Some Atmospheric Surface Layer Characteristics over Varanasi from MONTBLEX-90

An attempt has been made to study the atmospheric surface layer characteristics such as Richardson number (Ri). Monin-Obukhov length scale (L), friction velocity (U* ), friction temperature (u*), roughness length (Z0), turbulent kinetic energy (TKE), ratio of eddy conductivity to eddy diffusivity (Km :Kh ) over a semi-moist convective regime. Data which were collected at Varanasi (25°18%N, 83°E) as part of the experiment known as MONTBLEX-90 (Monsoon Trough Boundary Layer Experiment) during the summer monsoon season was used in the present study. The variation of the above parameters with stability has been discussed. The differences within the surface layer are also pointed out. Some broad features are found to coincide with that of BUSINGER et al. (1971). The heterogeneity and the anisotropic turbulence typical of monsoon tropical atmosphere are shown to be responsible for the deviations noticed within the surface layer.