摘要
微波湿温探测仪(MWHTS)的通道响应函数(SRF)一般被认为近似于矩形函数,然而从实际SRF的测试数据来看,MWHTS各个频段不同通道的SRF存在一定的带内波动。本文利用大气辐射传输模拟器(ARTS)模拟了MWHTS中118 GHz各通道不同场景的亮温谱,并输入至前期建立的MWHTS系统仿真模型中,通过定标得到了仪器的输出亮温,进而评估实测SRF对亮温测量及其反演的大气温度廓线的影响,并利用卫星实测数据进行了对比验证。结果表明,亮温偏差与实际SRF的带内波动呈现线性正相关的关系,当带内波动大于3 dB时,亮温偏差可以达到0.2—0.5 K。SRF的带内波动会造成大气温度廓线反演误差,特别是在高度为1.8 km时,误差最大可以达到0.8—0.9 K,该仿真结果与卫星实测数据结果一致。因此在使用数据同化方法对数值天气预报(NWP)进行模拟时,需要特别注意具有较大SRF带内波动的通道所引起的亮温偏差,这对于未来卫星数据的应用具有重要的研究价值。
The shapes of the channel Spectral Response Function(SRF) of Microwave Humidity and Temperature Sounders(MWHTS) are generally considered to be approximately rectangular. However, the SRF of each band channel of MWHTS shows certain in-band fluctuations based on the actual SRF test data. In this paper, the brightness temperature spectra of different scenarios for each channel at 118GHz of MWHTS are simulated using an Atmospheric Radiative Transfer Simulator(ARTS). After inputting them into the MWHTS system simulation model we established in the previous stage, the output brightness temperature of the instrument is obtained after calibration, the influences of actual SRF on brightness temperature measurements and the retrievals of atmospheric temperature profiles are evaluated, and comparisons are further made with the actual satellite data of MWHTS in FY-3D to verify the results. The results show that the brightness temperature bias is linearly and positively correlated with the in-band fluctuations of SRF. The bias can reach 0.2—0.5 K in the 118 GHz channel when the actual SRF in-band fluctuations are larger than 3 dB. The in-band fluctuations of SRF will cause retrieval errors in the atmospheric temperature profiles, especially at an altitude of 1.8 km, where the retrieval error can reach the maximum value of 0.8—0.9 K.The simulation results are consistent with the results of the actual satellite data, so special attention needs to be paid to the bias in the simulated brightness temperature of the channels with large SRF fluctuations in applying simulations for Numerical Weather Prediction(NWP) using data assimilation methods, which has important research value for the future application of satellite data.
作者
王振占
许皓文
段永强
王文煜
丁甲
何文明
张升伟
WANG Zhenzhan;XU Haowen;DUAN Yongqiang;WANG Wenyu;DING Jia;HE Wenming;ZHANG Shengwei(Key Laboratory of Microwave Remote Sensing,National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《遥感学报》
EI
CSCD
北大核心
2023年第2期394-405,共12页
NATIONAL REMOTE SENSING BULLETIN
基金
国家自然科学基金(编号:41771405)。
关键词
遥感
风云三号气象卫星D星
微波湿温探测仪
通道响应函数
亮温偏差
温度廓线反演
remote sensing
FY-3D meteorological satellite
microwave humidity and temperature sounder
spectral response function
brightness temperature bias
retrieval of temperature profiles
