AGU: Geophysical Research Letters

 

Editors' Highlight

Summertime European drought induced by wintertime rainfall shortages around the northern Mediterranean

As human influence on climate increases, many models predict more frequent extreme weather events, such as the heat wave experienced by Europe in the summer of 2003 that severely affected human health, vegetation productivity, and air quality. Noting that the underlying regional climate mechanisms through which this extreme event developed are poorly understood, Vautard et al. (2007) analyzed meteorological records spanning the past 58 years to search for undiscovered weather patterns that could help explain such heat waves. They discovered that hot summers are preceded by winter rainfall deficits over southern Europe, creating a mass of anomalously warm, dry air that spreads northward through Europe in early summer. Further, the authors found that previous winter and early spring rainfall frequency in the Mediterranean regions is correlated with summer temperature in continental Europe. Because dry soil inhibits convective cloud formation, the authors suggested that soil water contents in Europe's Mediterranean regions play a critical role in the maintenance of climate across Europe. This conclusion is also supported by numerical simulation experiments of regional atmospheric circulation.

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