Raindrop size distribution of different cloud types over the Western Ghats using simultaneous measurements from Micro-Rain Radar and disdrometer

Investigating the raindrop size distributions (DSDs) for different cloud types is essential for the rain characterization and understanding different microphysical processes within the cloud system. In this study, the simultaneous measurements from the Micro-Rain Radar (MRR) and Joss-Waldvogel Disdrometer (JWD) are used to investigate the DSDs of different precipitation categories during the Indian Summer Monsoon (ISM) season (June-September) for the period 2012-2015. Both the instruments deployed at Mahabaleshwar (17.92°N, 73.6°E, ~ 1.4 km AMSL), which is located in the complex mountain terrain of the Western Ghats (WGs), India. From the MRR reflectivity factor and fall-velocity profiles, the observed precipitation systems are classified into four categories: shallow-convective, convective, stratiform and mixed convective-stratiform. In terms of rain occurrence frequency, it is found that the rain over Mahabaleshwar is mostly contributed by the shallow-convective (~ 89%) system while the stratiform system contribution is about 9% and the convective and the mixed convective-stratiform systems contributes < 2%. For different precipitation categories, the rain microphysical parameters such as median volume diameter, rain liquid water content and normalized intercept parameter are estimated using the moment method (second, third and fourth moment) of the observed DSDs. The reflectivity-rainfall (Z-R) relation of the form Z = aRb is estimated for each precipitation categories. Studies of systematic and comprehensive classification of precipitation types in terms of their rain microphysical parameters and Z-R relationships over a region is important as it would improve the understanding on rain microphysics and rainfall estimation from active and passive remote sensing devices.