Eco-hydrological responses to recent droughts in tropical South America
Eco-hydrological responses to recent droughts in tropical South America
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DOI：
10.1088/1748-9326/ac507a
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发表时间：
2022-02-01
影响因子：
6.7
通讯作者：
Wang, Guiling
中科院分区：
文献类型：
--
作者：
Jiang, Yelin;Yang, Meijian;Wang, Guiling
本研究基于多个数据源评估了近期南美洲热带地区气象干旱的生态水文效应，并探讨了不同生态水文系统干旱响应和恢复的可能机制。土壤干旱响应和恢复滞后于气象干旱，干旱地区（Nordeste）的延迟时间长于湿润地区（亚马逊河流域），深层土壤的延迟时间长于浅层土壤。蒸散量（ET）和植被在Nordeste是有限的水在正常条件下，并迅速减少浅土壤干旱的发病。在大多数亚马逊地区，水通常是丰富的，ET和植被指数遵循增加，然后减少的模式，增加在干旱开始时，由于增加阳光和减少干旱严重到足以导致从能量有限的制度转变为水有限的制度。气象干旱消亡后，ET和植被迅速恢复在Nordeste与浅层土壤水分（SM）的补充，但需要更长的时间来恢复在亚马逊南部，由于他们对深SM存储的依赖。严重干旱后，在亚马逊河南部的ET和植被指数的负异常往往会持续远远超过土壤干旱结束，表明干旱引起的森林死亡率是缓慢恢复。这项研究的结果可能对未来森林枯死的可能性产生影响，因为预计在温暖的气候中，干旱将变得更加频繁和严重。
This study assesses the ecohydrological effects of recent meteorological droughts in tropical South America based on multiple sources of data, and investigates the possible mechanisms underlying the drought response and recovery of different ecohydrological systems. Soil drought response and recovery lag behind the meteorological drought, with delays longer in the dry region (Nordeste) than in the wet region (Amazonia), and longer in deep soil than in shallow soil. Evapotranspiration (ET) and vegetation in Nordeste are limited by water under normal conditions and decrease promptly in response to the onset of shallow soil drought. In most of the Amazon where water is normally abundant, ET and vegetation indices follow an increase-then-decrease pattern, increase at the drought onset due to increased sunshine and decrease when the drought is severe enough to cause a shift from an energy-limited regime to a water-limited regime. After the demise of meteorological droughts, ET and vegetation rapidly recover in Nordeste with the replenishment of shallow soil moisture (SM), but take longer to recover in southern Amazon due to their dependence on deep SM storage. Following severe droughts, the negative anomalies of ET and vegetation indices in southern Amazon tend to persist well beyond the end of soil drought, indicating drought-induced forest mortality that is slow to recover from. Findings from this study may have implications on the possibility of a future forest dieback as drought is projected to become more frequent and more severe in a warmer climate.