Study of micrometeorological characteristics of the atmospheric surface layer over a tropical coastal station in Goa

Abstract

This study presents turbulence characteristics of the atmospheric surface layer (ASL) observed during March 2015 to February 2016 over a tropical coastal site in Goa (15.46 degrees N, 73.83 degrees E), India. The primary datasets utilized are the 3D wind components and sonic temperature from sensors mounted on a 32-m meteorological tower at 10 and 20 m heights respectively. Eddy correlation technique has been adopted to study turbulence characteristics and is investigated under the framework of Monin-Obukhov Similarity Theory (MOST). Results revealed that normalized wind variances (Sigma sub(i=u,v,w)/u sub(*)) follow the '1/3' power law in highly unstable and stable conditions and approach constant values close to near-neutral conditions. In the neutral limit, it is found that Sigma sub(u)/u sub(*) greater than Sigma sub(v)/u sub(*) greater than Sigma sub(w)/u sub(*). The normalized temperature variances (Sigma sub(T)/T sub(*)) followed (z/L) sup(-1/3) during unstable conditions and approach a constant value in the stable limit. The correlation coefficients for momentum (heat) flux with stability were small (high) under strong unstable and stable conditions. Also, the values of momentum flux increased as it approaches neutral conditions which are consistent with studies reported over coastal/urban locations.