Ice Freeze-up and Break-up Detection of Shallow Lakes in Northern Alaska with Spaceborne SAR

Remote Sensing

Cristina M. Surdu⁴  Claude R. Duguay¹  Homa Kheyrollah Pour¹  Laura C. Brown³  Richard Gloaguen² 

[1] Department of Geography and Environmental Management, and Interdisciplinary Centre on Climate Change, University of Waterloo, Waterloo, ON N2L 3G1, Canada; E-Mails:;id="af1-remotesensing-07-06133">1Earth Observation/Science, Applications and Future Technologies Department, European Space Agency (ESA), 00044 Frascati, Ita;Department of Geography, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; E-Mail:;Earth Observation/Science, Applications and Future Technologies Department, European Space Agency (ESA), 00044 Frascati, Italy

关键词: Arctic lakes;    break-up;    freeze onset;    synthetic aperture radar;   

DOI  :  10.3390/rs70506133

来源: mdpi

【 摘 要 】

Shallow lakes, with depths less than ca. 3.5–4 m, are a ubiquitous feature of the Arctic Alaskan Coastal Plain, covering up to 40% of the land surface. With such an extended areal coverage, lakes and their ice regimes represent an important component of the cryosphere. The duration of the ice season has major implications for the regional and local climate, as well as for the physical and biogeochemical processes of the lakes. With day and night observations in all weather conditions, synthetic aperture radar (SAR) sensors provide year-round acquisitions. Monitoring the evolution of radar backscatter (σ°) is useful for detecting the timing of the beginning and end of the ice season. Analysis of the temporal evolution of C-band σ° from Advanced Synthetic Aperture Radar (ASAR) Wide Swath and RADARSAT-2 ScanSAR, with a combined frequency of acquisitions from two to five days, was employed to evaluate the potential of SAR to detect the timing of key lake-ice events. SAR observations from 2005 to 2011 were compared to outputs of the Canadian Lake Ice Model (CLIMo). Model simulations fall within similar ranges with those of the SAR observations, with a mean difference between SAR observations and model simulations of only one day for water-clear-of-ice (WCI) from 2006 to 2010. For freeze onset (FO), larger mean differences were observed. SAR analysis shows that the mean FO date for these shallow coastal lakes is 30 September and the mean WCI date is 5 July. Results reveal that greater variability existed in the mean FO date (up to 26 days) than in that of melt onset (MO) (up to 12 days) and in that of WCI (6 days). Additionally, this study also identifies limitations and provides recommendations for future work using C-band SAR for monitoring the Lake-ice phenology of shallow Arctic lakes.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.