Asha Nath

Validation of ground-based microwave radiometer data and its application in verifying atmospheric stability over Mahbubnagar during 2011 monsoon and post-monsoon seasons

Atmospheric instabilities, mainly convection, depend on temperature distribution and moisture availability. The development of convection can often lead to the formation of clouds and precipitation, release of latent heat, etc. The initiation or development of instabilities has to be studied in detail with high-resolution, ground-based instruments such as ground-based microwave radiometric measurements. In this study we evaluated ground-based microwave radiometer data (MWR)-retrieved temperature and relative humidity profiles and compared these to radiosonde observations. Analysis showed that MWR-measured temperature (specific humidity) has a warm (wet) bias below 3 km and cold (dry) bias above that altitude. Correlation of stability indices estimated from radiometer and radiosonde showed fairly good correlation, with a correlation coefficient greater than 0.5 with 95% significance. MWR was then utilized for the verification of atmospheric stability over Mahbubnagar (16° 44′ N, 77° 59′ E), India, during the second half of the monsoon and start of post-monsoon seasons. Radiometric observations showed strong day-to-day variation of atmospheric parameters as well as thermodynamic indices during the monsoon, which were weak during the post-monsoon season. The seasonal mean of thermodynamic indices and the associated seasonal difference showed that thunderstorm potential is higher during the post-monsoon season over the study site.