a full answer as that is hard to give.  But:

This is a diagram by Kevin Trenberth picturing energy flows in the Earth climate system:

(Source: Skeptical Science)

In the hypothetical extreme case of blocking all incoming solar radiation, the Earth would — initially — have a net heat loss of roughly 340 $W m^{-2}$.

93% of net radiation change on Earth enters the oceans.  In the past 20 years, this has led to an increase in ocean heat content (OHC) of roughly $10^{23}$ J.  With a 340 W m^{-2} heat loss, undoing that would take $10^{23} J / ((340 W/m^2) * .7 * 510 * 10^6 km^2$ which is roughly 10 days.  Although this is a severe oversimplification, it does give us a first order of magnitude.

It might be possible to run a climate model and switch off the Sun, just for fun.  You don't need a heavy climate model to do so.  PlaSim is good enough to get a handle on it.

My guesstimate is that it would take a couple of months before mid-latitude oceans start to freeze.

(Source: EPA)


How will global warming affect climate systems like the ENSO or the MJO? How will global warming influence climate systems such as the Madden–Julian Oscillation (MJO) or the El Niño Southern Oscillation (ENSO)?

Still undetermined, though a number of papers on the subject suggest global warming will increase the variance in both of the climate systems you mention. They suggest more research and more refined models are needed to narrow down the uncertainties.

Some definitions:

  The Madden-Julian Oscillation (MJO) is the major fluctuation in
  tropical weather on weekly to monthly timescales. The MJO can be
  characterised as an eastward moving 'pulse' of cloud and rainfall near
  the equator that typically recurs every 30 to 60 days. (Australian Bureau of Meteorology)

  The El Niño/ Southern Oscillation (ENSO) cycle refers to the coherent
  and sometimes very strong year-to-year variations in sea- surface
  temperatures, convective rainfall, surface air pressure, and
  atmospheric circulation that occur across the equatorial Pacific
  Ocean. El Niño and La Niña represent opposite extremes in the ENSO cycle. (National Weather Service Climate Prediction Center)

El Niño is the "warm phase" of sea-surface temperatures in the east-central equatorial Pacific with a variety of effects on regional and global weather. La Niña is the "cold phase" of the oscillation.

One of the predictive challenges is that climate change is not monotonic. It's generally held that will be a "warmer-get-wetter" impact -- warmer oceans produce more evaporation and therefore more precipitation. But ocean states are also affected by highly complex relationships involving currents and convection.

Here are extracts from the abstracts of a couple of recent papers on the subject(s) (actual papers are paywalled):

In Intermodel Uncertainty in ENSO Amplitude Change Tied to Pacific Ocean Warming Pattern, Zheng, et.al. compare actual sea-surface temperature measurements to the outputs of various models and write:

  To the extent that correcting model biases favors an El Niño–like mean
  warming pattern, this study suggests an increase in ENSO-related SST
  variance likely under global warming.

In The MJO and global warming: a study in CCSM4, Subramanian, et.al, write:

  The RCP8.5 run exhibits increased variance in intraseasonal
  precipitation, larger-amplitude MJO events, stronger MJO rainfall in
  the central and eastern tropical Pacific, and a greater frequency of
  MJO occurrence for phases corresponding to enhanced rainfall in the
  Indian Ocean sector. These features are consistent with the concept of
  an increased magnitude for the hydrological cycle under greenhouse
  warming conditions.

In MJO Intensification with Warming in the Superparameterized CESM, Arnold, et.al. said their modeling runs showed "Intraseasonal precipitation increases at a rate of roughly
10% per 1 K of warming, and MJO events become 20%–30% more frequent," but conclude:

  This work adds to existing evidence that MJO activity may increase in
  response to global warming. Evidence for an MJO dependence on SST has
  been identified in observations (Hendon et al. 1999; Slingo et al.
  1999; Jones and Carvalho 2006; Oliver and Thompson 2012), and in some
  numerical models (Lee 1999; Caballero and Huber 2010; Arnold et al.
  2013; Schubert et al. 2013). However, other models have shown negative
  or neutral trends with SST (Takahashi et al. 2011) or a strong
  dependence on the spatial pattern of warming (Maloney and Xie 2013),
  so any conclusions regarding future trends should be viewed as
  tentative.


