Statistical modelling of extreme precipitation indices for the Mediterranean area under future climate change
Statistical modelling of extreme precipitation indices for the Mediterranean area under future climate change
复制标题
未来气候变化下地中海地区极端降水指数统计模型
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
J. Jacobeit
中科院分区：
文献类型：
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作者：
E. Hertig;S. Seubert;A. Paxian;G. Vogt;H. Paeth;J. Jacobeit
通过统计降尺度分析了地中海地区极端降水量的预测变化，直到21世纪末。广义线性模型被用作降尺度技术，以评估精细尺度空间分辨率上极端降水的不同百分位数指数。在所考虑的区域，极端降水与大尺度环流的异常以及对流条件有关。为了解释这一点，预测因子的选择包括描述大尺度环流的变量（700 hPa和500 hPa的位势高度，850 hPa的u风和v风分量）以及热力学参数（850 hPa和700 hPa的比湿度，Showalter指数，对流抑制）。在统计降尺度方法的范围内，应用特定的统计集成技术，以允许预测因子-预测因子关系中的非平稳性。因此，统计集合包括一系列极端降水的未来可能演变。两种不同的排放情景（A1 B和B1），每个情景的多次运行，以及两种不同的大气环流模式（ECHAM 5和HadCM 3）的输出，以评估极端降水在温室效应增强的条件下。在地中海地区的许多地区，春季的产量主要下降。在夏季，第勒尼安海、爱奥尼亚海和爱琴海周围的海水温度升高，而地中海西部和北方大部分地区的海水温度预计会降低。秋季，西部和中部许多地区的强降雨量减少。在冬季，地中海地区普遍出现明显的增加。除了使用所有预测因子的评估之外，本文件还表明，不同的预测变量可能导致不同的统计降尺度结果。指出了特定大气条件的变化对局地极端降水的明显影响。
Projected changes of extreme precipitation in the Mediterranean area up until the end of the 21st century are analysed by means of statistical downscaling. Generalized linear models are used as downscaling technique to assess different percentile‐based indices of extreme precipitation on a fine‐scale spatial resolution. In the region under consideration extreme precipitation is related to anomalies of the large‐scale circulation as well as to convective conditions. To account for this, predictor selection encompasses variables describing the large‐scale circulation (geopotential heights of the 700 hPa and 500 hPa levels, u‐ and v‐wind components of the 850 hPa level) as well as thermo‐dynamic parameters (specific humidity of the 850 hPa and 700 hPa levels, Showalter‐Index, convective inhibition). In the scope of the statistical downscaling approach a specific statistical ensemble technique is applied in order to allow for non‐stationarities in the predictors–predictand relationships. Consequently, the statistical ensembles include a range of possible future evolutions of extreme precipitation. Two different emission scenarios (A1B and B1), multiple runs for each scenario, and output of two different general circulation models (ECHAM5 and HadCM3) are applied to assess extreme precipitation under enhanced greenhouse warming conditions. The results yield mainly decreases over many parts of the Mediterranean area in spring. In summer increases are assessed around the Tyrrhenian Sea, the Ionian Sea, and the Aegean Sea, whereas decreases are projected for most of the western and northern Mediterranean regions. In autumn reductions of heavy rainfall occur over many parts of the western and central areas. In winter distinct increases are widespread in the Mediterranean area. Beyond the assessments using all predictors it is shown in the present contribution that different predictor variables can lead to varying statistical downscaling results. It points to distinct impacts of the change of specific atmospheric conditions on local extreme precipitation.
影响因子：
1.2
作者：
E. Hertig;A. Paxian;G. Vogt;S. Seubert;H. Paeth;J. Jacobeit
通讯作者：
E. Hertig;A. Paxian;G. Vogt;S. Seubert;H. Paeth;J. Jacobeit