The Impact of Summer Arctic Cyclones on Chlorophyll-a Concentration and Sea Surface Temperature in the Kara Sea

Abstract

In recent years, the intensity of Arctic cyclones has remarkably increased and the impact on the Arctic ecosystem has become more prominent. The Kara Sea is a Russian marginal sea with wide shelf, high productivity of phytoplankton, and abundant resources, and has a very important strategic position and research significance. We have used multiple datasets, including satellite remote sensing data and model reanalysis, to obtain the spatial–temporal distribution of Chlorophyll-a (Chl-a) concentration and sea surface temperature (SST) before and after the passage of the Arctic cyclone over the Kara Sea in summer, to explore basic processes and the ecosystem response to the cyclone. The results indicated that after the passage of the Arctic cyclone, the Chl-a concentration in different regions of the Kara Sea increased at different levels, and the SST decreased briefly. The increase of Chl-a concentration (0.49 mg/m3) caused by the Arctic cyclone happened in Kara Sea in July 2012. The nearshore Chl-a concentration increased more than that on the continental shelf, the continental shelf increases in turn being greater than the deep sea; however, the nearshore response time was shorter than that on the shelf and the deep sea. Compared with nearshore SST, which decreased more than 2 °C, the SST on the continental shelf and in the deep-sea area decreased slightly less. Besides, the left side of the cyclone cooled faster than the right side.