High-resolution georeferenced population data Can anyone recommend a good source for high-resolution georeferenced population data? I know that Natural Earth Data's Cultural Vectors e.g. contain the population per country. However, I am looking for georeferenced global population data with a higher resolution than on a country level. Obviously, Wikipedia and other sources feature data for some country's states or cities but is there a database (ideally) georeferenced which features such data on a global level?

For "historical" population data, you can refer to the Gridded Population of the World (GPW), version 4. This dataset makes available estimates of population at ~1 km resolution (30 arc second) for the years 2000, 2005, 2010, 2015, 2020.

The GPWv4 was also used by the European Commission's Joint Research Centre for the Global Human Settlement project. This dataset makes available residential population estimates for target years 1975, 1990, 2000 and 2015 at 250m and 1km spatial resolution.

If you also need future projections, you can refer to the Shared Socioeconomic Pathways (SSP) scenarios downscaled by Murakami and Yamagata (2019), available here, or by Jones and O'Neill (2016), made available through the ISIMIP project portal.


How effective is seeding rainclouds? What are the indications for initiating seeding? I've heard that dry ice, iodides have been used as seeding agents to induce rainfall. Is this technique really being used widely? What are the prerequisites for initiating seeding? Is it as bounteous as natural rainfall is?

Cloud seeding has been attempted for well over a century, with mixed success. There is no doubt at all that, locally, rain can be increased by seeding the cloud base with such nucleating agents as dry ice or silver iodide smoke. There is a great deal of doubt as to whether there is any overall gain in rainfall - or is it just an expensive way of 'robbing Peter to pay Paul', of increasing rain in one location at the expense of rainfall further downwind. Is there any nett gain in regional rainfall? Probably not. Of course, there are many cases where locally increased rainfall may be worth the effort.

Not all cases of cloud seeding work. There are several requirements. First, the process involves vigorous convection within the cloud towers in order to loft the nucleating agent into a sufficiently super-cooled part of the cloud. If the cloud is too warm it won't work - which rules out many tropical applications. Second, the 'seed' has to be injected into the cloud base at about -10 to -20 deg C, which allows 'graupel' to form, i.e. a kind of granular ice that flash freezes onto snow or ice crystals direct from super-cooled water vapour. Third, the timing has to be right, just as the cumulus towers are beginning to form, usually in the early afternoon. Fourthy, the economics are very moot. Wikipedia ('Cloud Seeding') claims that the subject is no longer 'fringe science', which is true in that the physics have been studied seriously, but mostly untrue in the sense that it is now considered economically attractive. The great majority of studies have shown that cloud seeding is unreliable, expensive, and of dubious value, with other ways of delivering water (such as desalination) being a better bet.


How will sea level rise be distributed across the globe? Sea level rise from melting glaciers will not be uniformly distributed across the globe.  However, it isn't clear to me what places will have the most and least extreme changes in sea level rise.  I had previously thought that, in general, tropical latitudes would have the least sea level rise, and the polar regions would have the most sea level rise.  However, when I view this map of tidal variation, and also consider the change in mass on the land (when the glacier melts), it appears that sea-level rise will be complex.  I've seen this image of recent sea level change, but I don't think a change of several meters would continue to follow this trend.

How will sea level rise be distributed across the globe?

There are many factors involved, so this is worth yet another answer. At the end of his/her answer aretxabaleta states:

  In general, the areas near the poles have a negative trend (sea level is dropping, not rising) because of the Glacial Isostatic Adjustment (GIA) as the crust is still rebounding from the previous glaciation. In mid-latitudes, on the other hand the sea level rise rates are maximum

In those locations however, there is a stronger effect:

The ice masses themselves exert a large gravitational pull on the surrounding water, resulting in a lowering of the sea level around those masses (Greenland, Antarctica) when the ice melts.
This may seem counter-intuitive, and is best explained by looking at what happens when the ice masses grow:

The gravitation of the growing mass pulls water towards it. The resulting sea level rise on the edges of the ice mass is therefore larger than the eustatic (global, uniform, across the world) sea level decrease that occurs because of the water moving into the ice. The effect is that near the ice mass, sea level actually rises, and far away it falls faster than 'expected'.

