engleski

Relationships between large-scale atmospheric circulation and monthly precipitation and discharge in the Danube River Basin

The relationship between four monthly Northern Hemisphere (NH) atmospheric circulation indices, defined as Varimax rotated principal components (VRPC) of monthly average 500 hPa surface geopotential heights for the NH, and the Danube River Basin (DRB) monthly precipitation amount anomalies for 26 weather stations and average monthly discharge anomalies for 10 hydrological stations on a major waterway of the DRB was analysed for the period 1961–2010. A weak average correlation was established between the Northern Atlantic Oscillation (NAO), the Eastern Atlantic (EA) and the Scandinavian (SCA) index and the monthly precipitation/discharge anomalies for the DRB, while a more significant average correlation was established for the Eastern Atlantic/Western Russia (EA/WR) index, especially in the winter season. A type of DRB precipitation index, based on principal component analysis (PCA), was used for the classification of DRB monthly precipitation totals and average monthly discharge anomalies into similar space patterns. A mutual relationship between these patterns and the European-Northern Atlantic sea- level composite maps was achieved. The clustering indicated the relationship between synoptic scale spatial features in sea- level pressure anomalies for the European-Northern Atlantic region and the DRB monthly precipitation and discharge anomaly spatial patterns. A statistic of typical pattern frequency of precipitation/ discharge anomalies was obtained and discussed.

Danube Basin, precipitation, discharge, NH atmospheric circulation indices

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