Comparing upper tropospheric humidity from microwave satellite instruments and IGRA radiosonde data

In this study, Advanced Microwave Sounding Unit (AMSU-B) and Microwave Humidity Sounder (MHS) observations are compared to radiosonde data from the Integrated Global Radiosonde Archive (IGRA) dataset. This comparison can be used to evaluate the overall quality of the radiosonde data. Microwave satellite data are influenced by thick ice clouds and radiosonde data show a day-time radiation dry bias. Therefore, we used night-time cloud-free data of the year 2009 for the comparison. Overall, radiosonde data from the former Soviet Union were up to 30 %RH moister than satellite data and the the rest of the world were up to 6 %RH drier than satellite data.