Formulation and testing of a climatonomic simulation of the microclimate of the dry valleys and of the little America v station in Antarctica

Abstract

A climatonomy model to synthesize monthly-mean energy fluxes and temperatures for a snow-covered and snow-free surface in the Antarctic is described. The system is composed of two submodels based on simple, bulk parameterization of physical processes. The first describes the scattering and absorption of global radiation by the atmosphere, while the second partitions the surface fluxes at the ground and predicts their time-series values over the annual cycle.

The submodels are calibrated from measurements at Little America V on a snow surface and at Vanda Station in the dry valleys. Resulting parameterization is tested at a third location (Little America III). Synthetic fluxes and temperatures agree well with measurements and reproduce not only the seasonal trends, but also short-term month-to-month variations.

Sensitivity tests illustrate the importance of advection as well as surface albedo at the two sites. The relative response of temperatures and energy fluxes is shown to depend on the duration and magnitude of the input perturbations, as well as on the local climate. Such responses are not always intuitively predictable. Thus, while the surface variables, especially the albedo, must play a key role in maintaining the snowless character of the Antarctic oases, the importance of advection should be tested in a model which realistically provides feedback with the surrounding snow-covered terrain.