气象科技进展Issue(4)：50-59,10.DOI:10.3969/j.issn.2095-1973.2013.04.006
运用主成分分析方法诊断和消除风云三号B星微波湿度计观测数据中的噪音
Fengyun-3B MicroWave Humidity Sounder (MWHS) Data Noise Characterization and Filtering Using Principle Component Analysis
摘要
Abstract
MicroWave Humidity Sounder (MWHS) onboard both Fengyun-3A (FY-3A) and FY-3B satellites have three channels (channels 3-5) near the 183-GHz water-vapor absorption line. These channel frequencies are also used in other instruments such as Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) onboard MetOp and NOAA satellites. Both MWHS and MHS are cross-track scanners. In this paper, a comparison between the simulated brightness temperatures with MWHS measurements clearly shows that MWHS observations from the three sounding channels contain a scan-angle-dependent cohesive noise along the instrument scanline. This noise does not cancel out when a large amount of data over a sufifciently long period of time is averaged, which eliminates the possibility of such a noise to arise from the natural variability of the atmosphere and the surface. The noises are around 0.3, 0.2, and 0.2 K for channels 3-5, respectively. A principle component analysis is used for the characterization of this cohesive noise using one-month FY-3B MWHS data. It is shown that the MWHS cohesive noise is primarily contained in the ifrst principal component (PC) mode, which mainly describes a scan-angle-dependent brightness temperature variation, i.e., a unique feature of the cross-tracking instrument. The ifrst PC accounts for more than 99.91%total variance in the three MWHS sounding channels. A ifve-point smoother is then applied to the ifrst PC, which effectively removes such a data noise in the MWHS data. The reconstruction of the MWHS radiance spectra using the noise-ifltered ifrst PC component is of good quality. The scan-angle-dependent bias from the reconstructed MWHS data becomes more uniform and is consistent with the NOAA-18 MHS data.关键词
风云三号B星(FY-3B)/微波湿度计(MWHS)/微波湿度计(MHS)/主成分分析方法Key words
Fengyun-3B (FY-3B)/MicroWave Humidity Sounder (MWHS)/Microwave Humidity Sounder (MHS)/principal component analysis (PCA)引用本文复制引用
邹晓蕾,马原,秦正坤..运用主成分分析方法诊断和消除风云三号B星微波湿度计观测数据中的噪音[J].气象科技进展,2013,(4):50-59,10.基金项目
国家重点基础研究发展计划（973计划）项目（2010CB951600和2009CB421500）；美国NSF项目（AGS-1037936）；公益性行业（气象）科研专项 （）
