G. D. Tallentire *1, J. Evans 1 & R. Hodgkins 1
1 Geography and Environment, Loughborough University, Epinal Way, Loughborough, LE11 3TU, UK. *G.D.Tallentire@lboro.ac.uk
Sediment plumes can be identified in Arctic fjords and oceans from space for a limited period of time during the summer months. They are formed by the mixing of very fine glacial sediments and meltwater which is released from glaciers and ice caps during melt. Sediment plumes are useful for determining the contribution of meltwater reaching fjords and oceans across the Arctic region, and can also be used in calculations of global sea-level rise. More recently they have been used as analogues, because direct measurements of ice-melt in the Arctic are difficult to ascertain as conditions are harsh for long periods of the year, and equipment is both expensive to maintain and easily damaged by the extreme climate. Here we show how enhancements in satellite imagery can be used to improve our understanding of sediment plumes as an alternative to routine direct measurements, and give greater insights into climate change in the Norwegian high Arctic. Using images of superior quality we can better understand how sediment plumes change during a melt season and over a number of years, including calculating dimensions e.g. length and width, and also the amount of sediment per litre of water and thickness of the plume using measurements collected in-person (Figure 1). Our aim is for future sediment plume studies to place less reliance on field measurements and make use of the large volumes of satellite data that is now freely available.
Figure 1. A PlanetScope satellite image (3x3 metres) captured on the 27/07/2019 of Kongsfjorden, Svalbard showing land-terminating glaciers on Brøggerhalvøya to the south, and Blomstrandbreen a marine-terminating glacier to the north. The red stars show areas where in-person measurements were collected. At the edges of the fjord note the different colours on the surface of the water, these are known as sediment plumes and occur either when a river flows directly into the ocean, or at marine-terminating glacier-fronts where sediment-rich water is forced to the surface from beneath the glacier.
References
Planet Team. 2020. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/