Abstract
Abstract. The aims of the paper are (i) to describe the annual distribution of extreme runoff events on the Mura, Drava and Sava Rivers, (ii) to demonstrate their association with moisture fluxes, and (iii) to explain their annual distribution by moisture flux climatology. Extreme runoff events were defined as rapid increases in daily mean discharge. Moisture flux anomalies were studied within six pixels of the ERA-40 database around the studied region. In general, extreme runoff events were concentrated in the summer and autumn and were usually associated with anomalies in moisture flux, mainly from the south. Nevertheless, while southern and western moisture fluxes were typical of Sava River events that occurred mainly in autumn, summer events prevailed on the Mura River and were frequently associated with moisture fluxes from the east or the north. It is remarkable that moisture fluxes from the west and south have their maxima in the autumn, whereas those from the east and north have their maxima in the summer. Therefore, the climatology of moisture flux seems to be one of the major reasons for the annual distribution of extreme runoff events in the study region. This result should be confirmed in other regions in the future.
Highlights
The Alps are one of the most significant climate boundaries in Europe (Wanner et al, 1997)
Considering the heavy precipitation and floods in the Mediterranean region, they are often associated with convective storms in the warm sectors of cyclones (Homar et al, 2007)
The hydrological data needed for selecting extreme runoff events were provided by the Global Runoff Data Centre (GRDC)
Summary
There are many studies regarding the moisture sources for precipitation in various regions or river basins (e.g., Stohl and James, 2005). A similar finding was confirmed for the Southern Alps too by numerous case studies (Massacand et al, 1998; Reale et al, 2001; Turato et al, 2004). This finding inspired our study for a “quantitative classification of the circulation types” (Muller and Kaspar, 2010). South-eastern Alps were recognised as one of the regions where these events were concentrated in the autumn (Muller et al, 2009a), and were frequently associated with significant moisture flux anomalies from the south or east (Muller and Kaspar, 2010). The aims of the present paper are: (i) to describe the annual distribution of extreme runoff events in the south-eastern Alps (Sect. 3), (ii) to demonstrate their association with moisture fluxes (Sect. 4.2), and (iii) to explain the annual distribution by the moisture flux climatology (Sect. 4.3)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