When the ice melts the reverse happens: sea level close to the ice mass will drop, sea level far away will rise more than 'expected'.

To give this some actual numbers:
The eustatic sea level rise corresponding to the melting of the Greenland and West Antarctic ice caps is both approx. 6 meters.
Here in Europe (I live in the Netherlands) however, the Greenland melt would 'only' result in approx. 3 meters rise, because that is relatively close, but the West Antarctic melt would result in something like 8-9 meters extra water.

This picture shows the relative effect calculated for water running of West Antarctica. You should read the numbers as a multiplication factor to apply to amount of sea level rise in the case of a uniform distribution.

  Sea level change associated with a uniform thinning of the West Antarctic Ice Sheet (WAIS). Their result, reproduced in Fig. 1(a), was normalized by the eustatic sea level change (i.e. the change computed assuming that the meltwater entered the present-day ocean uniformly). [...] The map shows a peak sea level rise greater than 25 per cent above the eustatic value in the north Pacific and more than 20 per cent above the eustatic in the north Atlantic and Indian Oceans. In addition, the sea level fall is greater than five times the eustatic amplitude in the ocean adjacent to the West Antarctic.

On the robustness of predictions of sea level fingerprints
J. X. Mitrovica, N. Gomez, E. Morrow, C. Hay, K. Latychev, M. E. Tamisiea
14 October 2011
DOI: 10.1111/j.1365-246X.2011.05090.x


Are there measurement techniques that can help determine the exact geometry of a volcanic vent? In a previous question What happens to the higher frequency content of the tremors associated with a volcanic eruption?, I asked about the high(er) frequency content of a volcanic eruption.

In the same vein, I'm interested to know more about the influence of the geometry of the magma column on this particular frequency content and the methodologies that researchers use to take measurements of circular vents.  Assuming a uniform cylinder all the way to the magma chamber would aid in the mechanical modeling, but I'm sure this betrays quite a bit of the changes in diameter that take place along the way.

Are precise measurements of the vents/magma conduits of volcanoes currently possible, or is this too big of a risk to personnel and equipment?  Which particular techniques (e.g., radar/sonar) would work without having to actually enter the chamber?

Interferometric synthetic aperture radar (or InSAR) is a remote sensing (airplane or, more commonly, satellite) radar techinque used to measure surface deformation. Repeated measurements of radar amplitudes over a common area are used to estimate changes to surface topography. InSAR measurements of surface changes have been used with numerical models of dyke propagation to model magma chambers in the East African Rift System.

Other geophysical methods that can be used to image/model active magma chambers include seismic interferometry, magnetic and gravity methods. Here is a recently published example from Japan which used seismic interferometry to image an active magma chamber. Magnetic and gravity measurements can be taken from airplanes, which may be a bit safer than being on the ground. If  the magma chamber has magnetic/density properties different from the surrounding country rock, then mag/grav forward/inverse modelling could be used to create a model of the magma chamber geometry.


Is there a formula for heat retained by an atmosphere, based on density and composition? I'm looking for a formula, either precise or an approximation (it's for a video game so it's ok to have somewhat rough numbers), that determines heat retained from the sun by an atmosphere, based on its density and composition (specifically CO2 composition, but bonus points if it factors other things in too).

Does such a formula exist?  Or if not, are there any rule-of-thumb sort of things I could use for estimating "If an atmosphere doubles in density, its heat will rise by X percent" or "If you replace half the CO2 in the atmosphere with O2, your heat will drop by Y percent", etc?

Earth's atmosphere is composed of a number of layers: troposphere, stratosphere, mesosphere, thermosphere and exosphere, ascending in order from the surface.

Each layer has different characteristics and within each layer the temperature profile is different. The red line in the following US standard atmosphere graph shows the temperature profile of the atmosphere.

The temperature profile is complex and is not related to air density (the amber line on the graph) above the tropopause.

There are higher temperatures on the Earth's surface and at the stratopause but low temperatures at the tropopause and mesopause.

