Satellite Microwave remote sensing of contrasting surface water inundation changes within the Arctic-Boreal Region
Remote Sensing of Environment
Surface water inundation in the Arctic–Boreal region is dynamic and strongly influences land-atmosphere water, energy and carbon (CO2, CH4) fluxes, and potential feedbacks to climate change. Here we report on recent (2003–2010) surface inundation patterns across the Arctic–Boreal region (≥ 50°N) and within major permafrost (PF) zones detected using satellite passive microwave remote sensing retrievals of daily fractional open water (Fw) cover from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E). The AMSR-E Fw (25-km resolution) maps reflect strong microwave sensitivity to sub-grid scale open water variability and compare favorably (0.71 ≤ R2 ≤ 0.84) with alternative, static Fw maps derived from finer scale (30-m to 250-m resolution) Landsat, MODIS and SRTM radar (MOD44W) data. The AMSR-E retrievals show dynamic seasonal and annual variability in surface inundation that is unresolved in the static Fw maps. The AMSR-E Fw record also corresponds strongly (0.71 ≤ R ≤ 0.87) with regional wet/dry cycles inferred from basin discharge records. An AMSR-E algorithm sensitivity analysis shows a conservative estimate of Fw retrieval uncertainty (RMSE) within ± 4.1% for effective resolution of regional inundation patterns and seasonal to annual variability. A regional trend analysis of the 8-year AMSR-E record shows no significant Arctic–Boreal region wide Fw trend for the period, and instead reveals contrasting inundation changes within different PF zones. Widespread Fw wetting is detected within continuous (92% of grid cells with significant trend; p < 0.1) and discontinuous (82%) PF zones, while sporadic/isolated PF areas show widespread (71%) Fw drying trends. These results are consistent with previous studies showing evidence of contrasting regional inundation patterns linked to PF degradation and associated changes to surface hydrology under recent climate warming.
AMSR, Arctic, climate change, Inundation, Landsat, MODIS, Permafrost
© 2012 Elsevier
Jennifer D. Watts, John S. Kimball, Lucas A. Jones, Ronny Schroeder, Kyle C. McDonald, Satellite Microwave remote sensing of contrasting surface water inundation changes within the Arctic–Boreal Region, Remote Sensing of Environment, Volume 127, December 2012, Pages 223-236, http://dx.doi.org/10.1016/j.rse.2012.09.003