Analyzing Causes for the Environmental Disaster in Kamchatka in Autumn 2020 Due to a Red Tide Based on Satellite Data

This paper presents the results of integrated space studies of the environmental emergency near the Kamchatka Peninsula which caused the mass death of hydrobionts in autumn 2020. This research is based on the processing and analysis of long-term series of optical multispectral and radar satellite images of the sea surface (similar to 22 000 scenes), including data on the sea surface temperature (from 1981 to 2020) and the concentration of chlorophyll a (from 2000 to 2020). It is revealed that there were strong positive temperature anomalies in the study area in July-September 2020 (the deviations from the climatic norm reached 6 degrees C), which led to a significant change in the biogenic regime and an abnormal increase in the concentration of chlorophyll a (by almost 3.5 times) in late September-early October 2020. This was the main natural factor that led to the development of harmful algal blooms (red tide), which caused the death of hydrobionts both in the Avacha Gulf and in the coastal waters of the entire Kamchatka Peninsula. Based on the results of an analysis of satellite data, it is shown that the possible anthropogenic contribution and contribution of other natural factors to the environmental disaster is insignificant.