The European 2015 drought from a climatological perspective

Abstract

Abstract. The summer drought of 2015 affected a large portion of continental Europe and was one of the most severe droughts in the region since summer 2003. The summer of 2015 was characterized by exceptionally high temperatures in many parts of central and eastern Europe, with daily maximum temperatures 2 °C higher than the seasonal mean (1971–2000) over most of western Europe, and more than 3 °C higher in the east. It was the hottest and climatologically driest summer over the 1950–2015 study period for an area stretching from the eastern Czech Republic to Ukraine. For Europe, as a whole, it is among the six hottest and driest summers since 1950. High evapotranspiration rates combined with a lack of precipitation affected soil moisture and vegetation and led to record low river flows in several major rivers, even beyond the drought-hit region. The 2015 drought developed rather rapidly over the Iberian Peninsula, France, southern Benelux and central Germany in May and reached peak intensity and spatial extent by August, affecting especially the eastern part of Europe. Over the summer period, there were four heat wave episodes, all associated with persistent blocking events. Upper-level atmospheric circulation over Europe was characterized by positive 500 hPa geopotential height anomalies flanked by a large negative anomaly to the north and west (i.e., over the central North Atlantic Ocean extending to northern Fennoscandia) and another center of positive geopotential height anomalies over Greenland and northern Canada. Simultaneously, the summer sea surface temperatures (SSTs) were characterized by large negative anomalies in the central North Atlantic Ocean and large positive anomalies in the Mediterranean basin. Composite analysis shows that the western Mediterranean SST is strongly related to the occurrence of dry and hot summers over the last 66 years (especially over the eastern part of Europe). The lagged relationship between the Mediterranean SST and summer drought conditions established in this study can provide valuable skill for the prediction of drought conditions over Europe on interannual to decadal timescales.

Climate signals in carbon and oxygen isotope ratios ofPinus cembratree‐ring cellulose from the Călimani Mountains, Romania

“…Analysed period: 1876-2012 [Colour figure can be viewed at wileyonlinelibrary.com] values correspond to negative SST anomalies over the Mediterranean Sea and the Black Sea and positive SST anomalies over the Atlantic Ocean (Figure 7f). Overall, the structure of the SST anomalies in Figure 7 resembles the SST anomalies responsible for the occurrence of extreme drought events over the southern and eastern part of Europe (e.g., 2003, 2015) (Van Lanen et al, 2016Ionita et al, 2017). In a recent paper, Ionita et al (2017) shown that warm Mediterranean SSTs have preceded and occurred concurrently with dry summers over most of the central and eastern part of Europe.…”

“…Significant and stationary spatial correlations were found between δ 18 O and CI and SPEI3 at European level (Figures 4 and 5). In Figure 7c,f, we further examined the relationship between δ 18 O and oceanic conditions, because the occurrence of droughts and heat waves over the European region is significantly affected by adjacent oceanic condition on yearly to decadal time scales (Cassou et al, 2005 (Feudale and Shukla, 2011;Ionita et al, 2012Ionita et al, , 2017Kingston et al, 2013;Ionita, 2015). Following this line, significant correlations between δ 18 O values and North Atlantic Ocean SST indicate possible connections between the moisture availability over the eastern part of Europe and remote ocean areas.…”

Disentangling Drivers of Meteorological Droughts in the European Greater Alpine Region During the Last Two Centuries

“…Several studies investigated the atmospheric drivers of individual extreme drought events in Europe. Ionita et al (2017) analyzed the severe JJA drought of 2015 Van Lanen et al, 2016), finding that this event was triggered and enhanced by four heat waves caused by persistent blocking events and a deflection of the Atlantic storm tracks toward the North. Similarly, the extreme precipitation deficits of the Iberian drought in /2005(García-Herrera et al, 2007 and the devastating JJA drought of 2003 (Black et al, 2004) were caused by anticyclonic circulation in combination with a positive soil moisture-precipitation feedback.…”

Vb Cyclones Synchronized With the Arctic‐/North Atlantic Oscillation

“…Vb cyclogenesis is strongly linked to the upper level atmospheric dynamics interacting with major orography in a low-level baroclinic environment in the WM (e.g., Maheras et al, 2002;Trigo et al, 2002). The increase of WM sea surface temperatures of about +1°C after 1990 (Ionita et al, 2017;their Figure 10d) appears as a plausible explanation for a sustained Vb cyclone occurrence rate. 2.…”