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- Title
Arctic‐Boreal Lake Dynamics Revealed Using CubeSat Imagery.
- Authors
Cooley, Sarah W.; Ryan, Jonathan C.; Smith, Laurence C.; Pitcher, Lincoln H.; Pavelsky, Tamlin M.
- Abstract
Fine‐scale, subseasonal fluctuations in Arctic‐Boreal surface water reflect regional water balance and modulate trace gas emissions to the atmosphere but have eluded detection using traditional satellite remote sensing. We use high‐resolution (~3–5 m), high‐frequency CubeSat sensors to measure near‐daily changes in lake surface area through an object‐based tracking method that incorporates machine learning to overcome notable limitations of CubeSat imagery. From ~76,000 images we obtain >2.2 million individual observations of changing surface areas for 85,358 lakes in Northern Canada and Alaska between 1 May and 1 October 2017. We find broad‐scale lake area declines across diverse climatic, hydrologic, and physiographic terrains. Localized exceptions reveal lowland flooding and aquatic vegetation phenology cycles. Cumulative small shoreline changes of abundant lakes on the Canadian Shield exceed total inundation variations of better‐studied lowland environments, revealing a surprisingly dynamic landscape with respect to subseasonal variations in surface water extent and trace gas emissions. Plain Language Summary: Fluctuations in Arctic‐Boreal lakes reflect climate change and regulate freshwater methane and CO2 emissions. Observing these fine‐scale changes has traditionally been difficult due to the coarse spatial and temporal resolution of available satellite imagery. Recently, however, the launch of hundreds of tiny satellites known as CubeSats has created new opportunities for monitoring lake area through providing daily imagery at 3‐m resolution. Here we present a new method for tracking lake area changes using CubeSat imagery, which overcomes limitations that have, until now, prevented large‐scale CubeSat analyses. Using this method, we track changes in lake area for ~85,000 lakes across Northern Canada and Alaska between May and October 2017. We observe a general seasonal decline in lake area across diverse terrains but identify localized exceptions caused by wetland flooding and the growth and decline of vegetation on the lake surface. Surprisingly, the greatest absolute lake area changes occur in upland, lake‐dense terrains previously thought to be very stable. In these regions, small (<10 m) changes along lake margins cumulatively sum to large changes in total lake area that are largely undetectable from coarser‐resolution satellites. This previously unquantified lake area variability suggests that models may underestimate greenhouse gas emissions in these regions. Key Points: We use CubeSat satellite imagery and machine learning to track sub‐seasonal changes in surface water area for 85,358 Arctic‐Boreal lakesWe observe a broad‐scale seasonal decline in lake area dominated by small (<10 m), previously unquantified, lake shoreline contractionsThe sum of these contractions reveals that lake‐dense areas experience substantial water loss with implications for trace‐gas emissions
- Subjects
CUBESATS (Artificial satellites); WATER; WATER balance (Hydrology); TRACE gases; REMOTE sensing
- Publication
Geophysical Research Letters, 2019, Vol 46, Issue 4, p2111
- ISSN
0094-8276
- Publication type
Article
- DOI
10.1029/2018GL081584