Feature Extraction of Hill Rain on the Basis of Reflectivity-Rain Rate Relationship

An insight into the global hydrological cycle which is an important controlling factor of ecological system, requires the microphysical properties of rain to be understood very clearly. To estimate rain fall rate, Radar reflectivity (Z) and rainfall rate (R) relationship is a preferred choice. Therefore it is necessary to study the microphysical property of rain with a special focus in hills besides the plane land in tropical region as topography has a major impact on local weather. Here the place under investigation, Majhitar, Sikkim is having 200 metres of altitude and surrounded by hills. Rain events are separated into convective and stratiform type using Gamache-Houze method. Radar reflectivity is extracted from LASER Precipitation Monitor (LPM) data at Sikkim Manipal Institute of Technology (SMIT) site for one whole month (August, 2019) rain events. The Z–R relation for Sikkim is established and a clear deviation from Marshall—Palmer and Rosenfeld proposed model is reported. The variation in the pattern of convective and stratiform rain presented in the work is clear evidence of high altitude effect and the terrain of hill is introducing signature of orographic rain with the conventional rain also.