Heating and Melting of Floating Ice Shelves

Abstract

Based on an observed temperature profile through the Ross Ice Shelf at Little America and partial profiles in the Maudheim Is-shelf and the Filchner Ice Shelf near the Ellsworth I.G.Y. station, various models of heating with and without melting from below are analysed to find the residence time of the respective ice shelves over the ocean. Estimated movements are compared with observed shelf movements seaward. 100 and 200 yr. melting rates for an ice shelf initially 20.5° C. below the freezing point of seawater are found as functions of the deviation of sea-water from its freezing point and the eddy conductivity of the ocean below the ice shelf. Steady-state solutions based on constant accumulation and sinking in an ice shelf of constant thickness are discussed. The effect of heating of an ice shelf from above and below as it moves to a warmer atmospheric environment is described and it is concluded that the decreasing temperature with depth found only in the Ellsworth ice is a result of its rapid motion from the cold region to the south-east of the station (Coats Land).