Precipitation in Slovenia and its correlation with large-scale atmospheric circulation

What is it about?

This paper examines temporal and spatial variability and trends of annual and seasonal precipitation in Slovenia and their relationship with three atmospheric circulation patterns represented by their indices: North Atlantic Oscillation index (NAOi), Mediterranean Oscillation index (MOi) andWestern Mediterranean Oscillation index (WeMOi). Data from 45 precipitation stations were used for the period 1963–2012.Mean annual precipitation varies from 736 mm in eastern Slovenia to 2,518 mm in northwestern Slovenia. A significant annual precipitation decrease (from −3% to −6% per decade) is observed in western Slovenia. Significant negative trends are observed in southwestern Slovenia in summer (from −4% to −10% per decade) and near the Adriatic coast in spring (from −6% to −10% per decade). Non-significant negative and positive trends are observed in winter and autumn, respectively. Results indicate significant correlations between winter precipitation and MOi (from −0.3 to −0.7), NAOi (from −0.3 to −0.6) andWeMOi (from 0.3 to 0.6). Significant We-MOi influence is observed in spring and autumn, while NAOi and MOi influence has not been detected. Annual precipitation and WeMOi are significantly correlated in central and eastern Slovenia, while significant NAOi and MOi influence is observed in western Slovenia (with the larger area covered by MOi influence).

Featured Image

Why is it important?

Results from this study contribute to a better understanding of relationships between atmospheric circulation patterns and precipitation variability in this transitional area. It is shown that the influence of NAO on precipitation variability over Slovenia is smaller than the effects of the atmospheric circulations belonging to the Mediterranean area (namely WeMO and MO). WeMO appeared as the most dominant atmospheric circulation pattern influencing annual and seasonal precipitation variability and distribution in the Republic of Slovenia, except for winter when MO is the most significant atmospheric circulation pattern.

Perspectives