THE ANNUAL CYCLE OF THE SURFACE-ENERGY BALANCE OF ANTARCTIC BLUE ICE

A 15-month meteorological data set was obtained from an automatic weat her station over a blue ice area in Dronning Maud Land, Antarctica. Th e meteorological measurements are used as input for a surface energy b alance model in order to compute the hourly varying surface fluxes and the (sub)surface temperatures to a depth of 10 m. The model reproduce s reasonably well the directly measured temperatures in the upper mete r of ice. Model results show that the net shortwave radiation is the l argest positive term in the annual mean energy budget (42.2 W m(-2)). Other positive fluxes are the downward sensible heat flux (12.1 W m(-2 )) and the upward subsurface energy flux (0.2 W m(-2)). Energy is lost by net longwave radiation (-49.1 W m(-2)) and the upward directed lat ent heat flux (-5.0 W m(-2)). We analyze the annual cycle of the surfa ce heat fluxes on the basis of daily, monthly, and seasonally mean val ues. In addition, we calculate the surface energy budget for two disti nctly different weather regimes, which are typical for this region. Fi nally, we demonstrate that the annual cycle of the turbulent fluxes ca n be explained in terms of the limiting values of the Bowen ratio.