Increasing risk of Amazonian drought due to decreasing aerosol pollution
Increasing risk of Amazonian drought due to decreasing aerosol pollution
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DOI：
10.1038/nature06960
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发表时间：
2008-05-08
期刊：
影响因子：
64.8
通讯作者：
Nobre, Carlos A.
中科院分区：
文献类型：
--
作者：
Cox, Peter M.;Harris, Phil P.;Nobre, Carlos A.
亚马逊雨林在气候系统中起着至关重要的作用，通过吸收能量和回收约一半的福尔斯降雨，帮助推动热带地区的大气环流。据估计，该地区（亚马逊）还含有陆地生态系统中储存的总碳的约十分之一，占全球净初级生产力的十分之一（1）。因此，森林对森林砍伐和全球变暖的综合压力的恢复能力受到极大关注（2），特别是因为一些大气环流模型（GCM）预测亚马逊河流域在二十一世纪将严重干旱（3-5）。在这里，我们分析这些气候预测参考2005年干旱在亚马逊河流域西部，这是与异常温暖的北大西洋海面温度（SST）。我们发现，减少旱季（7月至10月）在亚马逊河流域西部的降雨量与南北海温梯度的指数在赤道大西洋（“大西洋N-S梯度”）。我们的气候模式在目前的大气环流模式中是不寻常的，因为它能够再现这种关系，也能够再现观测到的世纪大西洋南北梯度的年代际变率（7），前提是在模式中包括气溶胶的影响（8）。使用同一模式对21世纪进行的模拟（3、8）显示，由于北方半球反射性气溶胶污染的持续减少（9），与2005年干旱相关的SST条件有一种强烈的趋势，变得更加普遍。
The Amazon rainforest plays a crucial role in the climate system, helping to drive atmospheric circulations in the tropics by absorbing energy and recycling about half of the rainfall that falls on it. This region ( Amazonia) is also estimated to contain about one-tenth of the total carbon stored in land ecosystems, and to account for one-tenth of global, net primary productivity(1). The resilience of the forest to the combined pressures of deforestation and global warming is therefore of great concern(2), especially as some general circulation models ( GCMs) predict a severe drying of Amazonia in the twenty- first century(3-5). Here we analyse these climate projections with reference to the 2005 drought in western Amazonia, which was associated(6) with unusually warm North Atlantic sea surface temperatures ( SSTs). We show that reduction of dry-season ( July - October) rainfall in western Amazonia correlates well with an index of the north - south SST gradient across the equatorial Atlantic ( the 'Atlantic N - S gradient'). Our climate model is unusual among current GCMs in that it is able to reproduce this relationship and also the observed twentieth- century multidecadal variability in the Atlantic N - S gradient(7), provided that the effects of aerosols are included in the model(8). Simulations for the twenty- first century using the same model(3,8) show a strong tendency for the SST conditions associated with the 2005 drought to become much more common, owing to continuing reductions in reflective aerosol pollution in the Northern Hemisphere(9).