# All Questions

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13k views

### What is the difference between eluvium and alluvium?

I was reading about kimberlite on Wikipedia and it mentioned eluvium. I've heard of alluvium, alluvial fans, alluvial deposits, etc. However, when I looked up eluvium, it sounded exactly like alluvium....
774 views

### Are there secondary causes of sea level change?

Aside from the fraction of water stored as ice on land and temperature of the water, are there other factors that change sea level, and if so what are is the magnitudes of the these changes? For ...
865 views

### What processes produced the basalt columns of the Giant's Causeway?

The Giant's Causeway is, according to the Wikipedia page was formed during during the Paleogene Period, Antrim was subject to intense volcanic activity, when highly fluid molten basalt intruded ...
15k views

### What caused the bend in the Emperor/Hawaii chain of islands, 45 million years ago?

What caused the bend in the Emperor/Hawaii chain of islands, 45 million years ago? Has there been any updates to this mystery I am unaware of? Are there any new theories that could potentially ...
987 views

### What are these lake-like blue patches in the desert, visible in satellite image?

I found some blue patches in the Arabian desert in Google Earth. It looks like as if they were lakes with sand dunes rising out of the water. But there isn't water in the desert, at least not this ...
6k views

### Why does air subside in the Eye - the lowest pressure area of a tropical cyclone?

A low pressure area is associated with rising air while a high pressure area is associated with subsiding air. The best explanation I could come up with is either the cyclone is an exception or the ...
2k views

### How to read a NetCDF4 file in Matlab?

I have downloaded the sea surface temperature data from the Ocean Color website, the file is in NetCDF format and contains no of geophysical_data variables like sst,...
526 views

### Why cannot people burn all the atmospheric oxygen? [closed]

We are told that photosynthesis, developed a couple of billion years ago has produced all the atmospheric oxygen. I wonder, why did the process stop? Why do modern plants prefer to recover the entropy ...
11k views

### Why is there a seasonal cycle to the amount of CO2 in the atmosphere?

I'm doing some homework on the increase of $\mathrm{CO}_2$ in the atmosphere. On one of the graphs it shows the amount of $\mathrm{CO}_2$ peaks in May and has a low in November. Why is this? Shouldn't ...
493 views

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

So global warming will increase the tropospheric temperatures, which, in turn, would make the clouds higher than they otherwise would be. And higher clouds (especially cirrus clouds) tend to trap in ...
49k views

### Are the processes of the rock cycle currently in dynamic equilibrium?

The standard representation of the rock cycle usually looks like this: Does each stage of the rock cycle currently balance? That is, are the various processes in dynamic equilibrium, so that the ...
2k views

### How is the equilibrium of 21% oxygen in Earth's atmosphere established?

The atmosphere is 21% oxygen. I assume that there must be an equilibrium between processes that produce oxygen (e.g. photosynthesis) and those that consume oxygen (e.g. aerobic respiration). Moreover,...
482 views

### What causes the beautiful Auroras on the north and south magnetic poles?

What is the scientific reason for the majestic sights of the northern and southern lights, otherwise known as Auroras near the magnetic poles, and why do the northern lights differ from the southern ...
20k views

### Why do gold deposits form only in certain areas of the earth?

In the map above you can find that most elements are spread evenly throughout Earth's crust and that they are available all around the Earth. However, gold can only be found in certain areas of the ...
2k views

### How could this pyramidal Mountain have been formed?

How could this pyramidal peak have been formed in Antarctica? Little is known about it as far as I know but what is known is that its miles away from any existing plate boundary and its shape is also ...
154 views

### How would weather change on a tidally-locked terrestrial planet?

On Earth, weather is very much affected by the Earth's rotation around its axis and around the Sun. Even locations that are almost on the equator do have strong annual variations in precipitation and ...
1k views

### Deciphering NCDC data

I need US monthly climate data for the years 1992-2012. It would be great to get down to a county level, but by state would be just fine. Every site that I go to inevitably kicks me to the NCDC, but I ...
142 views

### Relationship between tides and earthquakes

Ide et al. (2016) suggest that earthquakes (especially those of high magnitudes) are more probable during periods of high tidal stress (during full and new moons). While they show a comprehensive ...
732 views

### Causes of fluctuations in atmospheric oxygen in past 300 Mya

I have two questions based on the history of atmospheric oxygen levels depicted below. Source: https://commons.wikimedia.org/wiki/File:Sauerstoffgehalt-1000mj2.png. The notes below the chart explain ...
2k views

### How often do king tides (perigean spring tides) occur?

Recently, there has been a lot of information about "King Tides" (i.e, perigean spring tides) on the news with a number of groups relating the peak king tide to future normal conditions (2050) under ...
217 views

### Which particles are classified as PM2.5? How exactly is this defined?

Question When discussing "PM2.5", is there any standardized understanding of which particles are or are not included? Is it everything that's 2.5 microns and smaller? Or Everything between 2.5 and 0....
1k views

### If the earth is a globe, what causes temperature differences across lines of latitude?

If the earth is a globe and the sun is 93 million miles away, why is the equator the hottest place on earth? In terms of distances to the sun, the distance to the equator is almost equal to that as ...
376k views

### Why does lightning strike from the ground-up?

The enlightening image below is of a lightning strike slowed down at 10,000 frames per second. It can be seen that the most intense flash produced from the lightening occurs in the direction from ...
4k views

### How do weather models work?

We use different weather models all the time, such as the ECMWF and the GFS. These models are simply amazing to me. How do these models work? I know they have to take in various data points - what ...
11k views

