Large-Scale Synoptic Weather Types and Precipitation Responsible for Landslides in Southern Norway
Open image in new window The contribution of large-scale synoptic weather types to the occurrence of weather-induced landslides was investigated for southern Norway. Landslides from the period 2000–2014 were analyzed on a regional scale, using existing climatic and landslide regionalizations. The classification provides a time series of landslide classes and Kruskal-Wallis tests and chi-tests were conducted to analyze how well the classification performs for each landslide region. The synoptic classification (SynopVis Grosswetterlagen, SVG) of daily weather types was later compared with the precipitation classification. In order to predict the occurrence of landslides within a region, a logistic regression analysis was used where the independent variables were the SVG classes, mean daily rainfall and snowmelt. The results showed that in seven of the twelve landslide regions in southern Norway the SVGs have the highest predictive power in terms of landslide occurrence. In these regions, with the exception of one, the models are significantly better than a null model, and the models are good in predicting weather-induced landslide occurrence. The highest predictive probability of weather-induced landslide occurrence is given by the weather type Zonal Ridge across Central Europe (BM), which yields a 90% probability of weather-induced landslides on the west coast.
KeywordsSynoptic weather types Weather-induced landslides Southern Norway
Many thanks to Paul James from the Deutcher Wetterdienst (DWD) that provided us the complete SVG dataset from 1871 until the summer of 2015.
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