The 212.5 MHz Gauhati University stratosphere troposphere radar: system description and first few observations

This article presents the technical overview and initial observations from a novel Stratosphere-Troposphere (ST) radar system recently installed at Gauhati University, Guwahati (26.15° N, 91.66° E). As the first facility of its kind in the northeastern region of India, the radar is poised to significantly enhance our understanding of regional meteorological dynamics, particularly in a region where the onset of the southwest monsoon occurs as early as in mid-May. Starting with overall system configuration, the paper characterizes various subsystems and their functioning. The radar features an open configuration comprising 576 Yagi-Uda antenna elements, arranged in a near-circular aperture following a square grid geometry. Operating at 212.5 MHz, this radar is capable of probing atmospheric layers from 300 m near surface up to 22 km of the lower stratosphere. Utilizing a Doppler Beam Swinging (DBS) technique, the system provides continuous, all-weather, three-dimensional wind measurements. In addition to outlining the system’s technical aspects, the paper presents validation results by comparing radar-derived wind data with collocated GPS radiosonde observations. The radar wind measurements exhibit strong agreement with radiosonde data in both magnitude and direction. The correlation coefficients for zonal and meridional wind components are 0.97 and 0.96, respectively, with corresponding standard deviations of 1.76 ms−1 and 1.80 ms−1. Furthermore, early observational results such as atmospheric boundary layer, precipitation signature, turbulence parameters, etc., demonstrate the radar’s capability for atmospheric monitoring and its potential utility in a wide range of scientific studies.