21 votes
Accepted

What factors determine the number of Hadley cells for a planet?

Well for one, this will surely be the speed of planetary rotation and the wind speeds your atmosphere can generate in North-South-direction. In my understanding those cells form as N-S winds flow and ...
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16 votes
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Why are deserts mostly located on the western side of continents?

Some of the driest deserts on Earth occur in the western side of continents and they are called Coastal Deserts. Examples of such deserts are the Atacama desert (Chile, the driest desert on Earth), ...
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  • 14.7k
12 votes

Why does the Hadley cell descend at 30 degrees?

The Hadley cell was proposed and works only for a non-rotating earth. When we consider the earth's spin, we have to consider the Coriolis force as well. Because of this force air cannot travel in one ...
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  • 745
10 votes
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How long does it take for the atmosphere to mix?

The time scale of interhemispheric tropospheric transport is in the order of one year (Chapter 4 of the book Introduction to Atmospheric Chemistry written by Daniel J Jacob). This is not an exact ...
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  • 1,662
9 votes
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Why does the meandering pattern of the jet stream itself propagate?

I wouldn't characterize the movement of the jetstream as a "less well known" problem, at least not to anyone who has sat through a synoptic meteorology class. The jetstream from a dynamic point of ...
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  • 13.9k
9 votes

Is everything affecting everything on Earth?

Do you know what the weather will be in four hours time? You can probably make a very confident guess. How about this time tomorrow? You can probably make a reasonably confident guess. How about this ...
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  • 4,060
9 votes

Why is Egypt so dry?

If you take a look at the atmospheric circulation pattern, the Hadley Cells in particular, they tell the story. The northern edge of Africa is on the descending edge of a Hadley Cell, which means ...
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  • 1,027
8 votes

Why are deserts mostly located on the western side of continents?

Because of the Coriolis Effect, the prevailing winds on the earth between about the Tropic of Capricorn and the Tropic of Cancer go from the East to the West (knows as the Trade Winds). To get to the ...
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  • 2,563
7 votes
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How to install ESMF and ESMFPy in Ubuntu using gfortran, gcc, python?

First download the esmf tar file from http://www.earthsystemmodeling.org/esmf_releases/public/ESMF_7_1_0r/reg/ESMF_Framework_Down.html Then install netcdf library and gfortran compiler using ...
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7 votes
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Why do the dry and moist adiabatic lapse rates converge with height?

If you look closely at the diagram you'll notice height isn't the primary cause for the convergence between the adiabats, though it is the driver. Note that toward the upper right there is still ...
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7 votes
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Relation between direction of shear and tropical cyclone formation

The direction of the vertical shear plays a large role in cyclogenesis, where easterly shear tends to enhance the formation of cylones and westerly shear tends to suppress it (Tuleya and Kurihara, ...
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6 votes

Is everything affecting everything on Earth?

The media loves the butterfly effect, but they also love to mis-portray what it means. When Lorenz gave his talk "Predictability: Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in ...
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6 votes
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Why does the El Niño Stop?

I think it is important to think of the El Niño as just one of the components of a large scale global atmospheric-oceanic phenomenon known as the El Niño and the Southern Oscillation (ENSO). ENSO ...
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5 votes
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Monsoonal interactions with mid latitude disturbances

Here are two parts of an answer, but this is by no means complete. Most monsoonal research is focused on explaining the monsoonal passage through the plains of the Indian subcontinent. Very few ...
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  • 6,208
5 votes
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How do academics/institutions run large climate simulations given the computing challenges?

This question is a little vague, with multiple aspects, but I shall do my best. Computing resources Some universities have their own clusters or supercomputers. But many countries also have regional ...
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3 votes
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How to derive the total potential energy of the atmosphere?

First, let's acknowledge this fact: $$c_p=R+c_v \tag{1}$$, where $R$ is the specific gas constant. This means that $x=R/c_p$. Rearranging the equation, we can see that $$P+I=\int{c_p\left(\frac{P}{P_{...
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3 votes
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Why is the pressure on the poles higher in Summer and lower in Winter?

My answer will only relate to the question in the title: Why is pressure on the poles higher in summer and lower in winter? Due to the axis tilt of the earth the winter hemisphere gets less heated by ...
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  • 776
3 votes

Latent heat and global circulation

Latent heat is released when water vapor turns to liquid\solid water. So latent heat is released where there is precipitation. So you're looking primarily at places where there is lots of moist ...
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3 votes

How do academics/institutions run large climate simulations given the computing challenges?

Another UK perspective here to supplement Semidiurnal Simon’s answer (which reflects my experience too). The UK research community is dominated by a single family of models known collectively as the ...
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  • 3,133
2 votes

Why does the Hadley cell descend at 30 degrees?

Air usually subsides at 30 degrees because at that latitude it is cool enough to allow it to sink. Your question on why air rises at 60 degrees; this is obviously not because of convection since ...
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2 votes
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How is there enough $\ce{O2}$ in the atmosphere to breathe if you are in a desert with no plants?

The short answer is, $\ce{O2}$ is all around us! You aren't breathing the $\ce{O2}$ that the trees next to you are respirating (at least not much). No matter which way the wind is blowing, you ...
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2 votes

How is there enough $\ce{O2}$ in the atmosphere to breathe if you are in a desert with no plants?

Look at it this way: According to the American National Center of Atmospheric research, the Earths atmosphere weighs 5.148 x 10^^18 kg., and that atmosphere is composed of about 20.8 to 20.9% oxygen (...
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2 votes

Latent heat and global circulation

Latent heat release is critical for the general circulation, in particular the tropical overturning circulation (Hadley & Walker circulations). The release of latent heat is the dominant diabatic ...
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  • 49
2 votes
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Temperature Advection using finite differences with gridded data

When I look at problems like these I first check to see if there is a well tested and well documented implementation already rather than reinventing the wheel. In this case MetPy temperature ...
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  • 6,208
2 votes

How to search for the nearest non nan value in 2d xarray dataset

If I were you, I would exclude the NaN values and then perform gridding on the resulting irregularly spaced data. There are already the tools to perform this in Python and using the library SciPy ...
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  • 292
2 votes

How to install ESMF and ESMFPy in Ubuntu using gfortran, gcc, python?

Actually, you probably shouldn't install it. If you're comfortable using Linux, then you would be better advised to use the docker container instead, with it already installed. That way your system ...
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2 votes

How to convert the units of specific cloud liquid water from ERA5 (kg/kg) to kg/m2?

I got the solution https://www.researchgate.net/post/How_to_convert_the_units_of_specific_cloud_liquid_water_from_ERA5_kg_kg_to_kg_m2 and https://www.nwpsaf.eu/site/download/documentation/rtm/...
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1 vote

Vertical air speed

That's... a pretty specific question. Well, we start with making assumptions. Let's write the continuity equation with the Boussinesq approximation: $$\frac{\partial \omega}{\partial P}=-\frac{\...
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1 vote

Can we see the circulation cells in wind maps?

Yes, the wind cells are just a toy model, where we can suppose that the homogenity of the Earth and other things. But there are other things and Earth isn't same on the all points, so the ...
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  • 618
1 vote

Temperature Advection using finite differences with gridded data

I've come to a solution. I have followed @gansub's suggestion to check what there is already there, before reinventing the wheel. I found MetPy's code very (too) well structured, so the code for ...
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  • 587

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