Summertime precipitation variability over Europe and its links to atmospheric dynamics and evaporation

Abstract

[1] Gridded monthly precipitation data for 1979-2006 from the Global Precipitation Climatology Project are used to investigate interannual summer precipitation variability over Europe and its links to regional atmospheric circulation and evaporation. The first empirical orthogonal function (EOF) mode of European precipitation, explaining 17.2%-22.8% of its total variance, is stable during the summer season and is associated with the North Atlantic Oscillation. The spatial-temporal structure of the second EOF mode is less stable and shows month-to-month variations during the summer season. This mode is linked to the Scandinavian teleconnection pattern. Analysis of links between leading EOF modes of regional precipitation and evaporation has revealed a significant link between precipitation and evaporation from the European land surface, thus, indicating an important role of the local processes in summertime precipitation variability over Europe. Weaker, but statistically significant links have been found for evaporation from the surface of the Mediterranean and Baltic Seas. Finally, in contrast to winter, no significant links have been revealed between European precipitation and evaporation in the North Atlantic during the summer season.Citation: Zveryaev, I. I., and R. P. Allan (2010), Summertime precipitation variability over Europe and its links to atmospheric dynamics and evaporation,

European precipitation connections with large-scale mean sea-level pressure (MSLP) fields

“…Convective precipitation events are more prevalent in summer (Berg et al 2009), with precipitation generally being larger over the central continental parts of Europe and lower near the continental extremities (Zveryaev 2004). Interestingly, summer evaporation from the North Atlantic is not found to relate to European precipitation, which is in stark contrast to the winter (Zveryaev and Allan 2010). This suggests that the strong winter jet stream and associated extratropical cyclones subside in summer (because of the weaker pole-to-equator temperature gradient), thus limiting this mode of conveyance of North Atlantic moisture and precipitation over Europe.…”

“…In summer (warm-season), smaller-scale processes, such as convection (i.e. thunderstorm activity), are thought to play a key role in precipitation receipt, in part because European precipitation has a significant statistical relationship with European land surface evaporation (Zveryaev and Allan 2010). Convective precipitation events are more prevalent in summer (Berg et al 2009), with precipitation generally being larger over the central continental parts of Europe and lower near the continental extremities (Zveryaev 2004).…”

“…Agriculture, water resources management and other sectors are reliant on timely and sufficient precipitation supply, with extreme variability potentially causing water shortages and crop failures, or flood inundation in both urban and rural areas. Identification of hydroclimatological relationships between largescale climatic circulation and precipitation occurrence helps in understanding the climate drivers of precipitation, which may lead to an improvement in the skill of climate prediction (Zveryaev and Allan 2010). With skilful climate prediction, it would be possible to anticipate precipitation and associated hydrological anomalies, which would help mitigate negative impacts and provide societal benefits.…”

“…As the atmosphere is most dynamically active during winter, most previous analyses have focused on the winter season (Folland et al 2009) and the NAOI, with far less attention given to investigating the large-scale climatic circulation and its impacts in summer (Zveryaev 2004, Zveryaev andAllan 2010). In summer, there is a leading pattern of climatic variability known as the summer North Atlantic Oscillation (SNAO) pattern.…”

“…This variability in precipitation can lead to floods or droughts, which have major socio-economic impacts over Europe (Lorenzo et al 2008, Zveryaev andAllan 2010). Agriculture, water resources management and other sectors are reliant on timely and sufficient precipitation supply, with extreme variability potentially causing water shortages and crop failures, or flood inundation in both urban and rural areas.…”