Deciphering impacts of climate extremes on Tibetan grasslands in the last fifteen years
Deciphering impacts of climate extremes on Tibetan grasslands in the last fifteen years
复制标题
解读近十五年来极端气候对西藏草原的影响
DOI：
10.1016/j.scib.2019.03.012
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发表时间：
2019-04-15
期刊：
影响因子：
18.9
通讯作者：
Piao, Shilong
中科院分区：
文献类型：
--
作者：
Liu, Dan;Wang, Tao;Piao, Shilong
极端气候已经成为陆地生态系统变化的关键驱动因素。青藏高原面临着快速的气候变化，往往倾向于极端气候。但我们对这种极端事件对高山草原的影响缺乏明确的了解。这里我们显示了2001-2015年间极端事件(干旱、极端潮湿、极端寒冷和极端炎热)发生的频率为0.67-4个月(1)，极端降水主要发生在6-8月，极端温度主要发生在5月。干旱和极端潮湿对草地生长造成相反和不对称的影响，干旱引起的减少大于极端潮湿引起的增加。草原对极端温度的响应主要发生在5月份，表现为偶极子状的空间格局，极端高温(冷)事件在东部高原促进(减少)增长，而在西部高原略微减少(增强)增长。对东部高原极端温度的这些相反反应的解释是，极端寒冷的发生减缓了季前温度的积累，推迟了春季物候的触发，而极端炎热则加速了温度的积累。相比之下，在西部高原，对极端寒冷的积极反应是由伴随着高降水引起的。此外，气候事件的高度极端通常导致生长响应的极端程度要低得多，这意味着西藏草原对气候极端的抵抗力相对较高。被测试的生态系统模型不能准确地模拟草原对干旱和极端温度的反应，需要重新参数化，然后才能信任他们对该地区的输出。(三)2019年科学中国出版社。爱思唯尔出版社、科学中国出版社出版。版权所有。
Climate extremes have emerged as a crucial driver of changes in terrestrial ecosystems. The Tibetan Plateau, facing a rapid climate change, tends to favor climate extremes. But we lack a clear understanding of the impacts of such extremes on alpine grasslands. Here we show that extreme events (drought, extreme wet, extreme cold and extreme hot) occurred at a frequency of 0.67-4 months decade (1) during 2001-2015, with extreme precipitation predominantly occurring in June-to-August and extreme temperatures in May. Drought and extreme wet cause opposite and asymmetric effects on grassland growth, with drought-induced reductions greater than increases due to extreme wet. Grassland responses to extreme temperatures, which predominantly occur in May, show a dipole-like spatial pattern, with extreme hot (cold) events enhanced (reduced) growth in the eastern plateau but slightly reduced (enhanced) growth in the western plateau. These opposite responses to extreme temperatures over the eastern plateau are explained by the possibility that the occurrence of extreme cold slows the preseason temperature accumulation, delaying the triggering of spring phenology, while extreme hot hastens the accumulation. In the western plateau, in contrast, positive responses to extreme cold are induced by accompanying high precipitation. Furthermore, high extremeness of climate events generally led to a much lower extremeness in growth response, implying that the Tibetan grasslands have a relatively high resistance to climate extremes. The ecosystem models tested could not accurately simulate grassland responses to drought and extreme temperatures, and require re-parameterization before trust can be placed in their output for this region. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.