The Impact of the Snow Pack on the Atmospheric Boundary Layer: Some Results from GABLS4 and a General Circulation Model

Over the past decade, the GABLS project has provided a focus for efforts to improve the representation of stable boundary layers in atmospheric models. During that time, the important role played by the underlying surface has been increasingly recognized. The current project, GABLS4, is concerned with the simulation of the boundary layer over snow and is based on observations from the Antarctic Plateau.

A multilayer snow scheme has recently been implemented in the configuration of the Met Office Unified Model that will be used for future climate and forecasting applications. The inclusion of this scheme has resulted in substantial improvements in the simulation of near-surface air temperature. Results from the general circulation model will be used to emphasize the importance of the thermal response of the snow pack in yielding good forecast performance for near-surface weather.

GABLS4 provides an excellent framework for testing interactions between the snow surface and the atmospheric boundary layer. Results from simulations for GABLS4 using this snow scheme will be presented and sensitivity studies suggesting areas for further improvements to the simulation of the boundary layer over snow will be discussed.