As for carbon dioxide, it is fairly well mixed in the atmosphere, particularly at altitude. Concentrations of carbon dioxide vary laterally near the Earth's surface, with the concentrated regions occurring in areas of major human activity, as can be seen from the NASA produced picture below.


Is the area burnt in Amazonas quite smaller than the 2018 California wildfires? I've found this data, which I'm not sure it's right. This article claims the area burnt in Amazon this year is 1,330 square miles (344,468 hectareas) Amazon rainforest fires . And this other article claims the 2018 California wildfires burnt 766,439 hectareas 2018 California wildfires . Is this so? Is the area burnt in Amazon rainforest less than half than the area burnt in 2018 California wildfires?

It is very likely true. Most of the fires shown on TV and in maps are not in Amazonia and not in true rainforest. Quite a lot of them are not even in Brazil. The amount of Amazonian rainforest burning is therefore relatively small, and is due to land clearance and illegal logging where the trees have been cut down and what is left allowed to dry out in the sun and then burned. Out-of-control wildfires are possible in California, but not in true rainforest, which is too damp.  A few very small fires may be due to forest-dwelling natives clearing a small patch and setting fire to it for slash and burn, short-term cultivation. They will abandon it in about 5 years time when the soil is exhausted and the rainforest will gradually take over again.


What is the connection (if any) between jarosite and subsoil biological activity near Spain's Río Tinto? In the short BBC video Spain's otherworldly red river, Ricardo Amils, a researcher in Spain's Astrobiology Center says the following (amateur transcription):

Río Tinto is a peculiar place in our planet that has many similarities with Mars. The most important one is iron. Mars is red because of its iron, and Río Tinto is the red river.
The river’s singular red colour comes from ferric ion, iron oxidised due to the river’s acidity...
Considering the similar geochemistry and minerology, this place is a good analogue to Mars. Life on Mars would probably look like life here.
During his trips to South America, Charles Darwin found life in extreme saline conditions. He then predicted that we would find life in the subsoil. It took us 200 years to prove him right.  If there is life on Mars, as some of us believe, it has to be in the subsoil.
What definitely equialised Río Tinto and Mars was the discovery of jarosite in Mars. This iron and potassium sulphate is produced in great quantities in Río Tinto.
Upon drilling the river’s subsoil, scientists found a great variety of bacteria and microorganisms. These could thrive in extreme conditions, and need no oxygen.

Question: Is it possible to better explain the connection (if any) between jarosite and subsoil biological activity that's hinted at by the video?

The BBC's news videos don't always remain viewable indefinitely, so here are some screen shots for background and context. click for full size

From what I've read so far, it appears jarosite may not be a prerequisite for the formation of certain life forms, instead that it is produced by certain organisms.

  Río Tinto (Huelva, southwestern Spain) is an extreme environment with a remarkably constant acidic pH and a high concentration of heavy metals, conditions generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the Iberian Pyrite Belt (IPB). Fungal strains isolated from the Tinto basin were characterized morphologically and phylogenetically. The strain identified as Purpureocillium lilacinum specifically induced the formation of a yellow-ocher precipitate, identified as hydronium-jarosite, an iron sulfate mineral which appears in abundance on the banks of Río Tinto. The biomineral was characterized by X-ray diffraction (XRD) and its formation was observed with high-resolution transmission electron microscopy (TEM) and scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDX) microanalysis. Jarosite began to nucleate on the fungal cell wall, associated to the EPS, due to a local increase in the Fe(3+) /Fe(2+) ratio which generated supersaturation. Its formation has been also observed in non-viable cells, although with much less efficiency. The occurrence of P. lilacinum in an ecosystem with high concentrations of ferric iron and sulfates such as Río Tinto suggests that it could participate in the process of jarosite precipitation, helping to shape and control the geochemical properties of this environment.

Another reference, states that

  But there is something else about jarosite that makes it interesting. One of the steps in its formation involves combining pyrite (ferrous sulfide) with oxygen. This oxidation reaction can be performed by certain "rock-eating" microorganisms.

  ... And yet, there remains the tantalizing possibility that martian jarosite owes its existence to the martian version of rock-eating microbes. If so, remnants of these organisms may be locked in the mineral.

