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在过去的60年里,全球干旱的变化很小

Justin Sheffield¹, Eric F Wood, Michael L Roderick

¹Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, USA. justin@princeton.edu

|November 16, 2012

概括

全球变暖可能不会像以前认为的那样增加干旱. 更现实的蒸发模型显示,过去60年干旱的变化很小,影响了气候变化评估.

科学领域:

气候学气候学气候学
水文学的水文学
环境科学环境科学

背景情况:

预计气候变化将在全球范围内增加干旱的频率和严重程度.
以前使用帕尔默干旱严重程度指数 (PDSI) 进行的评估表明,自20世纪70年代以来,全球干旱情况有所增加.
在气候变化下,PDSI的简化蒸发模型可能会在干旱评估中引入偏差.

研究的目的:

通过解决PDSI蒸发模型中的局限性,重新评估全球干旱趋势.
在全球变暖的背景下,更准确地了解最近的全球干旱变化.
为了协调基于PDSI的干旱记录和古气候重建之间的差异.

主要方法:

使用一个简化的水平衡模型,由每月降水和温度数据 (PDSI) 强制执行.
与PDSI结果进行比较,对潜在的蒸发进行了更多基于物理的计算,考虑了能量,湿度和风速.
分析了过去60年的全球干旱变化.

主要成果:

由于简化了蒸发模型,广泛使用的PDSI可能会高估最近全球干旱的增加.
更现实的蒸发计算表明,过去60年全球干旱的变化很小.
这些发现挑战了先前关于全球变暖对干旱的影响的结论.

结论:

全球变暖对水文循环和极端事件的影响需要重新解释.
该研究强调了准确的蒸发建模在气候变化影响评估中的重要性.
结果可能解释了树环干旱数据和PDSI记录之间的差异.

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