Climate Change and Drought: a Precipitation and Evaporation Perspective
Climate Change and Drought: a Precipitation and Evaporation Perspective
复制标题
DOI：
10.1007/s40641-018-0101-6
复制
发表时间：
2018-09-01
影响因子：
9.5
通讯作者：
Chen, Jiao
中科院分区：
文献类型：
--
作者：
Dai, Aiguo;Zhao, Tianbao;Chen, Jiao
许多研究表明，温室气体（GHG）引起的全球变暖可能会导致增加地表干旱和更多的干旱在世纪，由于减少降水在亚热带和增加蒸发需求与较高的蒸汽压力赤字在温暖的温度下。最近的一些研究认为，在高CO（2）条件下，植物水分利用效率的提高可能会减少蒸发需求，从而缓解干旱。在这里，我们首先讨论了模式预测的降水量和频率的变化，影响地表水平衡和干旱，然后在温室气体引起的变暖的实际和潜在的蒸散量的变化。温室气体引起的变暖和植物的生理变化的影响下，CO2浓度升高对降水，土壤水分和径流进行量化和比较，通过分析不同的模型实验，有和没有生理反应。温室气体引起的变暖的表面干燥效应被发现占主导地位的湿润效应的植物的生理响应增加CO2，导致类似的表面干燥模式在气候模式模拟与或没有生理反应在21世纪。干燥的一部分来自增加的干燥期（即，随着温室气体的增加，干旱指数的直方图趋于平缓，后者导致水文干旱的普遍增加，甚至在平均径流量增加的地区也是如此。因此，平均值的变化模式不能用来代表干旱变化。与预测的21世纪干燥一致，最近对模型实验的分析表明，在末次冰期最大期，陆地表面较为湿润，这意味着冷冰期的尘埃空气可能是由其他因素造成的，如强风和更多的尘埃来源，而不是干燥的陆地表面。最后，在亚热带地区的干燥似乎并不只是一个短暂的响应增加温室气体，变暖和降水变化模式并没有显着变化，随着时间的推移，在500年的模拟与二氧化碳含量增加的完全耦合的气候模式。
Many studies have shown that greenhouse gas (GHG)-induced global warming may lead to increased surface aridity and more droughts in the twenty-first century due to decreased precipitation in the subtropics and increased evaporative demand associated with higher vapor pressure deficit under warmer temperatures. Some recent studies argue that increased water use efficiency by plants under elevatedCO(2) may reduce the evaporative demand and therefore mitigate the drying. Here we first discuss the model-projected changes in precipitation amount and frequency that affect the surface water balance and aridity and then the changes in actual and potential evapotranspiration under GHG-induced warming. The effects of the GHG-induced warming and changes in plants' physiology under elevated CO2 on precipitation, soil moisture, and runoff are quantified and compared by analyzing different model experiments with and without the physiologic response. The surface drying effect of GHG-induced warming is found to dominate over the wetting effect of plants' physiology in response to increasing CO2, leading to similar surface drying patterns in climate model simulations with or without the physiologic response in the twenty-first century. Part of the drying comes from increased dry spells (i.e., more dry days) and a flattening of the histograms of drought indices asGHGs increase, with the latter leading to widespread increases in hydrological drought even over areas with increasing mean runoff. Because of this, the change pattern of the mean cannot be used to represent drought changes. Consistent with the projected drying in the twenty-first century, recent analyses of model experiments suggest wetter land surfaces during the last glacial maximum, which implies that dusty air during cold glacial periods may have resulted from other factors, such as stronger winds and more dust sources, rather than drier land surfaces. Finally, the drying in the subtropics does not appear to be just a transient response to increased GHGs, as the warming and precipitation change patterns do not vary significantly over time in 500-year simulations with increased CO2 contents by a fully coupled climate model.