Name
Evaluation of optical and radar snow disappearance estimates in a forested watershed using Airborne Laser Scanning
Date & Time
Tuesday, May 26, 2026, 2:45 PM - 3:00 PM
Description
Accurate snow cover mapping is fundamental to mountain research; however, remotely sensed snow-covered area (SCA) estimates are often unavailable at high temporal and spatial resolutions (< 30 m) and require further validation in forests. Here, we evaluate optical and radar remote sensing approaches for SCA estimation using snow cover maps derived from Airborne Laser Scanning (ALS) in a forested watershed on Vancouver Island, British Columbia. We tested five snow disappearance algorithms applied to observations from the Harmonized Landsat Sentinel collection and Sentinel-1. We included two SAR-primary approaches (the Buchelt et al. [2022] approach and a new method); two optical approaches (both using Normalized Difference Snow Index [NDSI] estimates, but differing in cloud treatment); and one hybrid approach (which constrained NDSI estimates of snow disappearance with SAR estimates of snowmelt onset). We converted snow disappearance estimates to binary SCA maps and evaluated against ALS data for five acquisition dates between March and June in 2020, 2021, and 2023. The most accurate approach was the optical-SAR approach (overall accuracy 84%, F1 = 0.86), which also produced the most reliable estimates of basin SCA (RMSE = 27 km2, basin area = 215 km2). The optical and novel SAR approaches achieved overall accuracies of 81%. While all approaches were less accurate under forest cover, the optical-SAR algorithm minimized this difference, with average accuracies of 88% in open areas and 83% in forested areas. The optical–SAR algorithm for snow disappearance provides a robust, low-cost approach for snow cover estimation in complex, forested terrain.
Location Name
McInnes Room
Full Address
Dalhousie University
Halifax NS
Canada
Session Type
Oral Presentation
Abstract ID
331
Speaker Organization
University of Northern British Columbia
Session Name
H9 (2 of 2)
Co-authors
Joseph Shea Geography, Earth, and Environmental Sciences, University of Northern British Columbia, Prince George, BC Rosie Bisset Geography, Earth, and Environmental Sciences, University of Northern British Columbia, Prince George, BC Vancouver Island University, Coastal Hydrology Research Laboratory, Nanaimo, BC Bill Floyd Geography, Earth, and Environmental Sciences, University of Northern British Columbia, Prince George, BC Vancouver Island University, Coastal Hydrology Research Laboratory, Nanaimo, BC British Columbia Ministry of Forests, Nanaimo, BC Brian Menounos Geography, Earth, and Environmental Sciences, University of Northern British Columbia, Prince George, BC Hakai Institute, Campbell River, BC Geological Survey of Canada Pacific, Natural Resources Canada, Sidney, BC
Presenting Author
Sara Darychuk, University of Northern British Columbia, Department of Geography, Earth, and Environmental Sciences