Vegetation Greening and Climate Change Promote Multidecadal Rises of Global Land Evapotranspiration.
Vegetation Greening and Climate Change Promote Multidecadal Rises of Global Land Evapotranspiration.
复制标题
DOI：
10.1038/srep15956
复制
发表时间：
2015-10-30
影响因子：
4.6
通讯作者：
Yu Z
中科院分区：
文献类型：
--
作者：
Zhang K;Kimball JS;Nemani RR;Running SW;Hong Y;Gourley JJ;Yu Z
最近的研究表明，大约在1998年至2008年期间，异常干旱条件和有限的水分供应，特别是在南半球，导致植被生产力下降，土地蒸散量（ET）停止增长。然而，地球气候系统的自然变化会降低确定气候趋势的能力。在这里，我们制作了一个长期（1982-2013年）的基于遥感的陆地ET记录，并调查了全球ET的数十年变化及其根本原因。ET记录显示，在32年的时间里，全球有显著的上升趋势，为0.88 mm yr−2（P < 0.001），主要是由植被绿化（每年0.018%; P < 0.001）和大气水分需求上升（0.75 mm yr−2; P = 0.016）驱动的。我们的研究结果表明，1998年和2008年之间的ET增长减少是一个偶发现象，随后恢复ET增长率后，2008年。陆地降水量也显示出0.66 mm yr−2（P = 0.08）的正趋势，与预期的水循环强化一致，但这一趋势低于蒸发需求和ET的同步增加，这意味着累积供水对ET的限制的可能性。这些趋势的持续很可能加剧区域干旱引起的扰动，特别是在与强厄尔尼诺现象有关的区域干旱气候阶段。
Recent studies showed that anomalous dry conditions and limited moisture supply roughly between 1998 and 2008, especially in the Southern Hemisphere, led to reduced vegetation productivity and ceased growth in land evapotranspiration (ET). However, natural variability of Earth’s climate system can degrade capabilities for identifying climate trends. Here we produced a long-term (1982–2013) remote sensing based land ET record and investigated multidecadal changes in global ET and underlying causes. The ET record shows a significant upward global trend of 0.88 mm yr−2 (P < 0.001) over the 32-year period, mainly driven by vegetation greening (0.018% per year; P < 0.001) and rising atmosphere moisture demand (0.75 mm yr−2; P = 0.016). Our results indicate that reduced ET growth between 1998 and 2008 was an episodic phenomenon, with subsequent recovery of the ET growth rate after 2008. Terrestrial precipitation also shows a positive trend of 0.66 mm yr−2 (P = 0.08) over the same period consistent with expected water cycle intensification, but this trend is lower than coincident increases in evaporative demand and ET, implying a possibility of cumulative water supply constraint to ET. Continuation of these trends will likely exacerbate regional drought-induced disturbances, especially during regional dry climate phases associated with strong El Niño events.