MODIS observed increase in duration and spatial extent of sediment plumes in Greenland fjords

• Published in: The Cryosphere
• Main Authors: B. Hudson, I. Overeem, D. McGrath, J. P. M. Syvitski, A. Mikkelsen, B. Hasholt
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2014
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; Greenland; Ice Sheet; North Atlantic; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-8-1161-2014; https://doaj.org/article/4817beddb4634eb592df760103bdbf89

The freshwater flux from the Greenland Ice Sheet (GrIS) to the North Atlantic Ocean carries extensive but poorly documented volumes of sediment. We develop a suspended sediment concentration (SSC) retrieval algorithm using a large Greenland specific in situ data set. This algorithm is applied to all cloud-free NASA Moderate Resolution Imaging Spectrometer (MODIS) Terra images from 2000 to 2012 to monitor SSC dynamics at six river plumes in three fjords in southwest Greenland. Melt-season mean plume SSC increased at all but one site, although these trends were primarily not statistically significant. Zones of sediment concentration > 50 mg L −1 expanded in three river plumes, with potential consequences for biological productivity. The high SSC cores of sediment plumes ( > 250 mg L −1 expanded in one-third of study locations. At a regional scale, higher volumes of runoff were associated with higher melt-season mean plume SSC values, but this relationship did not hold for individual rivers. High spatial variability between proximal plumes highlights the complex processes operating in Greenland's glacio–fluvial–fjord systems.