Questions tagged [ocean-currents]

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5 votes
1 answer
291 views

Does the California cyclone change the California current?

I opened windy.com for the California area and I found that the California current is displayed in the opposite way - from south to north. Is it affected by the recent cyclone or am I misunderstanding ...
5 votes
1 answer
63 views

Indonesian Throughflow and currents map

According to Wikipedia, Indonesian Throughflow passes Lombok Strait from north to south bringing water mass from the Pacific Ocean to the Indian Ocean. But when I the checked currents map on windy....
1 vote
1 answer
28 views

How to construct the tide signal from harmonic constituents?

I am trying to reconstruct the astronomical tide time series from harmonic constituents (calculated from T_Tide).I am using the equation that all knows H(t) = Amplitude * cos ( t * harmonicSpeed + ...
28 votes
1 answer
43k 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 ...
1 vote
1 answer
66 views

Gulf stream depth and Ekman's theory

The Gulf Stream is said to be Largely driven by wind stress, and Up to 1000 m deep. At the same time, I am reading that the effect of the wind usually does not reach deeper than 100 m in Ekman ...
2 votes
0 answers
46 views

(Why) is the thermohaline circulation not affected by the coriolis effect?

Why doesn't (e.g.) the equatorward North Atlantic Deep Water bend more to the west? Is it maybe because the water tends to move relatively slowly and the magnitude of the Coriolis effect depends on ...
3 votes
1 answer
99 views

Are there any types of winds or waves that are produced just by Earth's rotation?

Are there any types of wind or waves caused and produced only and exclusively by Earth's rotation? Not influenced by Earth rotation, but produced solely by it? In the case of waves, are Rossby waves 1 ...
4 votes
0 answers
27 views

Why do the isotherms bulge north of the Bering Strait in winter, and bulge south of the Bering Strait in summer?

My grade-7 geography textbook contains these world average temperatures for January and July. Average air temperatures in January (winter in the northern hemisphere) Average air temperatures in July ...
2 votes
0 answers
27 views

Velocity boundary conditions from water depth time series

Currently, I am setting up a hydrodynamic model for a coastal zone. For this purpose I need to impose the velocity and water level at the open boundary. Tidal models (e.g. TPXO) can give both velocity ...
2 votes
0 answers
30 views

What is the relationship between Ekman transport and volume transport?

Ekman transport components are in the zonal and meridional direction. Along the coast of California, which is an eastern boundary coast, say there is wind flowing down the coast in the meridional ...
0 votes
1 answer
53 views

How far do substances travel when thrown into the ocean?

If I walk up to a pier and throw kool aid into the ocean, where will those kool aid particles end up on a long enough time scale? Is it arbitrary? Will they travel the entire ocean at one point?
2 votes
2 answers
244 views

How large were Mars' ocean tides and to what extent could they keep the oceans mixing and tend to keep salinity uniform? Has this been modeled?

This answer to Salinity of Martian water 3.5 Billion years ago in Astronomy says that most estimates of Mars' ocean's salinity are pretty high; The article "Water Activity and the Challenge for ...
8 votes
2 answers
2k 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 ...
5 votes
0 answers
330 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 votes
1 answer
1k 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 votes
1 answer
100 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 ...
3 votes
0 answers
53 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 votes
2 answers
2k 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 votes
2 answers
282 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 votes
1 answer
2k 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 votes
1 answer
387 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 votes
2 answers
753 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?
2 votes
2 answers
248 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 votes
1 answer
80 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 ...
1 vote
0 answers
51 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 vote
1 answer
105 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.
4 votes
0 answers
55 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 ...
6 votes
0 answers
327 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 votes
2 answers
126 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 votes
1 answer
245 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 votes
1 answer
110 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 votes
1 answer
1k 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 votes
2 answers
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 ...
5 votes
0 answers
84 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 votes
1 answer
431 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 votes
1 answer
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://...
5 votes
0 answers
136 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 votes
1 answer
402 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 votes
2 answers
321 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 votes
1 answer
530 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?
1 vote
3 answers
212 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 votes
1 answer
623 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 votes
2 answers
164 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 votes
1 answer
601 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?
1 vote
0 answers
393 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 votes
1 answer
828 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 votes
2 answers
155 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 ...
10 votes
0 answers
114 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 votes
1 answer
278 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 ...
3 votes
0 answers
595 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 ...