45 votes

Why doesn't the 71% water of the earth dry or evaporate?

There are two ways this problem needs to be looked at. The first is more astronomy than Earth science. The Earth as an entire system is largely contained. Its gravity and magnetic field retains ...
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  • 5,707
43 votes
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How does global-warming-triggered ice melting cause global sea levels to rise?

Arctic ice, around the north pole floats on top of water. When it melts it does not add to sea level rises and likewise for other ice on water, as illustrated in this video and this video. Ice on land ...
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  • 20.7k
41 votes

Why are the Great Lakes not considered a sea?

"Sea" versus "lake" versus "just part of the ocean" is a bit fuzzy, but there are two things that are universal about seas: They are saline. They are either endorheic or have a sea-level (tidally-...
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  • 1,180
38 votes

Why does the salt in the oceans not sink to the bottom?

When dissolved in water, salt breaks up into sodium and chlorine ions, which combine with water molecules so they cannot easily sink. However, there is a tendency for streams of fresh water to float ...
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35 votes
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Why is relative sea-level falling in Hudson Bay?

The area is experiencing post-glacial isostatic rebound. Much of Canada was covered in an extensive ice sheet in the last glacial period (the 'Ice Age'), from about 110 ka until 12 ka. The ice in the ...
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  • 10.7k
34 votes
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Are there any uncharted waters left on earth?

There are many "uncharted waters". Nautical charts have information about water depths, dangers to navigation, aids to navigation, anchorages, and other features. You can see here what might be ...
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  • 12.7k
33 votes

While desalinating ocean water, would it be bad if we didn't pump the brine back into the ocean?

What does it take to reduce the salinity? The salinity of sea water is around 35 g/kg. There are around 1,350,000,000 km³ of water, so roughly 1.3x1021 kg of seawater (1 kg/l, which is a bit off for ...
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  • 431
32 votes
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Why is the sea salinity high in the Mediterannean and Red Sea and low in Indonesia and Malaysia?

It has nothing (or very, very little) to do with desalinization plants. It has to do with the balance between Evaporation minus Precipitation (E-P), rivers, and advection. The link to E-P is the main ...
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  • 14.7k
30 votes

How and why did the oceans form on Earth but not on other planets?

Your assumption that there is not a lot of water elsewhere in the solar system is incorrect. According the this article on NASA's website; Missions in recent years have overturned our view of a dry ...
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29 votes

Why does the salt in the oceans not sink to the bottom?

Why does the salt in the oceans not sink to the bottom? Because there isn't any "salt", per se, in the ocean. Salt, as the compound sodium chloride (NaCl) does not exist as a solid in the ocean. It ...
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  • 22.2k
27 votes
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Where do rivers like the Rio de la Plata end and the ocean begin?

In the case of Río de la Plata, part of it is history and politics, and part of it is oceanography. Most of Argentina and Uruguay considers Río de la Plata as a river (thus, the name, río) and as ...
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  • 14.7k
26 votes
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How can the world's sea level rise and fall simultaneously?

There are lots of controls on sea level, not just the volume of water in the world ocean. These controls operate on different time and spatial scales, and interact in nonlinear ways. As a result, both ...
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  • 10.7k
26 votes
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Why doesn't sea level show seasonality?

Sea level has a strong seasonal signal. The annual variability is less than the daily changes associated with tidal forcing in most locations, but still can be on the order of 5-10 cm (maximum values ...
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  • 14.7k
25 votes
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How and why did the oceans form on Earth but not on other planets?

The water was already present when the Earth assembled itself out of the accretionary disk. Continued outgassing of volcanoes transferred the water into the atmosphere which was saturated with water. ...
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  • 3,876
25 votes

Why doesn't the 71% water of the earth dry or evaporate?

Why doesn't 71% water of the earth dry or evaporate? The simple answer: Because it rains. The not so simple answer: By some estimates, the Earth has already lost about a quarter of its water, and it ...
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  • 20.2k
24 votes
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Are there secondary causes of sea level change?

Yes, there are lots of other factors. Factors affecting sea levels are no different from other natural processes: there is a large number of coupled, non-linear effects, operating on every time ...
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  • 10.7k
23 votes
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How is ocean salinity measured from space?

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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  • 11.1k
23 votes
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Why are there waves in seas towards shore - even in night?

Ocean waves (and also in mediterranean type seas and larger lakes, but on a smaller scale) are generated by two processes: locally generated waves ("wind waves"), which follow the direction of the ...
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22 votes
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Is there a geological explanation for the recent Mammoth tusk discovery 185 miles off the California coast?

The mammoth probably died on land. Its remains got picked up by a glacier. The glacier carried the tusk down to the sea. Eventually, the ice containing the tusk broke off as an iceberg. The iceberg ...
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  • 3,038
21 votes
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Would hurricanes on an ocean planet continue indefinitely?

No. As it is, many hurricanes never make landfall. In an oceanic world I could see three fates happening: Hurricanes that dissipate due to dynamical features or climatological features. By dynamical ...
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19 votes

What tools allow a quick comparison of NetCDF output from ocean models?

For very quick visual comparison I would use Cube Browser or ncview together with a command line tool like the Climate Data Operators. For quick production of nice looking graphics (and animations) ...
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  • 1,662
19 votes

While desalinating ocean water, would it be bad if we didn't pump the brine back into the ocean?

The residue dry powder you refer to is salt. Salt is toxic to most plants. The United Nations claims the world is already losing 2000 hectares per day of farm land to salt-induced degradation. This is ...
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  • 20.7k
18 votes

Great Pacific Garbage Patch Equilibrium Points

Theoretically, I agree that there should be one instable equilibrium point between the two stable equilibrium points when we have a 2D current field. However, there are some additional components of ...
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18 votes
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Great Pacific Garbage Patch Equilibrium Points

Yes, you're right, there should be (at least one) saddle point in the middle of the loop. And indeed, if you search for illustrations of Pacific ocean circulation, you can see the saddle point in ...
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18 votes

How much does sea level rise due to sediment deposition?

In a 1983 Journal of Geology paper by Milliman and Meade, "World-Wide Delivery of River Sediment to the Oceans" (link) it is estimated that the world's rivers carry about $13.5\times 10^9$ tonnes of ...
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  • 1,374
17 votes
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What tools allow a quick comparison of NetCDF output from ocean models?

The writers of netCDF, UNIDATA, maintain a pretty extensive list of visualisation software on the netCDF website. It even mentions an Excel add-in, for the masochistic, presumably. Over the years, I'...
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  • 3,153
15 votes

How is ocean heat content measured?

The easiest way this is measured is via Argo floats. They're probes which periodically dive into the sea, and measure the ocean heat content. This is done by calculating the formula. According to the ...
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  • 1,940
15 votes

What was the ocean circulation like during the time of Pangaea?

Here is an estimate from Beauchamp and Baud (2002), for parts of the ocean around Pangea, for the latter parts of it's existence (~300-250mya). It is based on various previous papers that looked at ...
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  • 5,327
15 votes
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What influences tide-height the most? Can I guess the height by looking on a globe?

I don't know about the size of land masses, but their distribution and the shape of ocean basins definitely play a big role. When considering the ideal case of an all-ocean globe, i.e. one with no ...
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15 votes
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Are there seamounts as close as 100 m to the water surface and not inside any Exclusive Economic Zone?

Yes, there are many. According to the seafloor topographic data of ETOPO (1 arc second resolution), and the Exclusive Economic Zones (EEZ) database of marineregions.org. There are at least 157 ...
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