Questions tagged [oceanography]

Oceanography is the branch of Earth science that studies the ocean. It is also known as oceanology.

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39
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4answers
7k views

Are there any uncharted waters left on earth?

While reading about the ghost ship Jiang Seng I noticed that Wikipedia claimed it was drifting in uncharted waters in the Gulf of Carpentaria. I tried to find a primary source referencing uncharted ...
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Similarities between grand circulation solvers and mantle convection solvers

My impression is that both ocean grand circulation models (e.g. MITgcm), and Mantle Convection models (e.g. CitcomS), both use Navier-Stoke's as the governing equation. What are the other major ...
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How and why did the oceans form on Earth but not on other planets?

Earth is the only planet in our solar system that has copious amounts of water on it. Where did this water come from and why is there so much water on Earth compared to every other planet in the ...
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Why is relative sea-level falling in Hudson Bay?

Why is the sea level in Hudson Bay decreasing so much? Hudson Bay is pretty far up north, much closer to glaciers. Would it make sense for it to recede at this level with sources of fresh water ...
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Why does El Niño only exist in the Pacific Ocean and not the Atlantic/Indian Oceans?

El Niño is associated with the weakening of the ‘normal’ pressure/temperature gradients between the western and eastern Pacific Oceans. My question is this: why does it only exist in the Pacific ...
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1answer
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What is responsible for the underwater waterfall illusion of Mauritius Island?

From an aerial view just off the island of Mauritius, there is what appears be an underwater waterfall. The picture below illustrates this visual phenomenon: The image can also be seen from the ...
23
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8answers
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Why does the salt in the oceans not sink to the bottom?

This is something that just occurred to me. If heavier elements sink, then how can the entire ocean be salty? Shouldn't the 'salt', because of its density, all sink to the bottom of the ocean? In ...
22
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4answers
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What causes bottom water to rise?

The water close to the deep ocean floor is called bottom water. It may be located in deep valleys or trenches. I understand that water flowing to the Arctic will sink there, because it's saltier and ...
22
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1answer
2k views

How can the world's sea level rise and fall simultaneously?

I have just been reading this article on Gizmodo (known for its hard science I know), that talks about sea level rising by up to 3 feet(!). In the article and video, created from information from ...
22
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1answer
521 views

How is ocean salinity measured from space?

Since 2009, two satellites (SMOS from ESA and Aquarius from NASA) are providing global salinity measurements. While ocean temperature is easily derived from infrared radiation for instance, what ...
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Are there pockets of liquid carbon dioxide in Earth's oceans?

The carbon dioxide phase diagram shows that at high pressure and normal temperature CO2 becomes liquid. Since it is heavier than water, I wonder if there are lakes of liquid CO2 at the bottom of the ...
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What tools allow a quick comparison of NetCDF output from ocean models?

I am writing my own MATLAB scripts to do most of the visualization and data analysis of model results. I wonder if there is a quicker way for visual comparison of simulation results gained from ...
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How can I improve the numerical stability of a coastal hydrodynamic model?

I am working with a coastal hydrodynamic model in the MIKE3 modelling package. MIKE3 uses the finite volume method to solve the shallow water equations with explicit timestepping, over a triangular ...
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3answers
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Why are the Great Lakes not considered a sea?

From me looking at maps, excluding the Caspian sea and the Great Lakes, I see these in common for seas and lakes: Seas Most are saltwater Connected to the rest of the ocean via either an isthmus, ...
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2answers
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 ...
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Current consensus on the Messinian Salinity Crisis

In 1973, Hsü et al. explained the findings of a large evaporite deposit during the Messinian (Latest Miocene stage, ca. 6Ma) in the Mediterranean by a basin-wide desiccation event. It has been ...
19
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1answer
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What was the ocean circulation like during the time of Pangaea?

So Enderton and Marshall (2009) wrote an interesting paper on the ocean circulation of various aquaplanets covered with certain terrain: e.g. an aquaplanet with a small ridge of land that ranged from ...
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1answer
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What fraction of dry land is below sea level?

Someone just asked me if it would be practical to counter the rise of sea level by pumping water into storage on land. It struck me that if there is enough land below sea level, this would require ...
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6answers
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Why doesn't the 71% water of the earth dry or evaporate?

Perhaps a simple question, we know 71% of the earth's surface contains water as oceans. If Earth's age is 4.543 billion years, then I guess it should be decreased with drying or should have been dried ...
18
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2answers
739 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 ...
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2answers
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Historically, how has the fraction of Earth covered by water changed?

