Cloud Liquid Water Content and Cloud Attenuation Studies with Radiosonde Data at a Tropical Location

Abstract

The profile of cloud liquid water density and the total liquid water content (LWC) are obtained from the radiosonde data using the Salonen model at Kolkata, India, a tropical location. The cumulative distribution LWC shows a departure from the ITU-R model at this location, exhibiting a significantly enhanced occurrence during the monsoon months. The cloud attenuation, derived by integrating the profile of specific attenuation obtained from the radiosonde data, is related to LWC at different frequencies in the range 10-100 GHz. A comparison indicates that the cloud attenuation at frequencies below 50 GHz is somewhat overestimated by the ITU-R model generated values and significantly underestimated by the ITU-R model at frequencies above 70 GHz at the present location.