Observations of the Dynamics and Kinematics of the Atmospheric Surface Layer on the Ross Ice Shelf, Antarctica

Abstract

Row Island, Antarctica with its 3000 m volcanic peaks a prodigious barrier to the predominant southerly airflow of the western Ross Ice Shelf, Antarctica. This study investigates the relationship of Ross Island to the dynamics and kinematics of the atmosphere using surface data from an army of six automatic weather stations on the Ross Ice Shelf just south of Ross Island. After the actual horizontal pressure gradients had been determined, dynamical relations were obtained which confirmed previous related research. The values of geostrophic departure angle found in this study are in good agreement with the findings of other researchers. Furthermore, a previously determined tendency of the geostrophic departure angle to increase with increasing wind speed over open ice has been confirmed in the region far to the south of the influence of Ross Island. Near the south side of Ross Island, however, this relation does not apply. It is postulated that the forcing of Ross Island on the dynamics of the lowest layers of the atmosphere is causing this difference to occur. Through an analysis of the individual terms in the equation of motion, further support was found for this hypothesis. On the assumption of a linear decrease of friction with height, the height for zero friction increases towards the south of Ross Island. Finally, tentative evidence of higher pressure immediately to the south of the island has been found, which further supports the theory that the cold stable air advected northward by the predominant southerly flow is piling up on the south side of Ross Island.