Hofstätter Michael, Lexer Annemarie, Homann Markus, Blöschl Günter
Department of Climate Research Central Institute for Meteorology and Geodynamics Vienna Austria.
Institute of Geography, Physical Geography and Quantitative Methods, University of Augsburg Germany.
Int J Climatol. 2018 Apr;38(Suppl Suppl 1):e497-e517. doi: 10.1002/joc.5386. Epub 2017 Dec 21.
Precipitation patterns over Europe are largely controlled by atmospheric cyclones embedded in the general circulation of the mid-latitudes. This study evaluates the climatologic features of precipitation for selected regions in central Europe with respect to cyclone track types for 1959-2015, focusing on large-scale heavy precipitation. The analysis suggests that each of the cyclone track types is connected to a specific pattern of the upper level atmospheric flow, usually characterized by a major trough located over Europe. A dominant upper level cut-off low (COL) is found over Europe for strong continental (CON) and van Bebber's type (Vb) cyclones which move from the east and southeast into central Europe. Strong Vb cyclones revealed the longest residence times, mainly due to circular propagation paths. The central European cyclone precipitation climate can largely be explained by seasonal track-type frequency and cyclone intensity; however, additional factors are needed to explain a secondary precipitation maximum in early autumn. The occurrence of large precipitation totals for track events is strongly related to the track type and the region, with the highest value of 45% of all Vb cyclones connected to heavy precipitation in summer over the Czech Republic and eastern Austria. In western Germany, Atlantic winter cyclones are most relevant for heavy precipitation. The analysis of the top 50 precipitation events revealed an outstanding heavy precipitation period from 2006 to 2011 in the Czech Republic, but no gradual long-term change. The findings help better understand spatio-temporal variability of heavy precipitation in the context of floods and may be used for evaluating climate models.
欧洲的降水模式在很大程度上受中纬度地区大气环流中嵌入的气旋控制。本研究评估了1959 - 2015年期间中欧选定地区降水的气候特征，具体涉及气旋路径类型，重点关注大范围强降水。分析表明，每种气旋路径类型都与特定的高层大气环流模式相关，其通常特征是欧洲上空存在一个主要低压槽。在从东部和东南部移入中欧的强大陆性（CON）气旋和范·贝伯尔型（Vb）气旋影响下，欧洲上空会出现一个占主导地位的高层切断低压（COL）。强Vb气旋的停留时间最长，主要是由于其呈圆形的移动路径。中欧气旋降水气候在很大程度上可以通过季节性路径类型频率和气旋强度来解释；然而，还需要其他因素来解释初秋的第二个降水峰值。路径事件中大量降水总量的出现与路径类型和地区密切相关，在捷克共和国和奥地利东部，夏季所有Vb气旋中有45%与强降水相关，这一比例为最高值。在德国西部，则是大西洋冬季气旋与强降水最为相关。对前50次降水事件的分析显示，捷克共和国在2006年至2011年期间出现了一段显著的强降水期，但没有长期的渐变趋势。这些研究结果有助于更好地理解洪水背景下强降水的时空变异性，并可用于评估气候模型。
