Evaluation of Doppler weather radar MEGHA-2700 observations using Gematronik Doppler weather radar and TRMM Precipitation Radar

As a part of the MEGHA-2700 validation after programme, Doppler weather radar (DWR) at Sriharikota (13.66 degrees N, 80.23 degrees E) is validated with the Chennai (13.07 degrees N, 80.28 degrees E DWR) (hereafter CHENNAI-DWR) and simultaneous observations along with Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) measurements. Many simultaneous observations of weather systems were carried out using these two DWRs with an aim of validating the MEGHA-2700. During this validation period, a tropical cyclone 'OGNI' formed in the Bay of Bengal on 28 October 2006. Simultaneous observations from these two radars are used for the present study along with TRMM-PR measurements. A methodology is developed to interpolate two ground radars and PR volume scans into a fixed Cartesian grid box because the common volume observations minimize uncertainties associated with the sampling volumes and viewing angles. It is observed that MEGHA-2700 systematically underestimates CHENNAI-DWR reflectivity by similar to 6.23 dB. The rainfall estimations from MEGHA-2700 show that the bias adjustment reduces the total rainfall differences significantly between radar estimates and rain gauges. The significance of the present study lies in validating the indigenously developed DWR, which will form the basis for further research on cloud microphysics.