尹若莹,韩威,高志球,王根. 2019. 基于风云四号A星探测区域模式背景误差和观测误差估计的长波红外通道选择研究[J]. 气象学报, (0):-, doi:10.11676/qxxb2019.051
基于风云四号A星探测区域模式背景误差和观测误差估计的长波红外通道选择研究
Study on longwave infrared channel selection based on background error and observation error estimation in the observation range of FY-4A
投稿时间:2018-09-10  修订日期:2018-12-17
DOI:10.11676/qxxb2019.051
中文关键词:  风云四号A星,干涉式大气垂直探测仪,通道选择,背景误差协方差,观测误差
英文关键词:FengYun 4A, GIIRS, Channel selection, Background error covariance, Observation error
基金项目:国家自然科学基金
作者单位E-mail
尹若莹 中国科学院大气物理研究所中国气象局数值预报中心中国科学院大学 yinruoying15@mails.ucas.edu.cn 
韩威 中国气象局数值预报中心国家气象中心 hanwei@cma.gov.cn 
高志球 中国科学院大气物理研究所 zgao@mail.iap.ac.cn 
王根 安徽省气象信息中心 203wanggen@163.com 
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中文摘要:
      中国新一代静止气象卫星风云四号A星上搭载的干涉式大气垂直探测仪GIIRS(Geostationary Interferometric Infrared Sounder)是世界上首台在静止轨道运行的高光谱红外探测仪器,拥有1650个通道,其中长波通道689个,中波通道961个。[目的]由于计算机存储能力、数据传输和变分同化时效性等限制,目前很难在业务环境中同化全部通道,并且多通道卫星信息往往存在一定的空间相关性和光谱相似性,故在实际应用中必须降低高光谱资料的通道维数,去除数据冗余和观测相关性,挑选出对特定目标起主要作用的通道子集,进而利用有限的通道来最大限度地提供观测信息。[资料和方法]考虑GRAPES(Global/Regional Assimilation and Prediction Enhanced System)数值预报系统估计得到的风云四号A星观测范围内的背景误差协方差矩阵,并且在GIIRS观测误差后验重估计的基础上,结合通道权重函数峰值和信息熵分步迭代法对其长波通道进行了通道选择研究和试验。[结果]与[结论]试验结果表明:在给定选择通道个数时,权重函数法和信息熵方法得到的通道组合进行温度和湿度误差分析时误差整体比单一方法小,在给定通道个数(40个)少于单一方案(50个)时,误差分析结果相当。GIIRS最优通道选择的研究为该资料的同化应用建立了基础。
英文摘要:
      Geostationary Interferometric Infrared Sounder(GIIRS) is on board the FY-4A, which is the new generation of Chinese geostationary weather satellites. It is the first high-spectral-resolution advanced Infrared sounder on board a geostationary weather satellite in the world. It has 1650 spectral channels to cover long-wave infrared (689 channels) and middle-wave infrared (961 channels) bands. Due to the limitations of computer storage capacity, data transmission and variational assimilation timeliness, it is difficult to assimilate all the channels in the operational assimilation system. On the other hand, the multi-channel satellite information often has some spatial correlation and spectral similarity, so it is necessary to reduce the channel dimension of hyper-spectral data and remove data redundancy in practical applications. The subset of channels that play a major role in a particular target is used to provide maximum observation information. For long-wave channels of GIIRS, an experiment on its channel selection is carried out by combining the weighting function peaks and information entropy, considering the observation error re-estimation and background error covariance in the observation range of FY-4A based on operational Global/Regional Assimilation and Prediction Enhanced System(GRAPES). Research results show that: it is very essential to rationally choose the channels when retrieving atmospheric temperature with GIIRS data. On the other hand, the method of combining the weighting function peaks and information entropy is better than single method when the numbers of channel combination is same. And the reduction of atmospheric temperature and humidity error are almost the same when the numbers of channel combination obtain from combination method (40 channels) are smaller than others(50 channels). This study will lay a foundation for the application of GIIRS in the variational assimilation system.
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