https://doi.org/10.5194/tc-2020-289

Matiu, M., Crespi, A., Bertoldi, G., Carmagnola, C. M., Marty, C., Morin, S., Schöner, W., Cat Berro, D., Chiogna, G., De Gregorio, L., Kotlarski, S., Majone, B., Resch, G., Terzago, S., Valt, M., Beozzo, W., Cianfarra, P., Gouttevin, I., Marcolini, G., Notarnicola, C., Petitta, M., Scherrer, S. C., Strasser, U., Winkler, M., Zebisch, M., Cicogna, A., Cremonini, R., Debernardi, A., Faletto, M., Gaddo, M., Giovannini, L., Mercalli, L., Soubeyroux, J.-M., Sušnik, A., Trenti, A., Urbani, S., and Weilguni, V. (2020). Observed snow depth trends in the European Alps 1971 to 2019, The Cryosphere Discuss., https://doi.org/10.5194/tc-2020-289, in review.

The European Alps stretch over a range of climate zones, which affect the spatial distribution of snow. Previous analyses of
station observations of snow were confined to regional analyses. Here, we present an Alpine wide analysis of snow depth from
45 six Alpine countries: Austria, France, Germany, Italy, Slovenia, and Switzerland; including altogether more than 2000 stations.
Using a principal component analysis and k-means clustering, we identified five main modes of variability and five regions,
which match the climatic forcing zones: north and high Alpine, northeast, northwest, southeast and southwest. Linear trends
of mean monthly snow depth between 1971 to 2019 showed decreases in snow depth for 87% of the stations. December to
February trends were on average -1.1 cm decade-1
(min, max: -10.8, 4.4; elevation range 0–1000 m), -2.5 (-25.1, 4.4; 1000–
50 2000 m) and -0.1 (-23.3, 9.9; 2000–3000 m), with stronger trends in March to May: -0.6 (-10.9, 1.0; 0–1000 m), -4.6 (-28.1,
4.1; 1000–2000 m) and -7.6 (-28.3, 10.5; 2000–3000 m). However, regional trends differed substantially, which challenges
the notion of generalizing results from one Alpine region to another or to the whole Alps. This study presents an analysis of
station snow depth series with the most comprehensive spatial coverage in the European Alps to date

INARCH

https://doi.org/10.5194/tc-2020-289