SHEBA flux-profile relationships in the stable atmospheric boundary layer

摘要

Measurements of atmospheric turbulence made during the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) are used to examine the profile stability functions of momentum, phi_m, and sensible heat, phi_h, in the stably stratified boundary layerover the Arctic pack ice. Turbulent fluxes and mean meteorological data that cover different surface conditions and a wide range of stability conditions were continuously measured and reported hourly at five levels on a 20-m main tower for 11 months. The comprehensive dataset collected during SHEBA allows studying phi_m and phi_h in detail and includes ample data, for the very stable case. New parameter-izations for phi_m(zeta) and phi_h(zeta) in stable conditions are proposed to describe the SHEBA data; these cover the entire range of the stability parameter zeta = z/L from neutral to very stable conditions, where L is the Obukhov length and z is the measurement height. In the limit of very strong stability, phi_m follows a zeta~(1/3) dependence, whereas ph_h initially increases with increasing zeta, reaches a maximum at zeta approx 10, and then tends to level off with increasing zeta. The effects of self-correlation, which occur in plots of phi_m and phi_h versus zeta, are reduced by using an independent bin-averaging method instead of conventional averaging.