Evaluating uncertainties in the projection of future drought
Evaluating uncertainties in the projection of future drought
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DOI：
10.1175/2007jhm929.1
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发表时间：
2008-04-01
影响因子：
3.8
通讯作者：
Brown, Simon J.
中科院分区：
文献类型：
--
作者：
Burke, Eleanor J.;Brown, Simon J.
利用两种模式组合探讨了四种不同干旱指数对未来干旱发生预测的不确定性。第一个集合表达了第三个Hadley中心气候模式参数空间的不确定性，第二个集合是一个多模式集合，它还表达了气候模式过程中的结构不确定性。分别推导了单CO2 （1 × CO2）和双CO2 （2 × CO2）气候下的标准化降水指数（SPI）、降水和潜在蒸发异常（PPEA）、Palmer干旱严重指数（PDSI）和土壤水分异常（SMA）。以相关1 × CO2分布的第20个百分位数定义的中度干旱变化进行了计算。单纯基于降水的SPI，干旱地表比例变化不大。所有其他指标，包括测量大气对水分的需求，都显示出显著的增加，干旱的陆地面积增加了5%-45%。干旱的区域变化存在很大的不确定性。降水减少的地区在整体成员和指数中显示出可重复的干旱增加。在其他地区，干旱变化的标志和幅度取决于指数定义和集合成员，这表明选择适当的干旱指数对影响研究很重要。
The uncertainty in the projection of future drought occurrence was explored for four different drought indices using two model ensembles. The first ensemble expresses uncertainty in the parameter space of the third Hadley Centre climate model, and the second is a multimodel ensemble that additionally expresses structural uncertainty in the climate modeling process. The standardized precipitation index (SPI), the precipitation and potential evaporation anomaly (PPEA), the Palmer drought severity index (PDSI), and the soil moisture anomaly (SMA) were derived for both a single CO2 (1 X CO2) and a double CO2 (2 X CO2) climate. The change in moderate drought, defined by the 20th percentile of the relevant 1 X CO2 distribution, was calculated. SPI, based solely on precipitation, shows little change in the proportion of the land surface in drought. All the other indices, which include a measure of the atmospheric demand for moisture, show a significant increase with an additional 5%-45% of the land surface in drought. There are large uncertainties in regional changes in drought. Regions where the precipitation decreases show a reproducible increase in drought across ensemble members and indices. In other regions the sign and magnitude of the change in drought is dependent on index definition and ensemble member, suggesting that the selection of appropriate drought indices is important for impact studies.