Анализ вариаций ледовитости Охотского моря на основе авиационных и спутниковых наблюдений

Abstract

The paper presents the results of a study of the Sea of Okhotsk ice cover variability for the period 1961–2020. Based on aviation and satellite observations for the first time, the calculations of anomalies in the Sea of Okhotsk ice cover were performed for two nonintersecting standard climate normals of 1961–1990 and 1991–2020. Statistical analysis made it possible to quantify the changes that occurred against the background of modern climate warming. The general downward trend in the ice cover of the Sea of Okhotsk for the period from 1961 to 2020 is 3 % per 10 years, and the range of fluctuations reaches about 40 %. It was shown that for the standard climate normal 1991–2020 was characterized by a decrease in the average ice cover for the season by 10 %. The date of the onset of the seasonal maximum of the sea ice coverage in the context of the global trend of increasing air temperature shifted one decade earlier than the date that was determined for the period 1961–1990. (March 5 and 15, respectively). In the phase of intense ice formation, there is a delay in the development of ice processes by 10 days, and in the phase of destruction, it is ahead by 15 days. It is shown that changes in the intraseasonal course of the ice cover in the Sea of Okhotsk that have occurred in the last 30 years are most significantly manifested in the phase of ice cover destruction. In the long-term course of ice coverage anomalies calculated relative to the standard climatic norm of 1991–2020, starting from 2004, there has been a sharp increase in the frequency of negative anomalies (up to 81 %), which indicates a unidirectional development of the process of reducing the ice cover in the Sea of Okhotsk.