Remote Sens. 2012, 4(7), 2133-2155; doi:10.3390/rs4072133
Article

C-Band SAR Imagery for Snow-Cover Monitoring at Treeline, Churchill, Manitoba, Canada

email
Received: 17 May 2012; in revised form: 17 June 2012 / Accepted: 25 June 2012 / Published: 13 July 2012
(This article belongs to the Special Issue Remote Sensing by Synthetic Aperture Radar Technology)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: RADARSAT and ERS-2 data collected at multiple incidence angles are used to characterize the seasonal variations in the backscatter of snow-covered landscapes in the northern Hudson Bay Lowlands during the winters of 1997/98 and 1998/99. The study evaluates the usefulness of C-band SAR systems for retrieving the snow water equivalent under dry snow conditions in the forest–tundra ecotone. The backscatter values are compared against ground measurements at six sampling sites, which are taken to be representative of the land-cover types found in the region. The contribution of dry snow to the radar return is evident when frost penetrates the first 20 cm of soil. Only then does the backscatter respond positively to changes in snow water equivalent, at least in the open and forested areas near the coast, where 1-dB increases in backscatter for each approximate 5–10 mm of accumulated water equivalent are observed at 20–31° incidence angles. Further inland, the backscatter shows either no change or a negative change with snow accumulation, which suggests that the radar signal there is dominated by ground surface scattering (e.g., fen) when not attenuated by vegetation (e.g., forested and transition). With high-frequency ground-penetrating radar, we demonstrate the presence of a 10–20-cm layer of black ice underneath the snow cover, which causes the reduced radar returns (−15 dB and less) observed in the inland fen. A correlation between the backscattering and the snow water equivalent cannot be determined due to insufficient observations at similar incidence angles. To establish a relationship between the snow water equivalent and the backscatter, only images acquired with similar incidence angles should be used, and they must be corrected for both vegetation and ground effects.
Keywords: remote sensing; snow; SAR; C-band backscatter; RADARSAT; ERS; ground penetrating radar; treeline; forest-tundra ecotone
PDF Full-text Download PDF Full-Text [1620 KB, uploaded 19 June 2014 00:31 CEST]

Export to BibTeX |
EndNote


MDPI and ACS Style

Pivot, F.C. C-Band SAR Imagery for Snow-Cover Monitoring at Treeline, Churchill, Manitoba, Canada. Remote Sens. 2012, 4, 2133-2155.

AMA Style

Pivot FC. C-Band SAR Imagery for Snow-Cover Monitoring at Treeline, Churchill, Manitoba, Canada. Remote Sensing. 2012; 4(7):2133-2155.

Chicago/Turabian Style

Pivot, Frédérique C. 2012. "C-Band SAR Imagery for Snow-Cover Monitoring at Treeline, Churchill, Manitoba, Canada." Remote Sens. 4, no. 7: 2133-2155.

Remote Sens. EISSN 2072-4292 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert