Verifying The Radiosonde Humidity Sensor Performance

Monitoring the performance of humidity sensors has become particularly relevant due to the lack of in-house production of humidity sensors in the Russian Federation and the logistical problems that have arisen. Humidity is subject to high spatial variability, therefore, standard methods for monitoring data quality based on the difference with the field of the first approximation are not applicable for its control. It is proposed to carry out monitoring by comparing readings on the surface and at altitude with a pressure of 850 hPa, where humidity is less than 60% in the absence of low clouds, and more than 70% in its presence. The fact of the presence/absence of low clouds is determined by the readings of a vertically oriented pyrometer. The difference between the air temperature at the surface and the temperature from the pyrometer of more than 14°K corresponds to the absence of low clouds, and less than 14°K corresponds to the presence of low clouds. Accordingly, a serviceable humidity sensor should show the appropriate values.