  ... This is because jarosite on Earth is known to let all sorts of foreign elements incorporate into its crystal structure.

including,

  amino acids, the basic components of proteins

Fate of Lipid Biosignatures in a Mars-Analogue Sulfur Stream

Formation of Rubidium Jarosite During the Microbiological Oxidation of Ferrous Iron at Room Temperature


Where does the Amazon River really begin? Where is the true source of the River Amazon?

Searching Wikipedia, it suggests the River Apurímac has traditionally been considered the source.  However, Google says it is the River Mantaro. In other places it is suggested it is the Nevado Mismi.

So which of these (if any) is the true source of the Amazona? Where is the river born?

From an Earth Science standpoint, it's meaningless to ask about the "source" of a river in this way.  The "source" of a river is the rainfall within its drainage basin, which percolates down into groundwater, and the "river" appears where the land has eroded down below the water table.

The Amazon has an enormous drainage basin:

and every point in it is its "source" in some way.

The trouble with your question is that it asks about the "source" of a river in a way that you first have to define what you consider the "source". Does a stream begin where its name begins? Where water first permanently flows above ground? Most of the time? Some of the time? Anywhere there's a big enough pile of wet leaves?

In Brazil, the part of the river above its confluence with the Rio Negro at Manaus has its own name -- the Solimões, so you could say the "Amazon" proper begins at Manaus. But this is thousands of miles from the river's farthest upper reaches.

The Wikipedia article on the Amazon River has the following to say about its "farthest source":

  The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon’s most distant source, until a 2014 study found it to be the Cordillera Rumi Cruz at the headwaters of the Mantaro River in Peru. The Mantaro and Apurímac join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon.

But because a tunnel associated with the Tablachaca Dam diverts water away from a big loop of the Mantaro River, effectively shortening it, all you'll ever get now is an argument about what's "really" the furthest source.


Why clouds are not moving in NASA's video of the Moon passing in front of the Earth? I recently saw a short video from NASA. It shows the moon passing by the Earth as it rotates.

NASA link: From a Million Miles Away, NASA Camera Shows Moon Crossing Face of Earth.

The video itself looks quite fake, but that can probably be attributed to the fact that it was reconstructed from sensor data as opposed to a regular camera.

My question is, why do the clouds not appear to move at all? According to the website, the images span approximately 5 hours.

There are a lot of people online saying the video is fake. I believe the Earth is a globe, but I can see why people have their doubts about this particular video.

The clouds can be seen moving but of course it's subtle at first glance.

Frame 16:

Frame 20:


MS in Geosciences With Concentration in Environmental Geosciences Degree Outlook I am considering a MS in Geoscience but am curious with the naming conventions associated within the fields of geology. Is Geoscience similar, or interchangeable with geology? Yes, I would be new to the field. I would like to couple my aviation (meteorology, etc.) schooling with a science-rich program. Everyone appears to be professionals on here and would likely know the answer.

Is Geoscience similar, or interchangeable with geology?

Geology is, strictly speaking, a subset of the wider field of geosciences. However, this probably doesn't mean much when people look at the name of your degree or the name of the department of school that awarded your degree. As farrenthorpe said in the comments, what's important is what you do in your research.

Common names for degrees (or departments) could be geoscience, geology, earth science (like the place when I am at the moment), earth and marine science, geological and environmental science (like the place where I did my BSc and MSc at). Doesn't matter. You are probably looking for something in the general field of atmospheric sciences, and each of variations above may or may not include it. Find schools that you're interested in and check each case on its own.


How does liquid iron create a magnetic field? I'm pretty sure metal loses more of its structure as it heats up, so...how does the difference in rotation of Earth's liquid inner and outer core generate any kind of magnetic field? Why wouldn't the magnetic field be even stronger if those two layers weren't rotating?

It seems your question assumes that Earth magnetic field is caused by natural magnets inside the Earth. Instead, the magnetic field comes from the movement of charged particles.
Any electrical charged particle in movement generates a magnetic field (see Biot-Savart law and Ampere law), hence, thanks to the movement of particles in a liquid mantle we have a magnetic field. Obviously, particles must have electrical charge, which is more common in metals.
If mantle turns solid, movement is gone, and the magnetic field reduces its strengh.


