Blog Archive

Thursday, February 19, 2009

Guido Grosse: Monitoring thaw lake dynamics using high-resolution remote sensing (thermokarst lakes, melting permafrost, methane in Siberia & Alaska)

Monitoring thaw lake dynamics using high-resolution remote sensing

Examples from the Cape Espenberg area (Seward Peninsula) and the Kolyma lowland (Siberia)

Guido Grosse

in collaboration with Katey Walter, Lawrence Plug, Vladimir Romanovsky, Mary Edwards, Lee Slater, Meghan Tillapaugh and Melanie Engram

Summary of First Results

Seward Peninsula

- All lakes visually inspected show signs of rapid expansion up to 1 m/yr

- Extensive permafrost collapse areas on lake margins are camouflaged by floating
vegetation mats (FVM); collapse zones expand with more than 1 m/yr

- Low shorelines towards old basins appear to erode more rapid than high bluffs ! impact of
ice content and sediment volume that has to be removed

- Some considerably large lakes drained partially or completely

- Very few new lakes formed

- Direct impact of long-term precipitation fluctuations on water level appears to be negligible
compared to thermokarst and erosion dynamics; however, short-term precipitation events
might be a cause for activating or speeding up both erosion and drainage processes

Kolyma Lowland

- Only lakes in Yedoma deposits around Cherskii were assessed so far

- Human disturbance results in massive thermokarst

- Erosion rates are similar to Seward Peninsula


• A wide range of high-resolution remote sensing platforms are available today for Arctic Research

• Remote sensing is highly valuable to assess the spatial dimensions of environmental change in the Arctic

• Using remote sensing we can cover 42 years of land surface changes in the Kolyma lowland and 56 years on the Seward Peninsula

• Thermokarst is highly dynamic and active today in Siberia and Alaska – probably we will see surprising results and feedbacks in the coming years

• Thermokarst lakes behave nonlinear in their spatial dynamics; driven by cryolithological ground conditions and external forcing, slow lake forming processes are accompanied by phases of rapid expansion or sudden drainage

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