Questions tagged [ocean-currents]

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8
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2answers
887 views

Why is Somalia so dry?

Most deserts are a result of the rainshadow effect, cold currents, the subtropical ridges, or a combination of those. Knowing this, how is the Somali desert caused? It is notable since it has a desert ...
4
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0answers
79 views

how old are the gulf stream and the NAC?

After reading about the NAC (North Atlantic Current) weakening in the news, we got to wondering about its history and that of the gulf stream. Specifically, how and when did they start? Were there ...
9
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1answer
975 views

How authentic was the movie scene in "The day after tomorrow" related to the understanding of the north Atlantic current system?

Today's The Guardian headline was that Climate crisis: Scientists spot warning signs of Gulf Stream collapse. It reminded an old movie called "The Day After Tomorrow", which suggested the ...
3
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1answer
82 views

How fast is the Gulf Stream near shore?

The Gulf Stream is the fastest ocean current in the world with peak velocities near 2m/s, a surprisingly high figure. But I think that the speed is out in the open ocean, and it would be slower near ...
2
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0answers
37 views

What makes Eastern Boundary Currents cold?

As far as I am aware, there are two separate processes that cause Eastern Boundary Currents (EBCs) to have cold Sea Surface Temperatures (SSTs). One is offshore Ekman transport, which leads to coastal ...
4
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2answers
279 views

What is the fastest ocean deep current?

The Gulf Stream is the fastest ocean current in the world with peak velocities near 2m/s. Source: marine.coastal.edu What about deep currents, North Atlantic Deep Water, Antarctic Bottom Water, etc? ...
13
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2answers
232 views

Did the formation of Panama trigger the beginning of Ice Ages?

I have been studying ocean currents and associated energy flows in the eastern Pacific and western Atlantic oceans. I also looked at El Nino cycles. I also noted when the large glacial periods ...
12
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1answer
1k views

Why is ocean surface velocity around 3% of wind velocity?

Many introductory level textbooks suggest that, as a rule of thumb, the velocity of the ocean surface is around 3% the wind velocity at 10 meters above the sea surface. For instance, Ocean ...
12
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1answer
357 views

What is the area with the largest velocity vertical shear in the ocean?

While there are areas with really strong tidal currents in the ocean, these currents tend to be primarily barotropic. My question relates to the largest vertical difference in velocity and it is ...
7
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2answers
585 views

How are chenier ridges and strand plains formed at wave dominated coastlines?

In the attached image, we can see chenier ridges and strand plains. How are they formed and what is the involvement of rip and longshore currents in their formation?
0
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2answers
176 views

Is it possible to get trapped in a circle of water in a rip current?

According to the YouTube video Rip Currents: How to Survive the Deadliest Ocean's Trick, a rip current occurs when there are two circles of water spinning close to shore in opposite directions such ...
4
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1answer
77 views

What is the weather data covering the range of 359 to 360 degree

I downloaded a grib file of oceanography (Mean Wave Period) from ERA-Interim and the longitude values give the value at the points is 0,1, 2, 3....357, 358, 359 If I have geographical coordinates ...
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0answers
47 views

Finding vessel and wave's angle of attack [closed]

I am finding angle between ship's heading and component in wave (wave's angle of attack), not sure if ES is a right place to ask this type of question. Should it be the difference between mean wave ...
1
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1answer
88 views

Where can I find wave height/period, current velocity and wind speed/direction data at the Qiangzhou strait in China?

I'm looking for time series of wave height/ period, velocity currents and wind speed/direction specifically for the Qiangzhou strait in China. Global data sets could also work.
3
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0answers
48 views

Why an inertial gyro has a frequency and a geostrophic gyro does not?

Inertial flow is given by the balance between Coriolis and centrifugal forces. A geostrophic flow is given by a balance between Coriolis and the gradients of pressure. The frequency of the inertial ...
5
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0answers
231 views

Why do Mediterranean main currents surrounding landmasses turn counter-clockwise?