Geomorphology of Mountains With Wind only Erosion I am curious what mountains would look like if erosion occurred almost entirely by wind. Specifically, I am curious of how granite mountains would look on a "snowball" terrestrial-sized xenoplanet.

On a "snowball" world, the planet is earth sized and retains water but it lies outside its sun's "goldilocks zone" and is to cold for liquid water. Ocean's freeze over to a deep of several kilometers with only deep pockets kept liquid by concentrated minerals and vulcanism.

With no liquid water there will be no liquid erosion and no ice fracturing. The only moisture at all in the air will come from sublimation so very little ice will be deposited at altitude and it likely won't form glaciers or otherwise contribute to erosion.

At lower altitudes, very slow moving glaciers will probably perform most erosion but at altitude it will be erosion from wind carrying water and CO2 crystals as an abrasive.

On Earth, erosion from water causes convex (wide rock, narrow erosion channel) while glaciers causes concave (narrow rock, wide erosion channel.) Hard brittle rock such as granite suffers ice fracturing leaving a jagged vertical channels with overall angular features.

In dry areas on Earth erosion creates rounded, fluid structures like stones shaped by a stream. But I am unclear of how much that is a feature of wind erosion and how much a feature of softer sedimentary stones. It looks like Mars, where erosion is primarily wind driven, does have more rounded and less jagged mountains than on Earth but I don't know about the suspected composition of the those mountains.

If granite wears from the wind, does it round off or does it's internal structure cause it to fracture even without water?

Thinking about it another way, if the Earth completely froze over, what would the Rockies, Andes or Himalayas look like after a few million years of wind only erosion?

You do have an earth analogue for this. The Namib Desert in Namibia has been a desert for the past 2 million years with very little precipitation. Also the Atacama Desert is hyperarid since more than 25 million years.

Mars is probably a planet that has below freezing temperatures for million of years, with only wind as an erosional process (apart of a few gravitative processes).

Granite is weathering in roundish forms, as it takes no clear direction from crystallisation. Usually the granite erodes in arid landscapes because of temperature changes and tiny differences in moisture and salts. In a completely frozen plant without a strong atmosphere you would probably still get round forms like Inselbergs.
Furthermore there are of course different kind of forms of wind erosion resulting in strange looking shapes.

High mountain ranges on earth are always limited by erosion from water or glaciers (frozen water) in their growth, as there is more precipitation with altitude.
To get sharp mountains you will need plate tectonics, which will result in the formation of an atmosphere and the release of heat and water (I assume the formation of an atmosphere since platetectonics are associated with volcanismn, which will lead to water and other chemicals like CO2 being released). Thus you will get erosion from water. If the plate tectonics stop and the atmosphere disappears, the mountains will stop growing and there is no moisture left for erosional processes. Then erosion by wind will be the primary geomophological process and the planet could look like Mars.

(I admit this is highly speculative, but the question is speculative in itself.)


Why do values stored in data files, such as climate model output, appear to be high? I'm in doubt of some values for future scenarios of climate change that were downloaded from http://www.worldclim.org/version2. For example, the NCAR circulation model for bio_5 variable at optimistic scenario (Max Temperature of Warmest Month) to 2050 is 335.33.

Other similar calculations with other scenarios, circulation models and another future year, returns values ranging from 55 to 103 for the max temperature of warmest month. This appears wrong. Am I reading the data correctly?

My professor gives the solution, as we can see at the site were the climatic variables came from http://www.worldclim.org/formats1:

  Please note that the temperature data are in °C * 10. This means that a value of 231 represents 23.1 °C. This does lead to some confusion, but it allows for much reduced file sizes which is important as for many downloading large files remains difficult. The unit used for the precipitation data is mm (millimeter).

(Edited in by Gerrit): storing (climate) data with offsets and scale factors to reduce file size is common practice, as scaled integers can easily be less than half the size of floats.  When data are stored in standard formats sch as NetCDF or HDF-5, there is probably a variable attribute documenting this.  When data are stored in a homegrown format, check the documentation carefully for any mention of offsets and scale factors that need to be applied.


