Assimilation of Feng-Yun-3B Satellite Microwave Humidity Sounder Data over Land  

作　　者：Keyi CHEN Niels BORMANN Stephen ENGLISH Jiang ZHU 

机构地区：[1]School of Atmospheric Sciences, Chengdu University of Information & Technology Chengdu, Sichuan 610225, China [2]International Centre for Climate and Environment Sciences, Institute of Atmospheric Physics, China, Beijing 100029, China [3]European Centre for Medium-Range Weather Forecasts, Reading RG2 9AX, UK

出　　处：《Advances in Atmospheric Sciences》2018年第3期268-275,共8页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 41505014)

摘　　要：The ECMWF has been assimilating Feng-Yun-3B （FY-3B） satellite microwave humidity sounder （MWHS） data over ocean in an operational forecasting system since 24 September 2014, It is more difficult, however, to assimilate microwave observations over land and sea ice than over the open ocean due to higher uncertainties in land surface temperature, surface emissivity and less effective cloud screening. We compare approaches in which the emissivity is retrieved dynamically from MWHS channel l [150 GHz （vertical polarization）] with the use of an evolving emissivity atlas from 89 GHz observations from the MWHS onboard NOAA and EUMETSAT satellites. The assimilation of the additional data over land improves the fit of short-range forecasts to other observations, notably ATMS （Advanced Technology Microwave Sounder） humidity channels, and the forecast impacts are mainly neutral to slightly positive over the first five days. The forecast impacts are better in boreal summer and the Southern Hemisphere. These results suggest that the techniques tested allow for effective assimilation of MWHS/FY-3B data over land.The ECMWF has been assimilating Feng-Yun-3B （FY-3B） satellite microwave humidity sounder （MWHS） data over ocean in an operational forecasting system since 24 September 2014, It is more difficult, however, to assimilate microwave observations over land and sea ice than over the open ocean due to higher uncertainties in land surface temperature, surface emissivity and less effective cloud screening. We compare approaches in which the emissivity is retrieved dynamically from MWHS channel l [150 GHz （vertical polarization）] with the use of an evolving emissivity atlas from 89 GHz observations from the MWHS onboard NOAA and EUMETSAT satellites. The assimilation of the additional data over land improves the fit of short-range forecasts to other observations, notably ATMS （Advanced Technology Microwave Sounder） humidity channels, and the forecast impacts are mainly neutral to slightly positive over the first five days. The forecast impacts are better in boreal summer and the Southern Hemisphere. These results suggest that the techniques tested allow for effective assimilation of MWHS/FY-3B data over land.

关 键 词：data assimilation over land Chinese satellite FY-3B Microwave Humidity Sounder 

分 类 号：P715.7[天文地球—海洋科学]