09:00 〜 10:30
[ACG37-P08] Analysis of Interannual Variation in Phytoplankton Blooms Associated with Environmental Changes in the Bering Sea and Chukchi Sea Using GCOM-C/SGLI
キーワード：GCOM-C/SGLI、ベーリング海、海色、植物プランクトン
The northern Bering Sea and the southern Chukchi Sea, which connect the Pacific Ocean and the Arctic Ocean via the Bering Strait, are recognized as high productivity region in the world. The upwelling of anadir water flowing from the Pacific Ocean along the western coast provides abundant nutrients to the surface layer. This upwelling event causes phytoplankton blooms in the spring, during the sea ice melting season.
In previous studies, environmental change analysis in the Bering Sea and Chukchi Sea using satellite observation has been conducted. However, due to the low spatial resolution of the ocean color sensor, it has been difficult to analyze in detail the relationship between the upwelling of anadir water or the melting of sea ice and the occurrence of phytoplankton blooms. In particular, the significant decrease in annual mean sea ice concentration in the Bering Sea that occurred in the spring and summer of 2018 and the ecosystem response to this change in the marine environment have not yet been fully studied [1].
In this context, the GCOM-C/SGLI ocean color sensor, which can observe coastal areas with a high spatial resolution of 250 m, was launched by JAXA on December 23, 2017.SGLI is expected to monitor ocean phenomena on smaller scales that have been difficult to observe with previous satellites. SGLI's high-resolution images of local marine environmental changes in the Bering and Chukchi Seas in 2018 are expected to make a significant contribution to studies assessing the impact of climate change on polar ecosystems.
Therefore, in this study, we analyzed the detailed annual spatial distribution variability of sea ice concentration and sea surface temperature for the years 2018 to 2022, when the ocean environment in the Bering Sea and Chukchi Sea is rapidly changing. We also analyzed how those interannual variations affect the timing and magnitude of spring and fall phytoplankton blooms. As a result, we confirmed that in Anadyr Bay, the scale of the spring phytoplankton bloom was larger and the timing of its occurrence was earlier in 2018 and 2019, when the sea ice retreat was relatively early. Furthermore, high-resolution SGLI observations allowed us to clearly observe the upwelling event in the Bering Strait and the increase in primary production associated with nutrient supply to the surface layer due to the upwelling.
[1] Hirawake, Toru, and George L. Hunt Jr. "Impacts of unusually light sea-ice cover in winter 2017-2018 on the northern Bering Sea marine ecosystem–An introduction." Deep Sea Research Part II: Topical Studies in Oceanography 181 (2020): 104908.
In previous studies, environmental change analysis in the Bering Sea and Chukchi Sea using satellite observation has been conducted. However, due to the low spatial resolution of the ocean color sensor, it has been difficult to analyze in detail the relationship between the upwelling of anadir water or the melting of sea ice and the occurrence of phytoplankton blooms. In particular, the significant decrease in annual mean sea ice concentration in the Bering Sea that occurred in the spring and summer of 2018 and the ecosystem response to this change in the marine environment have not yet been fully studied [1].
In this context, the GCOM-C/SGLI ocean color sensor, which can observe coastal areas with a high spatial resolution of 250 m, was launched by JAXA on December 23, 2017.SGLI is expected to monitor ocean phenomena on smaller scales that have been difficult to observe with previous satellites. SGLI's high-resolution images of local marine environmental changes in the Bering and Chukchi Seas in 2018 are expected to make a significant contribution to studies assessing the impact of climate change on polar ecosystems.
Therefore, in this study, we analyzed the detailed annual spatial distribution variability of sea ice concentration and sea surface temperature for the years 2018 to 2022, when the ocean environment in the Bering Sea and Chukchi Sea is rapidly changing. We also analyzed how those interannual variations affect the timing and magnitude of spring and fall phytoplankton blooms. As a result, we confirmed that in Anadyr Bay, the scale of the spring phytoplankton bloom was larger and the timing of its occurrence was earlier in 2018 and 2019, when the sea ice retreat was relatively early. Furthermore, high-resolution SGLI observations allowed us to clearly observe the upwelling event in the Bering Strait and the increase in primary production associated with nutrient supply to the surface layer due to the upwelling.
[1] Hirawake, Toru, and George L. Hunt Jr. "Impacts of unusually light sea-ice cover in winter 2017-2018 on the northern Bering Sea marine ecosystem–An introduction." Deep Sea Research Part II: Topical Studies in Oceanography 181 (2020): 104908.