Arctic-Boreal Lake Phenology Shows a Relationship between Earlier Lake Ice-Out and Later Green-Up

Remote Sensing

Aji John¹  Janneke Hille Ris Lambers²  David Butman³  Catherine Kuhn³  Amanda Tan⁴ 

[1] Department of Biology, University of Washington, Seattle, WA 98195, USA;Department of Environmental Systems Science, ETH Zürich, 8092 Zurich, Switzerland;School of Forestry & Environmental Science, University of Washington, Seattle, WA 98195, USA;eScience Institute, University of Washington, Seattle, WA 98195, USA;

关键词: arctic;    boreal;    lake;    phenology;    PlanetScope;    Sentinel-2;   

DOI  :  10.3390/rs13132533

来源: DOAJ

【 摘 要 】

Satellite remote sensing has transformed our understanding of Earth processes. One component of the Earth system where large uncertainties remain are Arctic and boreal freshwater lakes. With only short periods of open water due to annual ice cover, lake productivity in these regions is extremely sensitive to warming induced changes in ice cover. At the same time, productivity dynamics in these lakes vary enormously, even over short distances, making it difficult to understand these potential changes. A major impediment to an improved understanding of lake dynamics has been sparsely distributed field measurements, in large part due to the complexity and expense of conducting scientific research in remote northern latitudes. This project overcomes that hurdle by using a new set of ‘eyes in the sky’, the Planet Labs CubeSat fleet, to observe 35 lakes across 3 different arctic-boreal ecoregions in western North America. We extract time series of lake reflectance to identify ice-out and green-up across three years (2017–2019). We find that lakes with later ice-out have significantly faster green-ups. Our results also show ice-out varies latitudinally by 38 days from south to north, but only varies across years by ~9 days. In contrast, green-up varied between years by 22 days in addition to showing significant spatial variability. We compare PlanetScope to Sentinel-2 data and independently validate our ice-out estimates, finding an ice-out mean absolute difference (MAD) ~9 days. This study demonstrates the potential of using CubeSat imagery to monitor the timing and magnitude of ice-off and green-up at high spatiotemporal resolution.

【 授权许可】

Unknown