Coupling and decoupling processes in monsoonal surface layer using MONTBLEX-90 tower data

Abstract

ABSTRACT. MONI'BLEX-90 data of Varanasi and Jodhpur have been used to study the physical processes in the surface layer. The results show that turbulent transfer of heat, momentum and moisture commence at an average eddy viscosity of an order of magnitude 5.13 × 10^-1 J ^-s kg^-1 during rainy day. In absolutely stable case, eddy viscosity may be equal to 4.94 × 10^-4 J^-s kg^-1 or less to decouple surface layer from rest of the planetary boundary layer for extinction of the turbulent transfer of fluxes. These results were based on 8m and 15m meteorological tower observations and surface soil temperature using analytical solution of Byun (1990) and K theory. It was found that the surface layer is decoupled only in case of stability of Class - A because bulk Richardson number is greater than zero and corresponding stability parameter is positive.