Seasonal hydrography of Ameralik: a southwest Greenland fjord impacted by a land‐terminating glacier

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Stuart-Lee, A.E., Mortensen, J., van der Kaaden, A.-S., Meire, L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Ameralik; Greenland; glacier; Godthåbsfjord
• Online Access: https://www.vliz.be/imisdocs/publications/28/370028.pdf

Greenland’s coastal zone encompasses a large number of fjords, many of which are impacted by glacial meltwater runoff from land-terminating glaciers. This type of fjord has received limited research attention, yet may represent the future of other fjords currently impacted by marine-terminating glaciers that are retreating. In this study we describe the seasonal hydrography of Ameralik, a fjord on the southwest coast of Greenland impacted by a land-terminating glacier. To complement this analysis we compare our results with observations from the neighbouring Godthåbsfjord, which receives meltwater from both land- and marine-terminating glaciers. We find that the absence of subglacial discharge and glacial ice in Ameralik has a strong impact on the inner fjord density profiles and on circulation. The mean temperature of the upper 50 m layer was lower in Ameralik than Godthåbsfjord in May, but by September was 2 ◦ C higher in Ameralik. Dense coastal inflows occur in the late winter months in Ameralik, flushing the fjord and contributing to the return to a weakly stratified state. During the runoff period the surface waters are subject to estuarine circulation and wind forcing, while at intermediate depths a density gradient between the inner and outer fjord regions produces an intermediate baroclinic circulation, resulting in the exchange of water in this layer and the deepening of isopycnals. During summer a large fraction of the meltwater runoff is retained within the fjord rather than being exported. A substantial export of this summer accumulated freshwater occurs in connection with coastal inflows during winter.