Studies of radar bright band using UHF radar at Gadanki

In the present study Lower Atmospheric Wind Profiler (LAWP) operating at a frequency of 1.3 GHz is installed at Gadanki (13.50°N, 79.20°E) is used to study the characteristics of radar Bright Band. Radar observations of the melting layer of precipitation have been made from few decades. It has been known since then that the melting of precipitation is often associated with an increase of the reflectivity of weather targets. The primary cause for this is a rapid increase in the dielectric constant of hydrometeors at the top of the melting layer followed by an increase of the fall velocities of melting snowflakes towards the end of the melting process. VHF/UHF radars can also be used to study radar bright band, a strong enhancement in reflectivity at around 0°C isotherm level. Using VHF/UHF radars bright band structure are studied particularly in the tropics. Though lot of work has been done on the radar signature of the melting layer, still microphysics behind its formation possesses a challenging task to the atmospheric scientists. The ability of the profilers to clearly resolve and identify the melting layer when it is present gives very good information regarding the classification of various precipitating systems within the Tropical Mesoscale Convective Systems (TMCS). VHF/UHF radars are the wonderful tools in classifying the systems. LAWP data during the period of March 1999 to September 2000 used for the present study. Dependency of bright band height and thickness on various parameters is investigated. An automated bright band detection algorithm is made to detect the height and thickness of bright band. It is compared well with the radiosonde observations. A statistical study has been done in correlating bright band thickness with that of the precipitation intensity. Further in the present paper altitude variation of bright band with the seasons are calculated.