Topographic control of snow distribution in an alpine watershed of western Canada inferred from spatially-filtered MODIS snow products

• Published in: Hydrology and earth system sciences 2009-03, Vol.13 (3), p.319-326
• Main Authors: Tong, J, Déry, S.J, Jackson, P.L
• Format: Article
• Language: English
• Subjects: clouds; mountains; remote sensing; snow; snowpack; spatial filters; topography; watershed hydrology; watersheds
• ISSN: 1027-5606; 1607-7938; 1607-7938
• DOI: 10.5194/hess-13-319-2009

A spatial filter (SF) is used to reduce cloud coverage in Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day maximum snow cover extent products (MOD10A2) from 2000–2007, which are obtained from MODIS daily snow cover extent products (MOD10A1), to assess the topographic control on snow cover fraction (SCF) and snow cover duration (SCD) in the Quesnel River Basin (QRB) of British Columbia, Canada. Results show that the SF reduces cloud coverage and improves by 2% the accuracy of snow mapping in the QRB. The new product developed using the SF method shows larger SCF and longer SCD than MOD10A2, with higher altitudes experiencing longer snow cover and perennial snow above 2500 m. The gradient of SCF with elevation (d(SCF)/dz) during the snowmelt season is 8% (100 m)−1. The average ablation rates of SCF are similar for different 100 m elevation bands at about 5.5% (8 days)−1 for altitudes 2500 m. Different combinations of slopes and aspects also affect the SCF with a maximum difference of 20.9% at a given time. Correlation coefficients between SCD and elevation attain 0.96 (p