中法海洋卫星微波散射计海冰区后向散射系数时空变化特征  

Spatial and temporal characteristics of CSCAT backscattering coefficient over sea ice zone

作　　者：羊丽青 林文明 YANG Liqing;LIN Wenming(School of Marine Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,China;Key Laboratory of Space Ocean Remote Sensing and Applications,Ministry of Natural Resources,Beijing 100081,China)

机构地区：[1]南京信息工程大学海洋科学学院,江苏南京210044 [2]自然资源部空间海洋遥感与应用重点实验室,北京100081

出　　处：《海洋气象学报》2024年第4期76-90,共15页Journal of Marine Meteorology

基　　金：国家重点研发计划项目(2022YFC3104900,2022YFC3104902)。

摘　　要：以往基于微波散射计的海冰遥感研究主要是进行海冰和海水的区分,进而探究海冰的覆盖范围。中法海洋卫星(China-France Oceanography SATellite,CFOSAT)散射计(SCATterometer,简记为“CSCAT”)利用扇形波束旋转扫描对地面进行观测,其多入射角和多方位角的观测几何特点为海冰监测提供了新机遇。首先将CSCAT后向散射系数数据与欧洲气象卫星应用组织的海冰密集度(sea ice concentration,SIC)数据进行匹配,其次分析南北两极不同海冰密集度下CSCAT后向散射系数的季节性变化,厘清CSCAT海冰后向散射系数的时空分布特征,为后续构建海冰后向散射地球物理模式函数(Geophysical Model Function,GMF)奠定基础。结果表明,CSCAT后向散射系数随海冰密集度的增加而增强。海冰密集度较低时,CSCAT在南北两极的后向散射系数具有良好的一致性,但存在明显的风速调制效应,且该效应随着海冰密集度的增加逐渐减弱。研究结果为利用扇形波束旋转扫描散射计进行海冰密集度遥感提供参考。Previous studies on the sea ice remote sensing based on microwave scatterometers mainly focus on distinguishing sea ice from sea water,and in turn,exploring the coverage of sea ice.The scatterometer onboard China-France Oceanography SATellite(CFOSAT),namely CSCAT,uses rotary fan beams to observe the earth surface,such that its multi-incidence and multi-azimuth observation geometry provides new opportunities for sea ice monitoring.In this study,the CSCAT backscattering coefficient data are firstly collocated with the sea ice concentration(SIC)data from European Organisation for the Exploitation of Meteorological Satellites(EUMETSAT),and then the seasonal variations of the CSCAT backscattering coefficient under different SIC conditions in the Arctic and Antarctic are analyzed.Consequently,the spatial and temporal characteristics of the CSCAT backscattering coefficient over the sea ice zones are derived,which provide a foundation for developing a sea ice geophysical model function(GMF).The results show that the CSCAT backscattering coefficient increases with SIC.Under low SIC condition,the CSCAT backscattering coefficient shows good consistency in the Arctic and Antarctic,but there is an obvious modulation by wind speed,whose effect weakens as the SIC increases.In summary,the study provides relevant hints for the SIC retrieval using the scatterometer with fan-beam rotary scanning system.

关 键 词：中法海洋卫星(CFOSAT) 散射计 海冰密集度(SIC) 后向散射系数 时空分布特征 

分 类 号：P715.6[天文地球—海洋科学]