Why was the sky SO yellow? Today, I was coming back from music school, and it was raining heavily. An hour after I came back, the sun started coming out from one side, and the sky wa very brighr yellow. The lighting effects that came through all my windows were spectacular.

Here are some images:

I appreciate any explanation how phenomenon like this can occur and why.

In this case I'd say it's a combination of Rayleigh scattering,
Mie scattering and the angle of the sun.

Rayleigh scattering is related to the chemical composition of the atmosphere and occurs when the particles causing the scattering are smaller in size than the wavelengths of radiation in contact with them (this is why the sky appears blue most of the time). The yellow sky in this question is likely mostly owing to Mie scattering. Mie scattering is caused by pollen, dust, smoke, water droplets(the most likely culprit in this case), and other particles in the lower portion of the atmosphere. It occurs when the particles causing the scattering are larger than the wavelengths of radiation in contact with them. The angle of the sun and Raleigh scattering may also be at play, when the sun is low in the sky sunlight passes through more air than when the sun is higher in the sky. More atmosphere means more molecules to scatter the violet and blue light away from your eyes. If the path is long enough, all of the blue and violet light scatters out of your line of sight. The other colors continue on their way to your eyes. This is why sunsets are often yellow, orange, and red.


Do earthquakes produce folds on rocks? Earth rocks are frequently folded at surface.

  Folds in alternating layers of limestone and chert in Crete, Greece.

  Source: commons.wikimedia

Are earthquakes the main mechanism producing the folds?

If so, have ever geologists observed the development of a fold after an earthquake?

No, earthquakes are sudden, often very energetic events which produce faults and discontinuities. There is a sharp break in the strata when subjected to a powerful earthquake. The folding of strata is a much more gradual process, where rock deep underground is subjected to enormous lateral pressure over millions of years. This pressure is caused by plate movements (continental drift). Earthquakes have a variety of causes, but the most violent ones are also caused by continental drift as one plate slides past another along a fault line. The San Andreas Fault in California is an example of this. One of the plates is moving, but friction holds it in place for a while, sometimes for many years. Pressure builds up until suddenly the friction force holding it in place gives way, and there is an earthquake as the moving plate slips forward for a few metres. For these reasons, geologists have never seen a newly created fold after an earthquake. It is impossible for one to form in so short a time.


Does hydroxyl radical chemistry in air quality models create numerical stability problems? Atmospheric mixing ratios of the hydroxyl radical have relatively short lifespans (on the order of microseconds). When modeling air quality or the weather, the time step is usually much larger than the the half life of hydroxyl. How is this computation numerically stable? Is the problem of numerical stability simply ignored?

The hydroxyl radical chemistry is not modeled explicitly in air quality models, so numerical stability is not an issue.  Instead, OH is held in pseudo-steady-state.  For instance, see CMAQ's documentation which states:

  In CMAQ's gas phase, OH is assumed to be in pseudo-steady state, and it is not a transported species.  This is because hydroxyl radical reactions tend to be catalytic (e.g., consumption and production). In the aqueous phase chemistry, OH is absorbed by cloud water and in an open cloud model (i.e., the design approach currently employed), absorbed species (e.g., OH) would be replenished via gas-to-cloud partitioning. However, due to operator splitting, aqueous and gas-phase chemistry are not solved simultaneously. To account for this and other uncertainties in predicted OH aqueous phase concentrations (e.g., neglect of production reactions (H2O2 + hv -> 2 OH) not currently implemented in aqchem), a steady-state assumption for OH is adopted in the aqueous chemistry routine.

Typically, if you are trying to model something like the hydroxyl radical, you would use a box-model like MECCA, not a chemical transport model.


Why did a branch against a window prevent condensation? Last night was pretty chilly here in South East Queensland, Australia.
We woke this morning to condensation on the bedroom windows but noticed something curious.

Where a small branch was touching the window there was no condensation.  What caused this?

