Systematic change in global patterns of streamflow following volcanic eruptions.
Systematic change in global patterns of streamflow following volcanic eruptions.
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DOI：
10.1038/ngeo2545
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发表时间：
2015-11
影响因子：
18.3
通讯作者：
Hegerl GC
中科院分区：
文献类型：
--
作者：
Iles CE;Hegerl GC
在大规模火山爆发后，全球大部分地区，特别是气候湿润地区，降水减少。平流层火山气溶胶反射阳光，减少蒸发，而表面冷却稳定大气，降低其保水能力。环流变化在区域尺度上调节全球降水减少。尽管河流对人类很重要，但考虑到巨大的自然变异性，火山活动是否会导致水流发生可察觉的变化还不清楚。在这里，我们分析了来自世界各地的50条大河的流量观测记录，这些河流覆盖了20世纪和19世纪后期的2到6次大火山爆发。我们发现，在亚马逊河、刚果河、尼罗河、奥兰治河、鄂布河、叶尼塞河和科雷马河等地爆发后，流量在统计上显著减少。当把邻近河流的数据结合起来——基于气候模型模拟火山爆发后降水增加或减少的地区——在南美洲北部、中非和高纬度亚洲河流以及平均在潮湿的热带和亚热带地区检测到火山爆发后流量显著（p<0.1）减少。我们还发现，南美南部和北美西南部河流的污染显著增加。这表明未来的火山爆发可能会严重影响全球的水资源供应。
Following large explosive volcanic eruptions precipitation decreases over much of the globe, particularly in climatologically wet regions. Stratospheric volcanic aerosols reflect sunlight, which reduces evaporation, whilst surface cooling stabilises the atmosphere and reduces its water-holding capacity. Circulation changes modulate this global precipitation reduction on regional scales. Despite the importance of rivers to people, it has been unclear whether volcanism causes detectable changes in streamflow given large natural variability. Here we analyse observational records of streamflow volume for fifty large rivers from around the world which cover between two and 6 major volcanic eruptions in the 20th and late 19th century. We find statistically significant reductions in flow following eruptions for the Amazon, Congo, Nile, Orange, Ob, Yenisey and Kolyma amongst others. When data from neighbouring rivers are combined - based on the areas where climate models simulate either an increase or a decrease in precipitation following eruptions – a significant (p<0.1) decrease in streamflow following eruptions is detected in northern South American, central African and high-latitude Asian rivers, and on average across wet tropical and subtropical regions. We also detect a significant increase in southern South American and SW North American rivers. This suggests that future volcanic eruptions could substantially affect global water availability.