At North Hemisphere, main superficial currents turn clock-wise, because of Coriolis Effect. I would expect on Mediterranean Sea to have currents turning in the same sense, but, surrounding landmasses,...
8
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2answers
119 views

What goes into a tide power prediction for every fifteen minutes over the next twenty five years?

I was watching a segment about tidal power generation on a PBS NewsHour broadcast. I've set the time code at about 11:45 to capture a little background. This bit ...
3
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1answer
88 views

Velocity gradient of surface ocean current in dephts

How much speed of surface currents decrease in ocean depth? Approximately? I am wondering if there is any significant gradient within the top 30m ocean layer? Can this be theoretically calculated?
9
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1answer
105 views

How is the distribution of Argo floats managed over the Earth's oceans?

The BBC News article Climate change: Oceans 'soaking up more heat than estimated' mentions Argo floats as one technology to measure the temperature of the oceans, and links to argo.ucsd.edu where ...
12
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1answer
920 views

What is the (average) velocity of ocean currents?

Does anybody know where to find statistical (average, standard deviation) data on velocities of ocean currents, such as Equatorial countercurrent North of Madagascar Agulhas current East Australia ...
13
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2answers
1k views

Forecasting oceanic rogue waves

A rogue wave is, according to NOAA, "a large, unexpected and dangerous" oceanic wave. These are also known as 'killer' or 'freak' waves and have been a part of folklore of the past and observation of ...
4
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0answers
82 views

Is there a correlation between the underwater geological activity and topology of the mid Atlantic ridge/ South American plate and the Gulf Stream?

I just had a little eureka moment! I was looking again at this mid atlantic ridge along the western edge of the Eurasian plate. https://en.wikipedia.org/wiki/Lists_of_volcanoes How it and the way it ...
5
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1answer
310 views

Why does wind blowing against a strong current create way bigger waves?

It's a well known fact that wind will cause very big waves if blowing against a strong current, for example in the gulf stream off the US coast, or in the bay of San Francisco with a very strong (5 ...
5
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1answer
2k views

Why don't Antarctic waters have more upwellings, when Arctic waters are so rich in upwellings?

Formation of ice and hence more dense saltwater sinking happens in both polar regions, creating downwellings. Meanwhile, only a few spots in Antarctica have upwellings I refer to this image: https://...
4
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0answers
106 views

Stream function on a periodic domain?

Part 1 In this paper the authors calculate the barotropic stream function from an output of a numerical model as: $$\psi(x,y)=\int_0^y\int_{-H}^0u(x,y',z)~dz~dy'$$ over a global domain and this is ...
4
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1answer
349 views

If a prevailing wind traveled due east in the Northern Hemisphere, would the Coriolis Effect act on the water?

I am in a Marine Environmental Science II class, and we are discussing the Ekman Spiral. As I understand, the Coriolis Effect does not occur when whatever is observed does not change latitude. So, if ...
7
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2answers
297 views

What mechanism is used to measure ocean currents from cables?

The volume transport of the Florida Current (one of the parts of the Gulf Stream) is measured using an underwater cable. What are the processes that allow for these measurements? How can we obtain ...
5
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1answer
526 views

Guinea Current existence in the Atlantic

Why does the Guinea Current exist at all? There are no similar currents in the Pacific or Indian Oceans and the Guinea Current also disappear during northern summers. Why?
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3answers
209 views

Thermohaline current in North Atlantic

The thermohaline current in the North Atlantic ocean sinks because it gets cooled, or it gets cooled because of sinking?
5
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1answer
561 views

Depth of the wind-induced currents and the shoreline

In the open sea the speed of the current in the developed sea can be estimated as 3% the wind velocity at 10 meters. Why is ocean surface velocity around 3% of wind velocity? Is there a similar ...
3
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2answers
157 views

Land's effect on winds and currents?

If we did a thought experiment and imagined the Earth to be covered in a global ocean (ie. no land to slow winds or direct ocean currents) would winds and waves be perpetually enormous or would they ...
4
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1answer
533 views

Difference in surface temperature between the Northwest Atlantic and Northeast Atlantic

Why is the surface waters in the Northwest Atlantic Ocean colder than the surface waters of the Northeast Atlantic Ocean?
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0answers
260 views

Is there a formula to calculate shoreline length or water position from ocean?

