| Volumes and Issues Contents of Issue 5 |
www.the-cryosphere-discuss.net/5/2409/2011/
doi:10.5194/tcd-5-2409-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Inter-annual variations of snow days over Switzerland from 2000–2010 derived from MODIS satellite data
Swiss GCOS Office, Federal Office of Meteorology and Climatology, MeteoSwiss, Kraehbuehlstrasse 58, P.O. Box 514, 8044 Zurich, Switzerland
Abstract. Snow cover plays a vital role in the Swiss Alps and therefore it is of major interest to determine and understand its variability on different spatiotemporal scales. Within the activities of the National Climate Observing System (GCOS Switzerland) inter-annual variations of snow days over Switzerland were derived from 2000 to 2010 based on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra satellite. To minimize the impact of cloud cover on the MODIS snow product MOD10C1, we implemented a post-processing technique based on a forward and backward gap-filling approach. Using the proposed methodology it was possible to determine the total number of annual snow days over Switzerland from 2000 to 2010 (SCDMODIS). The accuracy of the calculated snow days per year were quantitatively evaluated against three in situ snow observation sites representing different climatological regimes (SCDin_situ). The correlation (c) between annual SCDMODIS and SCDin_situ is highest for the lowland regions by (c = 0.90) with a slightly lower correlation for the Central Alps of 0.82 and a mean absolute difference of −6 to −7 days (SCDin_situ − SCDMODIS). Differences were further analysed on a monthly and daily resolution over the entire period. The overall agreement between SCDMODIS and SCDin_situ on a daily basis over 10 yr is 88 % to 94 %, depending on the regional characteristics of each validation site. Differences between SCDMODIS and SCDin_situ vary with higher mean absolute differences during the snow accumulation period in autumn and smaller differences after spring, in particularly for the Central Alps. These findings are in agreement with other studies.
Discussion Paper (PDF, 1262 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (TC)
Notice on Discussion StatusCitation: Foppa, N. and Seiz, G.: Inter-annual variations of snow days over Switzerland from 2000–2010 derived from MODIS satellite data, The Cryosphere Discuss., 5, 2409-2435, doi:10.5194/tcd-5-2409-2011, 2011. Bibtex EndNote Reference Manager XML
