Evaluation of DBS Wind Measurement Technique in Different Beam Configurations for a VHF Wind Profiler

Atmospheric winds in the troposphere have been observed routinely for many years with wind profiling ( VHF and UHF) radars using the Doppler beam swinging ( DBS) technique. Accuracy of wind estimates using wind profiling radars with different beam configurations has its limitations due to both the system of observation and atmospheric conditions. This paper presents a quantitative analysis and evaluation of horizontal wind estimation in different beam configurations up to an altitude of 18 km using the mesosphere-stratosphere-troposphere ( MST) radar located in Gadanki, India. Horizontal wind velocities are derived in three different ways using two-, three-, and four-beam configurations. To know the performance of each configuration, radar-derived winds have been compared with the winds obtained by simultaneous GPS sonde balloon measurements, which are considered to be a standard reference by default. Results show that horizontal winds measured using three different beam configurations are comparable in general but discrepancy varies from one beam configuration to the other. It is observed that horizontal winds measured using four-beam configuration ( east, west, north, and south) have better estimates than the other two- beam configurations. The standard deviation was found to be varying from 1.4 to 2.5 m s(-1) and percentage error is about 9.68%-12.73% in four-beam configuration, whereas in other beam configurations the standard deviation is about 1.65-3.9 m s(-1) and the percentage error is about 11.29%-15.16% with reference to GPS sonde balloon-measured winds.