Influence of the East Atlantic/West Russia pattern on precipitation over Serbia

Abstract

It is widely known that the North Atlantic Oscillation (NAO) has an influence on precipitation in Europe. There are other modes of variability such as the East Atlantic (EA) pattern, the East Atlantic/West Russia pattern (EA/WR), the Scandinavia pattern (SCAND), and the Pacific/North American pattern (PNA), which characterize the climate variability in the Northern Hemisphere. In this study, the influence of the EA/WR pattern on precipitation over Europe is examined, with a focus on Serbia. In addition, we explore the combined effects of positive and negative phases of the NAO and EA pattern with the EA/WR pattern, on precipitation over Europe and Serbia. Precipitation data are obtained from the Global Precipitation Climatology Centre (GPCC) and 15 stations from the national observational network in Serbia. Precipitation anomalies have been explored in relation to positive and negative phases of the EA/WR pattern using the monthly GPCC dataset. For the negative (positive) EA/WR phase, positive (negative) precipitation anomalies prevail over the Balkan Peninsula and central Mediterranean in January, February, May, and November, while a negative (positive) one dominates in March, April, September, and during the summer months. There is a strong positive (negative) signal over Portugal in October and over Greece and the Ionian Sea in December, for the positive (negative) EA/WR phase. The precipitation anomalies associated with the negative phase of the EA/WR pattern reflect above (up to 6 mm) average precipitation over Serbia. The positive phase of the EA/WR pattern caused precipitation anomalies below (up to − 8 mm) average precipitation over Serbia. We find that the NAO and EA patterns enhance the influence of the EA/WR pattern on precipitation changes over Serbia. High positive values of precipitation anomalies existed over Serbia for the negative phases of the EA/WR pattern and NAO (up to 12 mm), and EA pattern (up to 10 mm). Negative precipitation anomalies (up to − 12 mm) over Serbia are caused by the positive phase of the EA/WR pattern in combination with the positive phases of the NAO and EA pattern.