Outlined in ink are the relevant coastlines/continental shelves, as you can see there are two inland shelves that are inland/shelf seas. As the major ocean current ends at the southernmost shelf, I'm trying to figure out what the gyres within the inland seas would look like. I understand ocean currents well enough but info on shelf seas, sea of Japan, sea of Okhotsk, North sea etc is few and far between, just looking for some help. Standard earth rotation and size apply, northern hemisphere, with the north pole being just above the top of the page.
Current understanding/assumption is that the two inland seas would retain calmer, saltier and warm currents from what does flow north across the southernmost shelf. Both seas would, in the same way as the Mediterranean, be reliant on the inflow from the open ocean, and would eventually evaporate without it
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$\begingroup$ They are inland seas simply in the sense that on all sides but south, they are almost entirely landlocked. They're not open ocean as the tectonic plates beneath them are continental, not ocean plates, they are simply submerged to due a lack of ice age. The inked outlines are the boundaries of the plates, not necessarily the coast, I'd happily annotate in greater detail, should that be useful. $\endgroup$– Quintessential ConsoomerCommented Mar 2, 2023 at 13:51
1 Answer
If those are inland seas, then the seas would most likely be not tidal, and there wouldn't really be any significant currents as such, but rather slow and erratic drifts driven by wind and by the inflow of water from the ocean. The drifts will be organized into one or two anti-clockwise gyres spanning the inland seas.
(Here is a free online copy of Tarek El-Geziry and Ian Bryden's "The circulation pattern in the Mediterranean Sea", Journal of Operational Oceanography, 3:2, 39-46, DOI: 10.1080/1755876X.2010.11020116, 2010.)
When I say not significant, I mean average speeds of around half a knot, certainly not more than one knot, in other words negligible for purposes of navigation even in the days of oar- and wind-propelled ships.
The one exception is near the straits connecting the inland seas to the ocean, where currents will definitely be significant.
In addition, local geography may make tides significant in certain limited areas, even though the seas in general will be tideless. Even in the Mediterranean there are some few limited areas where tides are quite noticeable.
If those are not inland seas, but just shallower parts of the ocean, like the North Sea, then anything is possible and the picture will be much more complicated than for inland seas; and in additon the seas would be tidal. (Being tidal is important, because the tides will strongly dominate the currents near the coasts in many places, most usually in the most interesting places such as near ports, islands, and straits.)
Here is a picture from Wikimedia, showing the water circulation in the North Sea:
Currents in the North Sea. Map by MagentaGreen, available on Wikimedia under the Creative Commons Attribution-Share Alike 3.0 Unported license.
