FORMATION AND SINK OF DENSE SHELF WATERS IN THE AREA OF THE CONTINENTAL SLOPE (CASCADING) OF THE NANSEN BASIN IN THE LAPTEV SEA

摘要

Large-scale advection of surface waters, freshened by the river runoff, from the Kara Sea or saltier waters from the Franz Josef Land and Spitsbergen regions during the preceding summer determine the depth of development of winter sub-ice (salinity) gravity convection on the shelf of Severnaya Zemlya in the Laptev Sea, the efficiency of formation of dense shelf waters, and the intensity of sink of shelf waters along the continental slope (cascading) of the Nansen Basin. With respect to hydrometeorological and topographic features, the shelf and the continental slope of Severnaya Zemlya are subdivided into the northern part, where the slope cascading is more intense, and the southern part, where it is less intense. On the shelf and the shelf edge in the upper 200-m layer, salinity is responsible for the formation of the bottom gravity current of shelf waters. Below, in the upper part of the continental slope (200-800 m), the baroclinic front of shelf waters has a distinct thermocline character and the temperature is responsible for the slope cascading, although shelf waters are less saline than neighboring Atlantic waters. Thermoclinicity in the bottom horizons against the background of a smooth (horizontal) density field at the shelf edge or in the upper part of the continental slope is another indicator of the cascading of shelf waters in the Severnaya Zemlya area.