Airborne Measurements in the Stable Boundary Layer over the Larsen Ice Shelf, Antarctica

摘要

We present aircraft measurements of boundary-layer structure and surface turbulent fluxes from a flight over the Larsen Ice Shelf, Antarctica. Warm advection, associated with fcehn flow, led to the formation of a stable boundary layer over the ice shelf, with a well-defined low-level jet at the top of the surface inversion. The strong shear associated with the jet kept the gradient Richardson number small and maintained a turbulent boundary layer over a depth of at least 600 m. The net surface energy balance amounted to 52 Wmpo, equivalent to a melt rate of 13 mm water per day, with net radiation (48 Wmpo) making the largest contribution to melt. The contribution from the sensible heat flux (13 Wmpo) was largely balanced by an upwards latent heat flux (-9 Wmpo). These measurements provide insight into the processes that control surface melt rates in an area that has experienced recent rapid warming and deglaciation.