Assuming in the past the water of the oceans were lower does it also mean that the water was not where it is right now?
 If yes, then how do we calculate approximately where the water would have been ...
3
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1answer
694 views

How to calculate the kinetic energy spectra from ocean current timeseries?

How does one practically compute the kinetic energy spectra from a timeseries of u- and v- Cartesian components of ocean current velocity ($m s^{-1}$) obtained from an Acoustic Doppler Current ...
2
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2answers
137 views

If a ship on its way to Germany from Norway sank, where will the survivors likely end up?

a) what are the chances, taking into account influencing factors like ocean currents, that these survivors will end up on English shores? b) what are the chances, again taking into account all ...
9
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0answers
106 views

How much does the Meridional Overturning Circulation strengthen the Gulf Stream?

While the Gulf Stream is a western boundary current (WBC), one professor told me that the Gulf Stream is stronger than it should be just by using theoretical calculations of WBC. How much is the heat+...
3
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1answer
270 views

Why is Thermohaline Circulation (THC) pivotal to life on Earth?

Thermohaline circulation (THC) is an instance in nature in which oceanic fluctuation of amassity, temperature and sodium matter is observed on a global scale. It is compared to and sometimes called ...
2
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0answers
520 views

Do U & V vectors differ depending on GRIB layers (wind vs current)?

Essentially I would like to know how current direction "DIR C" and wind direction "WDIR" for gribs is computed. I'm trying to compute some angles from u and v vectors in grib files. My understanding ...
15
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4answers
8k views

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 ...
25
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1answer
42k views

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 ...
2
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1answer
217 views

North Bay of Bengal warm pool anomaly

I am looking for an explanation for this warm pool of water in the North and North East Bay of Bengal - North Bay Warm Water Anomaly. Currently the path of the sun is towards the southern hemisphere ...
4
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2answers
1k views

Why is Vladivostock so cold, while Dalian is so warm?

Over at SE History we're pondering the relation of temperature to Russian motives in establishing its Port Arthur colony in the late 1800's. Wikipedia says that Vladivostok is cold due to the ...
2
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1answer
100 views

Making Sense of Coldwater Ocean Currents

The basic understanding of ocean currents is that warm currents carry moisture whereas cold currents carry nutrients. This is why some scientists believe in the connection between the Arctic ice caps ...
5
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1answer
581 views

Is the gulf stream both a wind-driven current and part of thermohaline circulation?

Currents are formed in 3 major ways: Tidal Currents Wind-driven Currents Thermohaline circulation I've seen the gulf stream mentioned as both a wind-driven surface current and being part of the ...
7
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2answers
5k views

Thermohaline: Why is cold and dense seawater salty when warm water holds more dissolved salts?

I read that thermohaline circulation is caused by cold and saline water sinking, while warm and less dense water rises. link I understand that saline water is more dense, as there is a higher mass ...
6
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1answer
61 views

Can up-welling water at oceanic fronts be physically felt?

If you were swimming/floating within a body of water experiencing upwelling due to sea-surface thermal fronts, would you be able to physically feel the water that is being up-welled or is it on a ...
6
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1answer
821 views

ocean current frequency

In this paper by Muller and Garrett it is stated: It is a standard expectation that currents in the ocean interior with frequencies much less than the Coriolis frequency will lead to an Ekman ...
8
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1answer
933 views

What is the relationship between Ekman transport and Ekman pumping?

Ekman transport is the integrated horizontal flow in the boundary layer resulting from the balance between frictional forces (at the surface or bottom) and Coriolis. Meanwhile, Ekman pumping is a ...
14
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1answer
1k views

What is the force imposed by underwater currents?

I would like to calculate the force of an underwater current on a meter by meter plate (or any other unit that you may use to represent it) that is standing in front of the current. How do I calculate ...
16
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2answers
2k views

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 ...