Opposite Trends of Wind-Associated Melt in Greenland and Antarctica
Antarctic wind-associated melt has decreased by about ~32% since 1999, while total melt has decreased by about 15% due to reduced föhn-induced melt on the Antarctic Peninsula and increased stratospheric ozone. Wind-associated melt has increased by about 10% in Greenland, combined with warmer surface temperatures to increase total melt on Greenland by about 34% since the mid-1990s.
Ice sheet surface melt processes that drive sea-level rise are complex, interlinked, and non-intuitive. Replicating our findings is an important challenge for the physical fidelity of Earth System Models such as E3SM.
Föhn and katabatic winds (winds that travel downslope) can increase ice sheet surface melt which increases sea levels and ice-shelf vulnerability. We use regional climate model simulations of the Greenland and Antarctic ice sheets (GIS and AIS) to identify trends in downslope winds and associated melt. Results reveal surface melt associated with downslope winds is significant on both the GIS and AIS, representing 27.5% and 19.7% of total surface melt respectively. Wind-associated melt has decreased 31.8% since 1999 on the AIS while total melt has decreased 15.4 ± 2.4% due to decreased föhn-induced melt on the Antarctic Peninsula and increasing stratospheric ozone that decreases sunlight at the surface. Wind-associated melt has increased by 10.3% on the GIS, combined with warmer surface temperatures to increase total melt by 34%. Replicating our findings is an important challenge for the physical fidelity of Earth System Models such as E3SM.