VOLUMETRIC CHARACTERISTICS OF PACIFIC WATERS IN THE ARCTIC OCEAN

Volumetric characteristics and renewal time of the Pacific waters (PW) in the Arctic Ocean were calculated based on the data of oceanographic expeditions during the 2007-2008 International Polar Year (617 stations). Isopycnal surfaces of their upper and lower boundaries (25,5 and 27,5 kg/m3, respectively), the thickness between these limits and the equivalent thickness (i. e. the specific thickness of untransformed “pure” water mass) have been determined, as well as the boundaries where the highest concentrations of silicates in the selected density interval disappears. The Pacific waters extend to the north up to the North Pole region (thickness up to 40-50 m), in the west they can be traced up to the northern part of the Laptev Sea (thickness 20-30 m), in the east they are preserved in a minimally transformed form (thickness of more than 100 m) up to the Canadian Arctic Archipelago. The characteristic depths are between 50 and 150 m. The thickest PW exceeding 150 m were found within the Beaufort Gyre. The total volume of “pure” (untransformed) Pacific waters in the Arctic Ocean was estimated at (197 ± 19) · 103 km3 or about 1,1% of the overall volume of the Arctic Ocean. If their mixing with the surrounding waters between selected isopycnic surfaces is taken into account, the volume of Pacific waters is (313 ± 16) · 103 km3, or about 1,7% of the volume of the Arctic Ocean. Taking into account the total inflow of the PW through the Bering Strait, their renewal time in the Arctic basin is estimated to be about 5-6 years.