West Antarctic Ice Sheet Surface Melting: Recognition Controls and Significance

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This award provides support to study the occurrence of melting in the Ross Embayment of West Antarctica, from a physical and historical perspective, using a combination of techniques (snow-pit, ice-core, AWS, and remotely sensed data, and experiments on melt generation). Surface melting on polar ice sheets occurs as temperatures increase above some threshold. Looking at a variety of records of past surface melting events in Antarctica will reveal changes in the occurrence of especially high temperatures. Joint interpretation of melt and other paleothermometers (borehole temperatures, isotopes, etc.) may allow seasonally resolved paleothermometry. Melting on the surface of an ice sheet can be measured in many ways. Space-based microwave sensors record the occurrence of liquid water or refrozen ice layers in the near surface. Automatic Weather Stations (AWS) record the high temperatures that are linked to development of liquid water. Snow-pit and ice-core studies show layers where refreezing of sufficient liquid water has caused a visibly distinct layer to form. These different measures of melt occurrence are not identical, and are presently not calibrated well to each other. This proposed project will enable the determination of how different measures of melting are related to each other. This knowledge will help glaciologists to learn how melting and climate have changed and affected Antarctic processes in the past, and how they may change in the future. Special focus will be on the critical Ross Ice Shelf and Siple Dome regions of West Antarctica.