Analysis of Thermal Conditions in the Northwest Pacific Ocean from Satellite Data

Monthly average values of sea surface temperature from January 1998 to August 2020 are analyzed for the region covering the water area of the Far East seas and the northwestern part of the Pacific Ocean. The time function of the first mode, which describes more than 95% of the variance of a parameter under study, has been shown to have significant positive deviations from the average long-term values in January–April 2020 in the southern part of the study area, which covers the traditional feeding grounds of pink salmon. It may have been these abnormally high temperatures that affected the fish survival conditions and obstructed the spawning passage to the Russian Far East shores in the summer of 2020. In spring (May–June), the anomalies in the southern part of the study area became less expressed, but significant positive deviations from the norm appeared in its northern part and near the eastern (including the Karaginsky Bay) and western coasts of Kamchatka. Only very weak uptrends were revealed in time functions of the principal modes, indicating that there are no significant global warming trends in the region. Their envelopes with respect to lower values involve a clear manifestation of an 11-year cycle that is in antiphase with solar activity indices. No regular (for example, cyclical) components are found in variations of summer maxima in the time function of the first mode. In the oscillations of maxima of the time function of the second mode, the main contribution is made by the cyclic component with a period of 22 years.