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Abstract

In recent decades, the Ross Ice Shelf (RIS) has experienced frequent summer surface melting, which accelerates ice loss and increases the instability of ice sheets. This study investigates the remote forcing and local air-ice interaction responsible for the surface melting process. The northerly wind anomaly over RIS is established as part of a quasi-geostrophic barotropic Rossby wave train from subtropical Australia toward West Antarctica. After the northern wind anomaly is established, the response of the surface energy budget to the warm and moist air intrusion is discussed. By applying Climate Feedback-Response Analysis Method (CFRAM), the temporal surge of the downward longwave (LW) surface radiative fluxes over the Ross Ice Shelf (RIS) and adjacent regions during four historically massive RIS surface melting events are decomposed to identify the main contributor. It is found that the intrusion of warm and humid air flows from lower latitudes conduces to warm air temperature and more water vapor anomalies, as well as cloud development. These changes make a cooperative impact on the abnormal enhancement of the downward LW surface radiative fluxes, contributing significantly the surface warming and causing massive ice melting.