The branch block outgoing infrared radiation and reflect some of it back to the window this will keep the temperature slightly above the condensation point.
Infrared radiation is the same as heat radiation.
Most objects will block and reflect infrared radiation and this is why dew does not form under a tree or under different types of roofs and objects partially covering the ground.
The CO2 in our atmosphere has a similar effect,absorbing and re emitting the infrared radiation keeping earth warm at night,had it not been for the different greenhouse gasses the temperature changes during the day night cycles had been a lot larger.


Does PV=nRT mean that isobars are also isotherms? Does the ideal gas law, PV=nRT, mean that isobars on a map of surface conditions are also isotherms?  Is there a way to intuit isotherms from isobars, and vice versa?

No. After a bit of mathematics, and the inclusion of water vapor, you can also get $P=\rho_d R_dT_v$, where $\rho_d$ is the dry air density and $R_d$ is the specific gas constant for dry air, and $T_v$ is the virtual temperature. So isobars are more than just isotherms- they are also dependent on density and water vapor. Check out Wikipedia's derivation for the proof that $PV=nRT$ is the same as $P=\rho RT$, and then use the fact that $\rho$ has both dry air and water vapor, to get $P=\rho_d R_dT_v$.


How does this melted-wax erosion pattern form in sandstone? How does this kind of erosion pattern that looks like melting wax form in sandstone? Can you describe the kinds of processes and kinds of rocks that are needed for this? I've seen it in Nevada, but this example is from Jordan.

(Image by Ethan Welty)

Differential erosion, the "wax-drips" have been hardened by chemical deposition, usually by calcium salts, washed down from the soil at the top of the cliff. There are different mineral deposits that can cause this effect including but not limited to calcite, silica, iron, manganese, fine organic matter, alumina, and fine clay, to name a few, anything that can be deposited between the grains of the sand stone will do really. These minerals flow into the sandstone when wet and as the surface dries they act as a cement increasing the durability of the sandstone in the areas that have been wetted by the mineral rich water. The wind then erodes the surface of the rock and because the cemented material is harder it cuts more deeply into the rock between the water pathways.


How isotropic is the Earth's inner core boundary? Often, in texts (particularly for schools etc) depict a smooth spherical isotropic boundary between the inner and outer core, as shown in the image from this USGS public education page:

The inner core boundary is between the inner and outer core layers.

How isotropic is the Earth's inner core boundary?

Related questions

How can we guess the size of the Earth's inner core(and what it's made of)?

Why does seismic activity shed light on the inner core rigidity?

Why is Earth's inner core solid?

These are related but this question is about the nature of the boundary between the inner and outer core.

Some recent geophysical observations by Dai et al. (2012) (1) showed that compressional seismic waves reflected off the inner core boundary (ICB) exhibit significant variations in:

travel time, of the order of -2 to 2.5 seconds.
amplitude, by up to a factor greater than 4 (up to a factor of 6 oberved by Li et al. 2014 (2)).

These observations, according to Dai et al. (2012) (1) suggest that the ICB is irregular, with possible height differences of up to 14 km, across a distance of 6 km, and 4-8 km over a distance of 2-4 km.

Dai et al. (2012) (1) suggest that these variations are indicative of thermochemical deformation of the ICB. An alternative explanation presented by Li et al. (2014) (2), after numerical analyses of seismic traces, taking into account the effects of shallower structures, suggest that the ICB being a several-kilometre-thick 'mushy' layer indicative of a gradual transition between the inner and outer core.

The actual nature of the ICB is not completely understood, a recent theory by Vamos and Suciu (2014) (3) suggest that the anisotropy of seismic observations could be a result of a de-centred core due to interactions with the flow and the magnetic field inside the outer core.

Observations by Wen (2006) (4) found that seismic traces from the same location taken at different times posessed different return times in the space of ~10 years, suggesting that deformations (as later described by Dai et al (1)) occur on a differentially rotating inner core, alternatively, Wen (4) suggests that the size of the inner core changes with time.

References

(1) Dai et al. 2012, Irregular topography at the Earth’s inner core boundary, PNAS

(2) Li et al. 2014, Notes on the variability of reflected inner core phases, Earthquake Science

(3) Vamos and Suciu 2014, Geophysical implications of a decentered inner core, arXiv.org

(4) Wen 2006, Localized Temporal Change of the Earth's Inner Core Boundary, Science