Evaluation of performance of Micro Rain Radar over the tropical coastal station Thumba (8.5°N, 76.9°E)

The vertically pointing Micro Rain Radar (MRR) and disdrometer (RD-80) were installed at a coastal station, Thumba (8.5°N, 76.9°E), to study the characteristics of tropical rains. This paper presents the first results from these observations over Thumba and highlights the impact of Mie-scattering corrections to the MRR data for proper estimation of the rainfall intensity. To evaluate the performance of MRR, a total number of 11 Mesoscale Convective Systems events were considered during the period September 2006 to December 2007. The uncorrected MRR shows an overestimation of rain rate and this is larger during the high rain rates. The Mie scattering corrections lead to a decrease in rain rate of the order 2%–31% and resulted in substantial improvement in the rainfall accumulation (368.69 mm (before) to 302.16 mm (after)). The accumulated rainfall is in good agreement with disdrometer total rainfall of 299.14 mm. For the first time, the impact of Mie scattering for different rain categories has been investigated and study shows the rainfall sum significantly improved (about 22%) during the moderate and heavy rain categories whereas, it shows improvement of 11% during the light rain. These studies may be used to estimate the rain attenuation at Ka band over Indian region for different rain categories.