Recent Climatic Change Research in the Chukchi and Beaufort Seas Based on Numerical Simulation

Abstract

This study analyses climatic changes in the Chukchi Sea and the Beaufort Sea based on numerical modeling using a regional ice-ocean model. Numerical experiments were carried out for the period 2000–2019. NCEP/NCAR reanalysis data were used to determine the ocean and sea ice surface fluxes. The temperature, salinity, and transport of Pacific waters entering the Arctic Ocean were specified as boundary conditions in the Bering Strait. Three types of boundary values were used for the experiments: a) monthly average climate data averaged over the period 1990–2003; b) monthly average climate data averaged over the period 2003–2015; c) average monthly measurement data since 2016 to 2019. The sensitivity of the model to the variability of the transport and temperature of the incoming Pacific waters was studied, and the effect on the ocean heat content, the volume and sea ice extent was analyzed.Numerical experiments simulate the transport of warm Pacific water across the Chukchi shelf in the north direction and onto the Beaufort Sea shelf, the process of warm water sinking on the continental slope in the autumn-winter period. In recent years, at the points on the boundary of the shelf and deep-water areas, the amplitude of seasonal temperature fluctuations in the surfacelayer increases and the temperature rises significantly at a depth of 100 m.The simulation results demonstrate an increase in the ocean heat content and decrease in the ice volume in the Beaufort and Chukchi Seas, caused by an increase in atmospheric temperature. We also showed that the increase in temperature and transport of the Pacific water, which began after 2003, contributed to an additional increase in the ocean heat content of both seas, a reduction in the ice cover area, and a delay in the ice formation in the Chukchi Sea.