### How do 'greenhouse gases' let heat in, but not let it out?

That honestly doesn't make any sense to me. How could heat pass through a gas one way but not the other? Its not like our upper atmostphere has a bunch of doors that can only open one way. To me, that ...
15k views

### How is the mass of the Earth determined?

According to textbook knowledge, the mass of the Earth is about $6 × 10^{24}\,\mathrm{kg}$. How is this number determined when one cannot just weight the Earth using regular scales?
3k views

### Is earthquake prediction possible?

After the Tohoku and East Coast quakes, I skimmed over several books discussing the validity of earthquake prediction as a discipline, yet found no significant breakthroughs. What should change in our ...
5k views

### How to get cell indices from latitude and longitude in WRF model grids?

I am using Weather Research and Forecasting model WRF and the WRF Preprocessing System WPS and could not get a satisfying answer from wrfhelp. Can anyone guide me in transforming latitude and ...
10k views

### What are the differences between an LES-SGS model and a RANS based turbulence model?

I'm kind of new to the Large Eddy Simulation (LES) modeling world and I wondered what is the difference between an LES subgrid scale model like the Smagorinsky–Lilly model and a one-equation Reynolds-...
2k views

### Why is WRF most often configured at 3:1 nesting ratio?

In WRF application, nested domain has always been used for weather/air quality modeling for the place of interest in a better resolution. The figure below illustrates this: I have noticed that the ...
38k views

### What would be the temperature of earth if there was no atmosphere?

I do know that the atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect),and reducing temperature extremes between ...
6k views

### Is this XKCD comic an accurate timeline of the earth's average temperature?

Apologies for the length of the image, which I found at http://xkcd.com/1732/. I'm mostly interested in the temperature line itself, both the historical data and the forward projections. The reason ...
258 views

### What can we learn by studying lunar atmospheric tides?

Lunar atmospheric tides are likely insignificant for weather, although Guoqing (2005) asserts that The lunar revolution around the earth strongly influences the atmospheric circulation. They don't ...
53k views

### Are clouds a gas, liquid, and/or solid?

Are clouds a solid, liquid, or gas? I have been looking online and they are often described ambiguously as a "mass". For instance, from NASA: A cloud is a mass of water drops or ice crystals ...
2k views

### What sort of climate zones would be present if Earth was tilted like Uranus?

The three main climate zones on Earth are tropics, temperate and polar. Due to Earth's axial tilt, the three zones experience different seasonal patterns: The tropics experience 2 or 4 wet/dry ...
15k views

### Why do crystals, like quartz and diamonds, form in different colors?

Some crystals, like quartz and diamonds, form in a variety of different colors. For example, quartz can be clear, 'foggy', pink, yellow, and even blue. What happens during the crystal's formation to ...
5k views

### What is the origin of the ocean's salt?

We know we cannot live without salt, but an investigation into the origins of ocean's salt leads one to believe that this issue is not fully resolved yet. What geological phenomenon caused the earth ...
15k views

### What was the first rock in the rock cycle?

I am an undergraduate student but I am a tutor at a High School, and one student asked me. Attempting to explain the rock cycle "if one rock turns into the other then which came first" my gut is ...
5k views

### Why don't scientists use fire entry suits to study volcanoes?

It seems like the only personal protective equipment (PPE) that volcanologists use are aluminized suits that don't provide any protection from direct contact with lava, making an unexpected splash ...
2k views

### What causes waves to form the characteristic “breaking” shape as they approach the shoreline?

We all know that as waves approach the shallow shores, the waves begin to form a characteristic shape. The upper portion of these breaking waves appears to curl forward and downwards over the bottom ...
341 views

### How to tell if fog is made out of water droplets or ice crystals?

I understand that clouds can be made out of water droplets and/or ice crystals. And that fog is nothing else than low-lying clouds. However, I've experienced fog in a wide ranges of temperatures. I ...
45k views

### At what humidity does it start to rain?

As far as I understand it is perfectly valid for air to have 100% humidity. At that point, all water can still exist in form of vapor, non-condensed. Does it immediately start to rain if humidity is >...
4k views

### Could the extraction of energy by wind turbines be harmful to the environment?

Wind turbines work by converting some of the energy from wind to electrical energy. Is it possible to have too many turbines, leading to them removing too much energy from the wind? I'm not an ...
3k views

### What were the tallest mountain ranges in Earth's geological past?

There have been numerous episodes of mountain building in Earth's geological history, particularly through the super-continent cycle. Many mountains and mountain ranges have been eroded, as mentioned ...
22k views

### Is the color of the sky the same everywhere on earth?

Is the color of the sky at noon (local time) in, say, NY, Buenos Aires, London, Nairobi, Sydney, New Delhi and Tokyo the same? I choose the specific time of noon to exclude the twilight colors of the ...
2k views

### Does the strength of Earth's magnetic field influence its climate?

The strength and orientation of Earth's magnetic field varies with time. Does this variation of the magnetic field have any influence upon climate? For example, is there any correlation between ice ...
345 views

### What properties must a rocky body possess in order to exhibit plate tectonics?

The Earth exhibits plate tectonics, but the other terrestrial planets do not (though Mars and Venus may have exhibited plate tectonics in the past). What is "special" about Earth that allows it to ...
3k views

### Is there a database of global rainfall time series?

Is there any institute out there collecting time series data of precipitation, and making them accessible online? I need data for a few different locations, but: Low spatial resolution is fine. For ...