Investigating the Influence of Variable Freshwater Ice Types on Passive and Active Microwave Observations

Remote Sensing

Chris Derksen¹  Peter Toose¹  Claude R. Duguay²  Grant E. Gunn³  David A. Clausi⁴ 

[1] Climate Research Division, Environment and Climate Change Canada, Toronto, ON M3H 5T4, Canada;Department of Geography and Environmental Management, and the Interdisciplinary Centre on Climate Change, University of Waterloo, Waterloo, ON N2L 3G1, Canada;Department of Geography, Environment and Spatial Sciences, Michigan State University, East Lansing, MI 48824, USA;Department of Systems Design Engineering and Vision and Image Processing (VIP) Research Group, University of Waterloo, Waterloo, ON N2L 3G1, Canada;

关键词: active microwave;    passive microwave;    synthetic aperture radar;    lake ice;    ice types;    X-band;    grey ice;    rafted ice;    TerraSAR-X;   

DOI  :  10.3390/rs9121242

来源: DOAJ

【 摘 要 】

Dual-polarized airborne passive microwave (PM) brightness temperatures (Tb) at 6.9 GHz H/V, 19 GHz H/V and 37 GHz H/V and spaceborne active microwave (AM) X-band (9.65 GHz VV, VH) backscatter (σ0) are observed coincident to in situ snow and lake-ice measurements collected over two lakes near Inuvik, Canada. Lake-ice thickness is found to be positively correlated with 19 GHz V emission (R = 0.67) and negatively with 19 GHz H emission (R = −0.79), indicating surface ice conditions influence microwave interaction. Lake ice types are delineated from TerraSAR-X synthetic aperture radar (SAR) images using the iterative region growing with semantics (IRGS) segmentation algorithm implemented in the MAGIC (MAp Guided Ice Classification) system. The spatial extent of derived ice type classes correspond well to in situ observations. The overall magnitude of emission at 19 GHz H and X-band VH σ0 increase with the scattering potential of associated ice types (grey/rafted ice). Transects of 6.9 GHz PM and 19 GHz PM exhibit positive relationships with VH σ0 over freshwater lake ice, with the greatest R coefficients at H-pol (R = 0.64, 0.46). Conversely, 6.9 GHz Tb and 19 GHz Tb exhibit negative R coefficients in regions of brackish water due to tubular bubble and brine inclusions in the ice. This study identifies congruency between PM and AM scattering mechanisms over lake ice for the purpose of identifying the influence of ice types on overall microwave interaction within the lake-ice system.

【 授权许可】

Unknown