Modeling the recent evolution of global drought and projections for the twenty-first century with the hadley centre climate model
Modeling the recent evolution of global drought and projections for the twenty-first century with the hadley centre climate model
复制标题
DOI：
10.1175/jhm544.1
复制
发表时间：
2006-10-01
影响因子：
3.8
通讯作者：
Christidis, Nikolaos
中科院分区：
文献类型：
--
作者：
Burke, Eleanor J.;Brown, Simon J.;Christidis, Nikolaos
哈德利中心全球气候模式中的气象干旱是使用帕尔默干旱严重程度指数（PDSI）评估的，这是一种常用的干旱指数。在年际时间尺度上，对于大部分的陆地表面，该模型捕捉到观测到的厄尔尼诺-南方涛动和相对湿度和干燥的PDSI的高值和低值分别代表的地区之间的关系。在十年的时间尺度上，在全球的基础上，该模型再现了自1952年以来观察到的干燥趋势（PDSI下降）。一个最佳的检测分析表明，有一个显着的影响，人为排放的温室气体和硫酸盐气溶胶在生产这种干燥的趋势。在区域的基础上，湿润和干燥的特定区域并不总是准确地模拟。在本文中，现代干旱事件被定义为连续时间段，其中PDSI小于1952年至1998年之间PDSI分布的第20个百分位数（即，在任何时候，平均有20%的陆地表面处于干旱状态）。总体而言，该模型预测的事件发生频率略低于观察到的事件，但时间较长。利用《排放情景特别报告》A2排放情景对21世纪世纪干旱的未来预测表明，一些地区的湿润和干燥程度很高，全球总体呈净干燥趋势。例如，极端干旱的陆地面积比例预计将从目前的1%增加到21世纪末的30%。
Meteorological drought in the Hadley Centre global climate model is assessed using the Palmer Drought Severity Index (PDSI), a commonly used drought index. At interannual time scales, for the majority of the land surface, the model captures the observed relationship between the El Nino-Southern Oscillation and regions of relative wetness and dryness represented by high and low values of the PDSI respectively. At decadal time scales, on a global basis, the model reproduces the observed drying trend (decreasing PDSI) since 1952. An optimal detection analysis shows that there is a significant influence of anthropogenic emissions of greenhouse gasses and sulphate aerosols in the production of this drying trend. On a regional basis, the specific regions of wetting and drying are not always accurately simulated. In this paper, present-day drought events are defined as continuous time periods where the PDSI is less than the 20th percentile of the PDSI distribution between 1952 and 1998 (i.e., on average 20% of the land surface is in drought at any one time). Overall, the model predicts slightly less frequent but longer events than are observed. Future projections of drought in the twenty-first century made using the Special Report on Emissions Scenarios (SRES) A2 emission scenario show regions of strong wetting and drying with a net overall global drying trend. For example, the proportion of the land surface in extreme drought is predicted to increase from 1% for the present day to 30% by the end of the twenty-first century.