10:45 〜 12:15
[ACG46-P02] Revisiting passive microwave sea ice concentration retrieval using year-round sea ice detection from subsea sonars in the Arctic Ocean
キーワード：海氷密接度、北極海、衛星リモートセンシング
The sea ice concentration (SIC) is an important physical parameter to monitor sea ice extent that is one of the climatic indices associated with the global warming. Its pan-Arctic/Antarctic gridded data set is provided daily based on observations using space-borne passive microwave (PMW) sensors, such as the Advanced Microwave Scanning Radiometer 2 (AMSR2) onboard the Global Change Observation Mission-Water (GCOM-W). The PMW-SIC algorithms have been developed using microwave emissivity changes depending on an Earth’s surface type in polar oceans. However, the algorithms developed with a particular focus on cold and dry winter months degrade their performances in warm and wet summer months, despite the growing demands for satellite sea ice products to assist the Arctic shipping during summer sea ice retreats. To improve the algorithms, a temporally successive validation is required to identify specific conditions in which the PMW-SIC retrieval is degraded; however, optical sea ice observations widely used for validating the PMW-SIC are limited to clear-sky conditions.
In this study, we introduce a novel approach for validating the PMW-SIC using upward-looking subsea sonar measurements that provide time series of sea ice existences at the specific locations in the Arctic Ocean without atmospheric effects. The sonar measurements monitored bottom topographies of the passing ice floe in seconds, as well as sea ice velocities in hours, so that the combined use of the two data records enables us to acquire spatial distributions of sea ice thickness including appearances of ice-free ocean surfaces by ice opening. In the presentation, we will show detailed comparison results between in situ and satellite SIC values.
In this study, we introduce a novel approach for validating the PMW-SIC using upward-looking subsea sonar measurements that provide time series of sea ice existences at the specific locations in the Arctic Ocean without atmospheric effects. The sonar measurements monitored bottom topographies of the passing ice floe in seconds, as well as sea ice velocities in hours, so that the combined use of the two data records enables us to acquire spatial distributions of sea ice thickness including appearances of ice-free ocean surfaces by ice opening. In the presentation, we will show detailed comparison results between in situ and satellite SIC values.