Study on deep inland penetration of sea breeze over complex terrain in the tropics

Abstract

Characteristics of sea breeze circulations over a tropical Indian station have been studied, based on one year of observations, by Doppler Sound Detection and Ranging (SODAR) system at National Atmospheric Research Laboratory, Gadanki (13.5°N, 79.2°E), India. The effect of sea breeze circulations on the dynamics of low level flow patterns in atmospheric boundary layer over complex terrain in tropics is investigated. The study reveals that a sea-breeze front develops well along the eastern coastal plain of southern peninsular India and propagates over inland up to the distance about 80km. It is found that the sea-breeze signal is well recognized during the months of February, March and April due to the presence of tropical easterlies. In these three months, SODAR observations indicate a late afternoon intensification of sea-breeze flow in the height range 0.2–0.6km during 1400 and 2000 local time (LT). The decrease in temperature of 2°C and increase in relative humidity of 20% at surface level are observed on a sea breeze day as compared to a non-sea breeze day. Sea-breeze inland propagation is absent for the rest of the months due to the opposing meso-flow direction. ERA-Interim reanalysis U-velocity data over south-Asia grid also corroborates the deep-inland penetrations of sea breeze circulations over this site.