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Abstract:
In the 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 links the interannual variability of surface melting events over the RIS with the northerly wind anomaly over the Ross Sea sector, which is established in association with a quasi-geostrophic barotropic Rossby wave train from subtropical Australia toward West Antarctica. The Rossby wave train is regulated jointly by El Niño and atmospheric heating over western Australia. El Niño provides the major forcing of the atmospheric circulation anomalies over the Ross Sea, and most surface melting events over the RIS happened during El Niño years. In addition, the anomalous atmospheric heating over western Australia is identified as the other significant forcing that triggers the Rossby wave train. The northerly flow is sandwiched between the low and high geopotential height anomalies located respectively over the left-hand and right-hand sides of the Ross Sea, favoring strong poleward moisture and heat transport and leading to surface melting over the RIS.
