Effects of surface heterogeneity on the atmospheric boundary layer in Arctic region

The present work is focused on studying the effects of structural and thermal non-uniformity at the ice covered surface on the ABL structure and the surface fluxes. Calculation of turbulent fluxes in the confined area with irregular underlying surface requires careful selection of method of calculation and type of parameterization of coefficients. Exchange coefficients, calculated by direct measurements of turbulent fluxes do not correlate with any single meteorological parameter, but rather depend on an ensemble of factors, which are usually difficult to estimate. Profile method of turbulent flux calculation provides results, which coincide with direct measurements only under the conditions when Monin-Obukhov theory is valid. We present the results of the following studies: (a) heat exchange over leads and polynyas, as well as puddles area, (b) ABL over the margin ice zone, (c) ABL over the hummock surface. Transformation of air flow caused by change of the surface type is also considered. We select the parameterization method for surface turbulence fluxes on the basis of the scale of the surface heterogeneity and ABL stratification. The results of calculations are compared with experimental data.