Statistical downscaling for climate change projections in the Mediterranean region: methods and results
Statistical downscaling for climate change projections in the Mediterranean region: methods and results
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DOI：
10.1007/s10113-014-0605-0
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发表时间：
2014-05
影响因子：
4.2
通讯作者：
J. Jacobeit;E. Hertig;S. Seubert;K. Lutz
中科院分区：
文献类型：
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作者：
J. Jacobeit;E. Hertig;S. Seubert;K. Lutz
除了区域气候模型的动态降尺度之外，统计降尺度（SD）是在区域甚至局部尺度上得出气候变化预测的主要工具。对于地中海地区，过去二十年发表了越来越多基于不同统计技术的降尺度研究，这些研究涉及不同的变量和区域领域，结果范围广泛，有时甚至不同。本文对这些地中海降尺度研究进行了简要回顾，主要考虑以下两个方面：（1）自20世纪90年代初以来，该领域取得了哪些进展？该综述讨论了降尺度评估中极端值的纳入、概率方法的发展、预测变量集的扩展、动态模型模拟和统计模型评估中集成的使用、预测变量-预测对象关系中非平稳性的考虑，以及与天气降尺度相关的一些进展。 (2) 考虑到动力模型方面的共识和争议点，地中海地区的主要区域气候变化信号是什么？未来预测的最佳一致性可以在季节性气温中找到，冬季和春季升温速率较低，而在大多数情况下，夏季和秋季升温速率较高。对于极端气温的年内范围，得到了不同的结果，但预计高温条件通常会增加。关于季节性降水，春季、夏季和秋季降水量主要减少。然而，对于冬季的预测则明显不同（GCM：降雨量减少；RCM：仅在地中海地区最北部地区降雨量增加；SD：多项研究显示北部和西部地区降雨量普遍增加）。对于极端降雨，得到了不同的结果，但整个降水分布倾向于向更高和更低的值移动。除了一些次区域差异外，未来干旱期持续时间显着增加。对于近地表风，只有少数研究可用，并且他们预测主要在冬季会出现一些下降。
Besides dynamical downscaling by regional climate models, statistical downscaling (SD) is a major tool to derive climate change projections on regional or even local scales. For the Mediterranean area, an increasing number of downscaling studies based on different statistical techniques have been published in the last two decades with a broad range of sometimes differing results relating to different variables and regional domains. This paper gives a short review of these Mediterranean downscaling studies mainly considering the following two aspects: (1) what kind of progress has been realized in this field since the early 1990s? The review addresses the inclusion of extremes in downscaling assessments, the development of probabilistic approaches, the extension of predictor sets, the use of ensembles for both dynamical model simulations and statistical model assessments, the consideration of non-stationarities in the predictor–predictand relationships, and some advances related to synoptic downscaling. (2) What are the main regional climate change signals in the Mediterranean area, considering agreed and controversial points also with respect to dynamical models? Best accordance among future projections can be found in seasonal temperatures with lower rates of warming in winter and spring, and, in most cases, higher ones in summer and autumn. Different results are obtained for the intra-annual range of extreme temperatures, but high-temperature conditions are generally expected to increase. Regarding seasonal precipitation, predominant reductions are indicated for spring, summer, and autumn. For winter, however, projections are distinctly different (GCMs: rainfall decrease; RCMs: increase only in the northernmost parts of the Mediterranean region; SD: widespread increases in the northern and western parts in several studies). Different results are obtained for rainfall extremes, but the entire precipitation distribution tends to shift towards higherandlower values. Apart from some sub-regional deviations, there is a predominant increase in future dry period durations. For near-surface winds, only a few studies are available, and they project some decline mainly for the winter season.