Publications

Snow, T; Zhang, W; Schreiber, E; Siegfried, M; Abdalati, W; Scambos, T (2023). Alongshore Winds Force Warm Atlantic Water Toward Helheim Glacier in Southeast Greenland. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 128(9), e2023JC019953.

Abstract
Enhanced transport of warm subsurface Atlantic Water (AW) into Greenland fjords has driven glacier mass loss, but the mechanisms transporting AW to the fjords remain poorly characterized. Here, we provide the first direct satellite-based observations of rapid (& SIM;0.2 m/s) AW intrusion toward Sermilik Fjord abutting Helheim Glacier, one of Greenland's largest glaciers. The intrusions arise when coastal upwelling-through interactions with Sermilik's bathymetric trough on the continental shelf-triggers enhanced AW upwelling and inflow that can travel tens of kilometers along the trough within hours. A weakening or reversal of northeasterly alongshore winds stimulates the intrusions and is often associated with the passing of cyclones and subsequent sea surface lowering. Mooring data show that these intrusions produce subsurface ocean warming both at Sermilik Fjord mouth and within the fjord and that the warming signal in the fjord does not diminish during subsequent coastal downwelling events. Satellite imagery captures near-synchronous AW intrusions at multiple troughs rimming southeast Greenland suggesting that these wind-driven processes may play a substantial role in ocean heat transport toward the Greenland Ice Sheet. Greater transport of the warm subtropical Atlantic Waters into Greenland fjords has driven glacier mass loss, but the mechanisms transporting the subtropical waters to glacier fronts remain poorly characterized. Here, we provide the first satellite-based observations of rapid flow of subtropical water toward Sermilik Fjord abutting Helheim Glacier, one of Greenland's largest glaciers. Often associated with the passing of cyclones, strong alongshore wind events stimulate ocean circulation that brings subtropical waters from offshore onto the continental shelf along an underwater trough that leads to Helheim. Our measurements show that when these events produce ocean warming nearshore, they tend to transport more heat toward Helheim Glacier's front where it may increase ice melting. A higher number of such wind events in a season has the potential to impact glacier calving, thinning, and retreat. Satellite imagery shows that these events can occur simultaneously along other bathymetric troughs leading toward other Greenland glaciers in the southeast and potentially elsewhere. Therefore, these ocean events may be important for predicting future Greenland Ice Sheet ice loss. Alongshore wind-driven coastal upwelling drives Atlantic Water intrusions onto the continental shelf along Sermilik TroughThis work represents the first remote-sensing evidence of intrusion events along a bathymetric depressionRapid intrusions often transport warm subsurface water to the inner shelf and fjord in less than 1 day

DOI:
10.1029/2023JC019953

ISSN:
2169-9291