Interannual variability of ice volume in the sea of Okhotsk during the maximum development of ice extent for 2000–2020

Abstract

Based on the interpretation and analysis of data obtained from passive and active microwave spectroradiometers installed on artificial Earth satellites, the boundaries of the ice extent zones in the Sea of Okhotsk with different age characteristics for the period from 2000 to 2020 have been defined and discretized into monthly components. Weighted average ice thickness in the selected zones has been calculated for three dominant age groups of ice according to World Meteorological Agency Nomenclature without adjustment for ice deformation. Analysis of the estimated characteristics has allowed us to conclude that in the XXI century there was a decrease in the volume of ice in the Sea of Okhotsk by 162 cub.km (or 51.9%). Ice volume decreased at average speed of 7.7 cub.km (or 24.7%) per decade, while ice extent decreased by 11.2% per decade (or 23.6%), and weighted average ice thickness – by 14.1% per decade (or 29.6%). For the 2000 to 2020 research period, changes in the volume of ice have been due to decrease in its thickness by ~ 56% and ice cover by ~ 44%. It has been established that the nature of the development of the ice regime parameters within the boundaries of the regions of the first hierarchical level varies significantly.