Statistical and dynamical downscaling assessments of precipitation extremes in the Mediterranean area
Statistical and dynamical downscaling assessments of precipitation extremes in the Mediterranean area
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DOI：
10.1127/0941-2948/2012/0271
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发表时间：
2012-02
影响因子：
1.2
通讯作者：
E. Hertig;A. Paxian;G. Vogt;S. Seubert;H. Paeth;J. Jacobeit
中科院分区：
文献类型：
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作者：
E. Hertig;A. Paxian;G. Vogt;S. Seubert;H. Paeth;J. Jacobeit
地中海地区的极端降水事件由不同的秋冬极端降水百分位数指数来定义：超过日降水量第95百分位数的事件数、百分比、总量和这些事件的平均日降水强度。应用典型相关分析的统计降尺度结果和使用区域气候模式REMO的动态降尺度结果绘制了1961-1990年基准期的图，以及未来时间片2021-2050年相对于前一时期的变化幅度。耦合全球环流模式ECHAM5的直接输出作为附加信息源。对两种不同降尺度技术的定性比较表明，在当前气候条件下，动力技术和统计技术都有能力再现地中海地区的极端降水。统计降尺度方法可以很好地表示极端降水事件的频率，而动态降尺度方法则可以充分模拟极端降水事件的强度。关于21世纪中期地中海地区极端降水的变化，预估地中海大部分地区秋冬季极端降水事件的频率将减少。这些事件的平均强度的变化显示出一种相当不均匀的模式，冬季强度增加最有可能发生在暴露于西部的地形海拔，在气候变化条件下，潮湿空气的上升得益于大气湿度的增加。对于超过日降水第95百分位的事件的总降水量，秋季普遍减少，而冬季伊比利亚半岛西部和法国南部增加，土耳其南部、地中海东部地区、意大利部分地区和北非部分地区减少。
Ex treme precipitation events in theMediterranean area have been defined by different percentile-based indices of extreme precipitation for autumn and winter: the number of events exceeding the 95 th percentile of daily pr ecipitation, percentage, total amount, and mean daily intensity of precipitation from these events. Results from statistical downscaling applying canonical correlation analysis as well as from dynamical downscaling using the regional climate model REMO are mapped for the 1961–1990 baseline period as well as for the magnitude of change for the future time slice 2021–2050 in relation to the former period. Direct output of the coupled global circulation model ECHAM5 is used as an additional source of information. A qualitative comparison of the two different downscaling techniques indicates that under the present climate both the dynamical and the statistical techniques have skill to reproduce extreme precipitation in the Mediterranean area. A good representation of the frequency of extreme precipitation events arises from the statistical downscaling approach, whereas the intensity of such events is adequately modelled by the dynamical downscaling. Concerning the change of extreme precipitation in the Mediterranean area until the mid-21 st century, it is projected that the frequency of extreme precipi tation events will decrease in most parts of the Mediterranean area in autumn and winter. The change of the mean intensity of such events shows a rather heterogeneous pattern with intensity increases in winter most likely at topographical elevations exposed to the West, where the uplift of humid air profits by the increase of atmospheric moisture under climate change conditions. For the precipitation total from events exceeding the 95 th percentile of daily precipitation, wi despread decreases are indicated in autumn, whereas in winter increases occur over the western part of the Iberian Peninsula and southern France, and reductions over southern Turkey, the eastern Mediterranean area, parts of Italy and some North African regions.