Observed and modeled changes of the hydrological cycle in Mid-Europe

摘要

Changes in the hydrological cycle in Mid-Europe have been studied for the last six decades and the next four decades. With particular emphasis on precipitation, and with a sideview to runoff and floods, we use observational data and downscaled climate projections to assess the past changes and to estimate future changes at unprecedented spatial resolution and model ensemble size. Mean decadal precipitation changes were found (by other authors) to have occurred in the second half of the last century, with particular increases in the decades after 1970, in parallel to rising temperatures. The increase is strongest with respect to winter precipitation. Positive trends of runoff are found to predominate in Southern and Western Germany, negative trends in Northeastern Germany. For the near future (up to 2040) moderate increases in mean winter precipitation result from the ensemble modeling, in particular for Northern Germany. There is tendency, statistically less certain, that extreme precipitation and runoff, as well in winter and in summer, and duration of dry spells in summer will increase.