Comparison of Atmospheric Temperature and Humidity Sounding by Different Sensors Onboard a New Composite Wing UAV

Abstract

Satellite navigation-based autonomous drones have become an important platform for atmospheric exploration. In order to overcome the harsh take-off and landing conditions of fixed-wing UAVs and the short flight time of rotorcraft, a new composite wing UAV with rotary and fixed-wing has been developed by Middle Atmosphere and Global Environment Exploration Laboratory of Institute of Atmospheric Physics, Chinese Academy of Sciences. Two field experiments of UAV soundings are carried out in Zhengxiangbaiqi, Inner Mongolia from 28 July to 6 August in 2020 and from 1 August to 6 August in 2021 to examine the performance of sounding sensors onboard the new type of UAV. The instruments used and the experiments conducted in the two phases of the experiment are introduced first, and then the temperature and relative humidity profile data obtained by different sensors onboard the UAV are compared and analyzed. The results show that the temperature bias between the AWS and the GPS radiosonde onboard UAV is about 2.00 to 2.35℃; the systematic deviation can be revised, and the correlation coefficient is 0.98. The deviation of relative humidity is 4.28% and the correlation coefficient is 0.84 in 2020. The Vaisala temperature and humidity probe are onboard the UAV in the experiment of 2021, which are in good agreement with GPS radiosonde, but the AWS is vastly different from both. The flight sounding test shows that the long-endurance composite wing UAV with rotary and fixed-wing can obtain meteorological information in the near-surface atmosphere because of its larger vertical and horizontal range than the conventional rotary-wing UAV. The AWS onboard new composite wing UAV can obtain temperature and humidity profile information of the near-surface atmosphere, but the time lag effect caused by fast descent speed is obvious. Therefore, the sensor with obvious time lag effect is not suitable for the sounding of faster flight speed. The flight attitude change and turn of the UAV in the level flight process have no obvious effects on the measurements of temperature and humidity.