第七届青年地学论坛

As a result of global warming, multi-year ice (MYI) is being replaced by first-year ice (FYI) in the Arctic. Microwave scatterometers in the Ku-band and C-band can provide daily observations of the sea ice type. However, their comparative capabilities in mapping ice type have not been thoroughly evaluated. In this paper, we present a systematic inter-comparison between the backscatter signature and the sea ice classification from three scatterometer systems using the same ice classification approach. The systems are the Ku-band Quick Scatterometer (QSCAT) and the newly launched Chinese Rotating Fan-beam Scatterometer (RFSCAT) and the C-band Advanced Scatterometer (ASCAT). Three freezing seasons are used, i.e., 2007/08 and 2008/09 for the QSCAT/ASCAT comparison and 2019/20 for the RFSCAT/ASCAT comparison. While the backscatter between the data from each scatterometer pair is found to be correlated, the agreement between RFSCAT and QSCAT is fulfilled only if the RFSCAT backscatter is normalized to the same incidence angle as QSCAT. A continuous declining trend of  from MYI and FYI is observed during winter, with a greater difference between MYI and FYI in the Ku-band. The MYI and FYI extent derived from QSCAT/RFSCAT is highly consistent with that derived from ASCAT, with differences of less than 7% and 3% for MYI and FYI, respectively. The overall accuracy (OA) is around 77% and 80% for the RFSCAT results and ASCAT results, respectively, compared with Sentinel-1 images. The incorporation of  from AMSR-E/AMSR2 improves the OA of the classification when using ASCAT or RFSCAT by 7–11%. The classification results show high consistency (81%-89%) with ice charts from the Canadian Ice Service.

Arctic sea ice,multi-year ice classification,Ku-band scatterometer,C-band scatterometer,RFSCAT