As the world's climate changes, precipitation patterns are changing as well. Previous studies have found that in Europe, the amount of precipitation has been increasing, and a new study shows an increase in the duration of wet periods, potentially affecting the frequency of catastrophic floods.
Using daily rain gauge data from nearly 700 rain gauges in Europe covering the period 1950-2008, Zolina et al. study changes in the duration of wet spells, defined as consecutive days with significant precipitation (more than 1 millimeter/day: 0.04 inches/day).
The authors find that although the total number of wet days has not changed significantly over the past 60 years, the duration of wet periods has been increasing and short rain events have regrouped into longer rainy spells.
In addition, heavy precipitation events are now more commonly part of prolonged periods of rain and have become more intense. Because flooding depends not only on the amount of rain but also on the duration of rainfall, the changing duration of rainy periods could alter the frequency and intensity of floods, which could affect large populations in Europe.
Title: Changing structure of European precipitation: Longer wet periods leading to more abundant rainfalls, Olga Zolina: Meteorologisches Institut, Universitaet Bonn, Bonn, Germany, and P. P. Shirshov Institute of Oceanology, Moscow, Russia; Clemens Simmer, Stefan Kollet: Meteorologisches Institut, Universitaet Bonn, Bonn, Germany; Sergey K. Gulev: P. P. Shirshov Institute of Oceanology, Moscow, Russia; Geophysical Research Letters DOI:10.1029/2010GL042468, 2010