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Titel |
Topographic control of snow distribution in an alpine watershed of western Canada inferred from spatially-filtered MODIS snow products |
VerfasserIn |
J. Tong, S. J. Déry, P. L. Jackson |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 3 ; Nr. 13, no. 3 (2009-03-13), S.319-326 |
Datensatznummer |
250011797
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Publikation (Nr.) |
copernicus.org/hess-13-319-2009.pdf |
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Zusammenfassung |
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 <1500 m with decreasing
values with elevation to near 0% (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<0.001). Mean gradients of SCD with
elevation are 3.8, 4.3, and 11.6 days (100 m)−1 for the snow onset
season, snowmelt season, and entire year, respectively. The SF decreases the
standard deviations of SCDs compared to MOD10A2 with a maximum difference
near 0.6 day, 0.9 day, and 1.0 day for the snow onset season, snowmelt
season, and entire year, respectively. |
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