Abstract:The round-trip drifting sounding system (RDSS) can detect the atmospheric temperature profile vertically from ground to the lower stratosphere and the horizontal temperature distribution in the lower stratosphere continuously for 4 hours. Round-trip drifting sounding observation tests have been carried out in the middle and lower reaches of the Yangtze River, Guangdong, Inner Mongolia and other places, and the results are very successful. Based on the data of round-trip drifting sounding tests in the middle and lower reaches of the Yangtze River from March to September 2021, this paper conducts the verification of atmospheric humidity profile data of satellite. The verification results of the descending phase data of the round-trip drifting sounding indicate that the average absolute error of the satellite humidity profile is about 15%, and the root mean square error is approximately 20%. At noon and night, the quality of humidity profile data of satellite is better than that in the morning and evening. The humidity average absolute error of the satellite decreases with increasing altitude and increases with increasing humidity. Below the 50% humidity, the satellite-retrieved humidity is relatively large, but for the humidity above 50%, the satellite-retrieved humidity is relatively small.