AMSR-2性能改进对无线电频率干扰的有效缓解  

Effective mitigation of radio frequency interference by AMSR-2 instrument performance improvement

作　　者：官莉[1] 张渝晨 GUAN Li;ZHANG Yuchen(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China;Henan Institute of Meteorological Science,Zhengzhou 450003,China)

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心,南京210044 [2]河南省气象科学研究所,郑州450003

出　　处：《电波科学学报》2020年第6期935-942,共8页Chinese Journal of Radio Science

基　　金：国家自然科学基金(41975028)。

摘　　要：为缓解星载微波辐射计探测资料在低频6.9 GHz波段的无线电频率干扰(radio frequency interference,RFI),第二代先进的微波扫描辐射计(advanced microwave scanning radiometer-2,AMSR-2)在AMSR-E通道设置的基础上增加了中心频率为7.3 GHz的两个极化通道.除此之外,AMSR-2在硬件方面将天线反射器的直径由1.6 m扩大为2.0 m,并减小了各通道的波束宽度.本文基于AMSR-E 2010-10—2011-09(AMSR-E工作最后一年)和AMSR-22012-08—2013-07(AMSR-2工作第一年)、2016-08—2017-07(AMSR-2工作四年后)长时间序列的观测资料通过平均值标准差法识别全球陆地6.9 GHz和7.3 GHz通道的无线电频率污染.研究结果表明,AMSR-27.3 GHz观测资料中识别出的RFI污染像元数量上远小于AMSR-E 6.9 GHz观测资料中受污染像元个数,尤其是美国和日本地区,体现了新增通道对RFI的有效缓解.AMSR-2在硬件方面的改进增大了主波束效率,提高了空间分辨率;与AMSR-E共有的6.9 GHz通道相比,全球RFI从出现范围和强度上都有所减小.With the development of microwave remote sensing technology,the measurements of spaceborne microwave radiometer have been widely used in atmospheric research.However,data from these sensors are often contamined by Radio Frequency Interference(RFI),which reduce the utilization of microwave measurements,especially for the low frequency observations.In order to mitigate the RFI in spaceborne microwave measurements at 6.9 GHz channel,two new channels centered at 7.3 GHz are added in Advanced Microwave Scanning Radiometer-2(AMSR-2)based on AMSR-E.Moreover,AMSR-2 also has a larger diameter antenna reflector(2.0 m compared to 1.6 m for AMSR-E)and narrower beam width than AMSR-E.To make an evaluation about whether AMSR-2's hardware improvements and two new channels mitigate the RFI in microwave measurements,AMSR-2 and AMSR-E observations at 6.9 GHz and 7.3 GHz from August 2012 to July 2013,August 2016 to July 2017 and October 2010 to September 2011 over global land are analyzed using the means and standard deviation method in this paper.Research results show that the number of RFI-contaminated pixels in AMSR-2 at 7.3 GHz observations is much less than that in AMSR-E at 6.9 GHz observations,especially in the United States and Japan.At the same time,AMSR-2 hardware improvement increases the main beam efficiency and improves the spatial resolution.Comparing with AMSR-E the field of view number of RFI in AMSR-2 at 6.9 GHz observations has a decrease both in range and intensity.It can be concluded that the hardware improvement and two new added channels indeed mitigate AMSR-2 RFI contamination in C band,especially in the United States and Japan.Moreover,the distribution of RFI at 6.9 GHz is quite different from that at 7.3 GHz.Therefore,observations of the two channels can effectively be complemented each other when inverting the geophysical parameters.

关 键 词：AMSR-2 AMSR-E 长时间序列 微波遥感 无线电频率干扰(RFI) 

分 类 号：P407.7[天文地球—大气科学及气象学]