Importance of air pressure in the compensation for the solar radiation effect on temperature sensors of radiosondes

Abstract

Solar radiation affects temperature measurements by radiosondes considerably in the upper air. In the present study, the effect of both radiation intensity and air pressure on the temperature measurement of radiosonde sensors, as well as reference temperature sensors for comparison, was studied using a home-built chamber allowing light transmission and pressure control. Temperature measurements were conducted both in the illuminated area and the shaded area inside the radiosonde chamber and the temperature difference (ΔT) between the two was considered for the compensation of radiation. It was found that the temperature difference is linearly proportional to the radiation intensity experimentally as well as theoretically. The effect of air pressure is significant in such a way that the temperature difference rapidly increases up to about 5.5 K under 356.5 W m−2 as the air pressure is decreased down to 1 kPa. The characteristic behaviours of the pressure-dependent temperature deviation are explained by heat transfer equations. The present study emphasizes the importance of considering both radiation intensity and air pressure in efforts to calibrate radiosonde sensors for the solar radiation effect using ground facilities.