Plan B: the Diomede Threshold
Partially closing off the Bering Strait by building a threshold, on the same location as the dam of plan A, limiting water inflow to a certain depth.
Effects
1. Temperature
Similarly to plan A a decrease of temperature in the Chuckchi can be expected, although the effect is likely to be far less pronounced. Partially sealing off the Bering Strait will allow for some heath exchange between the Pacific and the Arctic to remain. Also noteworthy: a close off of for example 80 percent is unlikely to leave just 20 percent of the Pacific inflow remaining as, most likely, it will lead to an increase in flow velocity.
2. Dynamics
As for temperature plan B seems unlikely to have big effects on dynamics, as there will be no dam above the water line to lessen wind fetch. Since a small decrease of the Pacific inflow remains to be expected, on a larger scale plan B could, theoretically, contribute to a decrease in sea ice outflow towards the Atlantic.
3. Salinity
The big reason to opt for plan B is off course that it will allow for freshwater inflow from the Yukon to remain. What’s more, at a cleverly adjusted altitude plan B can actually help decrease salinity in the Chuckchi, making use of the salinity gradient of the water that increases with depth, as saltier water is heavier.
Under the present conditions in the Bering Strait the Yukon freshwater indeed seems to flow on top of the saltier Pacific sea water. It seems plausible therefore that a threshold in the Bering Strait could decrease salinity of the inflowing water, without decreasing discharge too much, to the extent that a decrease of salinity in the Chuckchi can also be expected, favouring sea ice conditions.
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