Satellite Microwave remote sensing of contrasting surface water inundation changes within the Arctic–Boreal Region

• Published in: Remote sensing of environment Vol. 127; pp. 223 - 236
• Main Authors: Watts, Jennifer D., Kimball, John S., Jones, Lucas A., Schroeder, Ronny, McDonald, Kyle C.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.12.2012; Elsevier
• Subjects: AMSR; Animal, plant and microbial ecology; Applied geophysics; Arctic; Biological and medical sciences; Climate change; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Internal geophysics; Inundation; Landsat; MODIS; Permafrost; Teledetection and vegetation maps; polar regions; Arctic region; Climate change; AMSR; Landsat; Permafrost; Arctic; Inundation; MODIS; atmosphere; microwaves; Earth Observing System; Carbon dioxide; 2010; feedback; dynamics; Daily; Free water; 2003; carbon; flux; soils; climate change; energy; detection; Dynamic characteristic; maps; Space remote sensing; inundations; Landsat satellite; surface water; permafrost; methane; boreal zone; Radiometer
• ISSN: 0034-4257; 1879-0704
• DOI: 10.1016/j.rse.2012.09.003

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. ► We evaluate surface inundation changes in the Arctic–Boreal region from 2003 to 2010. ► AMSR-E passive microwave analysis effectively captures surface water variability. ► Contrasting inundation changes are observed within the major permafrost (PF) zones. ► Continuous PF shows widespread wetting; drying predominates in more degraded PF.