Spatial and Temporal Variability of Minimum Brightness Temperature at the 6.925 GHz Band of AMSR2 for the Arctic and Antarctic Oceans

Remote Sensing

SeungHee Kim¹  Jeong-Won Park¹  Jong-Min Kim¹  Hyun-Cheol Kim¹  Young-Joo Kwon¹  Sungwook Hong² 

[1] Center of Remote Sensing and GIS, Korea Polar Research Institute, Incheon 21990, Korea;Department of Environment, Energy and Geoinfomatics, Sejong University, 209 Neungdongro, Gwangjin-gu, Seoul 05006, Korea;

关键词: passive microwave;    ocean;    AMSR2;    tie point;    Arctic amplification;   

DOI  :  10.3390/rs13112122

来源: DOAJ

【 摘 要 】

The minimum brightness temperature (mBT) of seawater in the polar region is an important parameter in algorithms for determining sea ice concentration or snow depth. To estimate the mBT of seawater at 6.925 GHz for the Arctic and Antarctic Oceans and to find their physical characteristics, we collected brightness temperature and sea ice concentration data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) for eight years from 2012 to 2020. The estimated mBT shows constant annual values, but we found a significant difference in the seasonal variability between the Arctic and Antarctic Oceans. We calculated the mBT with the radiative transfer model parameterized by sea surface temperature (SST), sea surface wind speed (SSW), and integrated water vapor (IWV) and compared them with our observations. The estimated mBT represents the modeled mBT emitted from seawater under conditions of 2–5 m/s SSW and SST below 0 °C, except in the Arctic summer. The exceptional summer mBT in the Arctic Ocean was related to unusually high SST. We found evidence of Arctic amplification in the seasonal variability of Arctic mBT.

【 授权许可】

Unknown