Gridded data files for all plots can be found here.
Except for the summer season, Pacific water masses entering the Bering Sea within the mixed layer (at the depth of 7.5 m) are characterized by higher temperatures than the water masses residing in the Bering Sea at the same depth. Major reason for such temperature signal is a relatively high heat content of the Pacific water compared to the one of the Bering Sea mixed layer waters, as well as intense vertical and lateral mixing in Aleutian Passes.
During the summer season, the warmest mixed layer waters are formed locally near-shore in the Bristol Bay, Norton Sound and Gulf of Karaginski. Presence of warm waters in these areas is a consequence of strong stratification observed after melting of sea-ice cover and weak winds which are not able to mix narrow upper warm layer with the waters below. A relatively cold upper layer water is present in summer at the level of 7.5m in several regions of the Bering Sea (e.g. in the central and eastern parts of the Aleutian arc, in the Chirikov Basin and in the Gulf of Anadyr). Due to intense tidal and non-periodical currents in these regions, surface waters are mixed with the underlying cold waters formed in winter and fall.
Large scale temperature distribution the levels of 112.5, 212.5 and 450 m reveals persistent structures present in the Bering Sea in all seasons. The temperature distribution is characterized by temperature maxima in the southern and south-eastern parts of the sea. The origin of these maxima is related to the inflow of the pacific water with its transformation in the straight due to mixing and is supported by cyclonic circulation of the water in the abyssal basin of the Bering Sea. Configuration of the isothermal contours suggests two major regions of pacific water inflow into the Bering Sea - these are the Near Straight and the eastern passes of the Aleutian arc. There are also indications of the propagation of the transformed Pacific water along the north-eastern slope of the deep trench from the eastern passes of the Aleutian arc in the direction of Cape Navarin.
In the layer 550-2250 m spatial variations of temperature are formed by the influence of advection of Pacific water, which is colder than Bering Sea water at the same depth, and by dynamical processes in the region. The temperature distribution in this layer is characterized by similar decrease of water temperature with depth over the basin. The regions with lower temperature are present in the central part of the abyssal basin. These regions are formed by the upwelling of deep waters in the centers of two cyclonic gyres in Aleutian and Kamchatka basins. This effect is more pronounced in the Kamchatka abyssal basin. Anticyclonic eddies generated on the periphery of the abyssal basin along the continental slope due topographic effects result in downwelling and formation of regions with higher water temperature.