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15 votes
Accepted

Why (actually) is the night sky so bright in the city? How far up is that happening?

What's actually happening is scattering of light, both off of aerosol particles and nitrogen and oxygen molecules. For a review of quantitative models of light pollution as a function of distance ...
DavePhD's user avatar
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9 votes
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Would covering part of Lake Mead with large sheets of bubble wrap reduce the amount of water lost to evaporation?

Something similar has been done with plastic balls. I'd guess they're much easier to manufacture, since it doesn't have to be a continuous sheet. It sounds like there is some local water savings, ...
damp_civil's user avatar
7 votes

Time for water vapor to generate more greenhouse effect than latent heat?

This is actually hinted at in the typical Trenberth energy budget diagram for the Earth: The $86.4\mathrm{\frac{W}{\,m^2}}$ is that energy movement up into the atmosphere from vaporization. The $340....
JeopardyTempest's user avatar
7 votes

How to calculate water vapor flux divergence from temperature, relative humidity, u wind and v wind?

The formula for moisture flux is $$q\vec{V} $$ where $q$ is the water vapor mixing ratio, which can be found using mixhum_ptr and $\vec{V}$ is the velocity. Therefore the divergence of the moisture ...
BarocliniCplusplus's user avatar
5 votes
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How to interpret the negative (actual) evapotranspiration values?

Negative values for the ET, both potential and actual, usually refer to condensation. See also "ERA5 mean evaporation rates data - Why is that negative?" Regarding the ability of the ...
Nemesi's user avatar
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4 votes
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How much water is the atmosphere receiving

About 30,000 tonnes of extraterrestrial material arrives on earth every year, mostly in the form of submillimeter dust. Unfortunately, these micrometeorites are pretty dry. The wettest meteors might ...
David Bailey's user avatar
  • 1,018
3 votes
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How is weather formation prevented in the stratosphere?

By that principle, I would expect water from the troposphere to diffuse into the stratosphere, where water content is significantly lower than in the former. You are forgetting that water is not ...
David Hammen's user avatar
  • 23.7k
3 votes

Cooling effect by evaporation

Someone (Casey?) can probably provide a fuller answer, but the basic idea is that ice molecules are kind of locked into place by the molecular structure of the ice crystal, and can't vibrate very much....
Gordon Stanger's user avatar
3 votes

How much fresh water could be produced by pumping warm humid air through a pipeline up to the top of a mountain?

All kinds of additional problems too: Your given values equate (RH calc)(dewpoint calc) to a dewpoint of 73°F, rare to find (mostly towards summer in limited areas... for the US: mostly the Plains/...
JeopardyTempest's user avatar
3 votes
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How much fresh water could be produced by pumping warm humid air through a pipeline up to the top of a mountain?

Using the relative humidity and temperature, the g/kg ratio of water to dry air can be calculated. Using an online rh calculator, a relative humidity of 70% and a temperature of 302 K at 1 atm ...
Stevan V. Saban's user avatar
2 votes

Would covering part of Lake Mead with large sheets of bubble wrap reduce the amount of water lost to evaporation?

Evaporation requires energy (~680 kWh / m³ water) and as always this is mainly supplied by the sun. At Lake Mead I estimate ~ 2000 kWh/m² per year of incoming solar radiation. A highly reflective ...
Rammstein's user avatar
  • 143
2 votes
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Water vapor content versus specific humidity

For a study relating to rainfall, I would be inclined to look at total column water vapour (TCWV), also known as integrated water vapour (IWV) or precipitable water. They're all (more or less) the ...
gerrit's user avatar
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2 votes
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Has there ever been a study done on the effect of steam/thermal pollution on climate

While the effect might be measurable (just barely) it's small. We add about 30 billion tons of CO2 to the air every year. About half of that gets absorbed into the oceans (give or take), the ...
userLTK's user avatar
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2 votes
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Is there really precipitation on Mars? Does frost count?

See this answer. Actually already snows on Mars. The snow, made of carbon dioxide, has been observed and studied by orbiting spacecraft. Aside from the different chemical composition from the stuff ...
Oscar Lanzi's user avatar
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2 votes

What does supersaturation with respect to ice mean?

I can identify two parts of how this may be confusing. The first is vapor pressure with respect to ice, and the second is supersaturation. First, let's look over the equation for phase transitions. ...
BarocliniCplusplus's user avatar
2 votes
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What does supersaturation with respect to ice mean?

The saturation vapour pressure defined by the American Meteorological Society: The vapor pressure of a system, at a given temperature, for which the vapor of a substance is in equilibrium with a ...
gerrit's user avatar
  • 11.7k
2 votes
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Does saturation mixing ratio change during adiabatic ascent/descent?

The saturation mixing ratio is not how much water vapor the air has in it... but how much it could have, based upon the temperature. Since adiabatic ascent/descent means cooling or heating, the ...
JeopardyTempest's user avatar
1 vote
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How does water vapor cool the troposphere?

Let's for a moment think about the troposphere consisting of stacked layers. The anvil clouds can only be found in the upper layer of the troposphere, since this is where they have to extend ...
Joscha Fregin's user avatar
1 vote

Yearly changes of solar irradiation and atmospheric feedback

I think your ~2 figure for CO2 greenhouse amplification is in error. * In the last 200 years it's gone from the high 280s to low 400s. This is an increase of about 50% Good thing it's not linear as ...
Sherwood Botsford's user avatar
1 vote

Does the gravitational pull of the moon affect the composition of Earth's atmosphere?

The long term influences upon the Earth's atmosphere are additions, subtractions and internal variations. The additions consist of gravitational attraction of passing gas molecules from space, which ...
Gordon Stanger's user avatar

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