gerrit
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How do 'greenhouse gases' let heat in, but not let it out?
78 votes

In a nutshell: The radiation that enters is shortwave radiation from the sun. Solar radiation is dominated by visible (as well as UV and near infrared) radiation with a wavelength mostly between 0.2 ...

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Debunking scientific paper "Has global warming already arrived?"
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35 votes

The comment is saying that the authors are making a fallacy as follows: Temperature increase will be associated with an increase in tropopause height. Using instrument/dataset X, we fail to measure a ...

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Could the Earth's core lose its heat?
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32 votes

Part 1, see Neos answer. Earth will lose its heat no matter what we do, and our extraction of geothermal energy is insignificant (Wikipedia quotes a BP figure of 11.4 GW electrical, 28 GW heating). ...

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Why clouds are not moving in NASA's video of the Moon passing in front of the Earth?
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27 votes

They are moving, but not fast enough to notice at the distance shown. From the NASA page: These images were taken between 3:50 p.m. and 8:45 p.m. EDT on July 16, showing the moon moving over the ...

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Is it true that a butterfly flapping its wings can result in a tornado in a distant location?
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24 votes

The butterfly is a colourful illustration of Chaos Theory, and the word butterfly came from the diagram of the state space (see below). A system that is chaotic is extremely sensitive on its initial ...

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How is ocean salinity measured from space?
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23 votes

In a nutshell: The instrument measures microwave radiances (after calibration) If we know the sea surface temperature, we can use radiances to calculate emissivity. The emissivity at 1.4 GHz is ...

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How will cloud feedback effects on the climate change as the result of global warming?
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20 votes

We don't really know. Climate models agree that the feedback is profound. Significant. Unfortunately, they do not agree about the magnitude of the feedback. Nor about the sign. The problem is ...

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How bad is geo-engineering?
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17 votes

The bad part about geo-engineering are the unknown unknowns, to paraphrase a certain US politician. Our climate models are wrong. All models are wrong, but some are useful.. Our models are useful, ...

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If 75% of radioactive material remains, how many half-lives have elapsed?
15 votes

You can use simple logarithms to calculate the answer. The number of half-lives that have elapsed can be calculated with $$ - \frac{\log{f}}{\log{2}} $$ where $f$ is the fraction that remains. So ...

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What are the major differences between weather models and climate models?
15 votes

This answer is not complete, but it is a start. One of the most significant differences is: Weather models use measurements, whereas climate models do not Put another way: a weather model is an ...

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How is it possible to use up the water in a region?
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14 votes

You're making a mistake, at least for the second case: In the second case, the water ends up as rain, presumably within a few hundred kilometers of the evaporation point. You cannot model a dry ...

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Could the earth be much older than the currently accepted number?
14 votes

The age of the solar system is 4.6 billion years. We know that because almost all meteorites are 4.6 billion years old¹. Therefore, that puts a very solid upper boundary to the age of the Earth. ...

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What determines how fast clouds move?
14 votes

Cloud particles are suspended in air, and their movement is governed by: Wind; whichever way the wind blows, the clouds go (with some exceptions such as lenticular clouds; thanks jamesqf comment). ...

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Are there water molecules in the oceans which will almost never fall down as rain?
14 votes

Never is a very, very long time. Almost never is a vague term. The age of deep ocean water has been studied with both models and observations, and both indicate a lower limit age in the order of ...

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Is the atmosphere becoming thicker?
14 votes

No, the atmosphere is not becoming thicker. If anything at all, the atmosphere is getting thinner, but only on very long time scales. Planet Earth very slowly loses parts of it atmosphere due to ...

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Could an icy/extremely-cold asteroid/comet ever strike and cool the Earth?
13 votes

No, it's not possible to cool the Earth with an asteroid impact. The mass of any asteroid that could hit the Earth is far too small to be a heat sink. The asteroid that killed the dinosaurs had a ...

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How does the pole-to-equator temperature gradient scale with height contours?
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13 votes

It depends on the season. The figures below shows zonal mean temperature for June-July-August from ECMWF ERA-40 reanalysis. As you can see, at 100 hPa, the equator is actually colder than the sunlit ...

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How can I estimate a 2 m temperature from / in an atmospheric model?
13 votes

Your premise is incorrect. Numerical models normally have: A full temperature profile A specific field for the 2 metre temperature A specific field for the skin temperature For example, see ERA-40 ...

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Is there a map that displays every country at its correct relative size?
12 votes

Yes. Every equal-area map displays all countries (and other areas) in their correct relative size. Inevitably, they don't show the correct shape (unless you're looking at a globe). Personally, my ...

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Why are the clouds white and Australia black in weather satellite infrared images?
12 votes

I had a very similar question in a job interview! The only difference is that it was an image from SEVIRI on Meteosat. The imager on HIMAWARI is called the Advanced Himawari Imager (AHI). The AHI ...

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Is the epicenter always directly above the hypocenter?
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12 votes

By definition, the answer is yes: epicenter, the point on the earth's surface vertically above the focus of an earthquake, or the Hypocenter according to Merriam-Webster or a many other sources.

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Can the previous weather be computed from the current situation?
12 votes

Validation is done by hindcasting, not by reversing the time axis, which seems to be what you're asking about. In hindcasting, we take the state at some time in the past, apply our weather models to ...

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How do weather models work?
12 votes

This is not a complete answer. One aspect of weather models consists of Data assimilation or 4D-var. I agree that they are amazing, and the question how do they work is too broad to be answered. So ...

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How to calculate relative humidity?
12 votes

No, this is not enough. Relative humidity is defined as the water vapour partial pressure relative relative to the saturation water vapour pressure: $$ \phi = {{e_w} \over {{e^*}_w}} $$ where ${e^...

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Does anyone know of a comprehensive listing of geostationary weather satellites?
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12 votes

The WMO OSCAR database is a list of all Earth observation satellites¹. The resulting table can be sorted by orbit type, status (inactive/operation/planned), agency, and other aspects. From their own ...

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Why have "ozone-depleting substances" led to a third of all global warming and half of arctic sea ice loss?
11 votes

The Global warming potential (GWP) describes how much global warming a particular gas may induce in a particular time period. It is often expressed in terms of CO₂-equivalent. The best known ...

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Are average daily temperatures affected by DST?
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11 votes

They compensate for DST. That is, for any daily measurement, they use the same universal time every day of the year. If they take a measurement at 7:00 local time in summer, they will take the same ...

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Why does winter get colder after the solstice?
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11 votes

Primarily because of inertia. This phenomenon is called seasonal lag. It is true that the December solstice is the moment that the northern hemisphere gets the lowest total amount of insolation. ...

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How much land does it take to support New York City?
11 votes

The average ecological footprint of a US citizen has been estimated as 8.00 global ha. Multiplying 8.5 million by 8.00 hectare gives 680,000 km², or around 5 times the area of New York state. Of ...

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How were we able to measure carbon dioxide levels in earlier climates?
11 votes

One method is through ice cores from the worlds ice caps. Each year, as small amounts of snow accumulate on ice caps such as on Antarctica and Greenland, bubbled of air gets trapped. As we drill ...

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