Today, 70.8% of the Earth is covered in water (± a few tenths of a percent depending on how you account for lakes).1 How has this figure changed over the history of the Earth, and why? Of course, if ...
18
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1answer
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How long does it take for the ocean conveyor to circulate?

What is the period of the thermohaline circulation in the ocean? Obviously, individual particles may take longer or shorter, but what is the average for a small water parcel to do a full loop and end ...
18
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1answer
149 views

Paleogene transantarctic seaway

Lawver & Gahagan (1998; 2003) hypothesized, based on sea level records and the isostatically adjusted bedrock surface of Antarctica, the existence of a Trans-Antarctic Seaway linking the Ross Sea ...
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1answer
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What is the importance of mixing caused by outgassing in the ocean?

I have been asked the following question for which I have no clear answer: What is the relative importance on mixing of the vertical flow of gases (e.g., Oxygen produced by photosynthesis, CO2 ...
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3answers
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Why deep ocean didn't freeze during snowball Earth?

I know that at least twice in its history Earth was totally frozen. I also know that the last time it happened there were already life on Earth, and it survived. In deep water, under the ice, which ...
17
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1answer
594 views

To what extent is hydroelectric power really renewable?

One of the more widespread "renewable" ways of generating power is by harnessing hydropower, i.e. by exploiting the movement of falling or flowing water. Some of the most commonly seen implementations ...
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1answer
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What influences tide-height the most? Can I guess the height by looking on a globe?

I hope that the question title is resonably clear: What are the most significant factors which influence the tide height? I'm aware of the following couple of them: Sun-Earth-Moon relative position (...
17
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1answer
162 views

What is the appropriate vertical datum to use globally?

When studying sea level changes, it is normal to analyze water level with respect to a common vertical datum. The most used datum is Mean Sea Level (MSL), which NOAA defines as "The arithmetic mean of ...
16
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2answers
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Great Pacific Garbage Patch Equilibrium Points

I was watching the science channel yesterday and the program mentioned the Great Pacific Garbage rim. I was struck by the illustration (and pretty much every subsequent animation/picture I've seen now ...
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2answers
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Where do rivers like the Rio de la Plata end and the ocean begin?

We just had visitors (in Monterey, California) from Montevideo, Uruguay. Not being very familiar with Uruguay, after having taken them to Big Sur, I asked them how far they lived from the ocean. ...
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2answers
761 views

How does remote sensing of ocean currents work?

I am aware that techniques exist for measuring surface currents using HF radar, either from land-based installations or from space. How do these work? I have assumed in the past that it's some sort ...
16
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1answer
296 views

Potential explanations of Red Sea crossing

I am looking for a believable explanation of the Red Sea Crossing in the Bible. This would involve either strong winds(which is mentioned in the Bible) or plate tectonics which could cause land to ...
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3answers
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What is the percentage of the global water cycle (evaporation, precipitation) that occurs over the ocean?

Most of the water cycle studies focus on the processes and changes occurring over land with little emphasis on the ocean. Meanwhile, the ocean covers almost 3/4 of the surface of Earth. How much of ...
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1answer
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Impact craters under water

What would be the resulting impact crater of a meteorite hitting bodies of water on Earth? Let's take for example the impactor that resulted in Meteor Crater, Arizona. What would the impact look like ...
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4answers
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Is there a way to find the direction to land in the middle of an ocean?

Can I find the direction to land when I am in the middle of the ocean and can not see any land? This is a theoretical question. Any method that doesn't use over-technical methods such as smartphones ...
15
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1answer
341 views

What is the predictability of El Niño/La Niña?

What is the maximum period of time into the future that an El Niño event can be forecasted with reasonable accuracy and what are the limitations in predicting the time limit?
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2answers
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Lanes of flat ocean surface in coastal waters

When the ocean is still, i.e. there aren't waves that disturb the surface, you often see "lanes" of water that seem flat as opposed to areas where the wind causes ripples. What causes this?
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Why does the El Niño Stop?

The reason for the initiation of the El Niño is unknown, but what is well known is how it progresses once initiated. The West Pacific warm pool begins to drift East, and the strength of the trade ...
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2answers
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At the ocean surface, why do large amplitude waves travel faster than small amplitude waves?

I understand the mathematics behind it but I am looking for an intuitive description.