The effect of volcanic eruptions on global precipitation
The effect of volcanic eruptions on global precipitation
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DOI：
10.1002/jgrd.50678
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发表时间：
2013-08-27
影响因子：
4.4
通讯作者：
Zhang, Xuebin
中科院分区：
文献类型：
--
作者：
Iles, Carley E.;Hegerl, Gabriele C.;Zhang, Xuebin
我们利用HadCM3气候模式过去一千年的模拟集合，研究了全球降水对18次低纬度大火山爆发响应的强大特征。然后，我们测试了这些特征是否可以在20世纪5次火山喷发后的观测陆地降水数据中检测到。千年模拟结果显示，火山爆发后全球平均降水量显著减少，这与之前的研究结果一致。此外，我们发现海洋上的响应在5年左右保持显著，并且与近地表气温响应的时间尺度相匹配。相比之下，陆地降水响应在3年内保持显著，并且比陆地温度反应更快，与气溶胶光学深度和陆地-海洋温度对比的减小相关。在热带地区，后风干燥区与气候湿润区重合较好，而干燥区平均偏湿，但变化具有空间异质性。这种模式与全球变暖下的预测相反，但在物理上是一致的。在观测资料和模拟观测覆盖的模式中，还发现全球平均和热带湿陆地区降水显著减少是对20世纪火山爆发的响应，尽管这对于观测到的北方夏季湿陆地区的响应并不显著。在北方冬季，该模式严重低估了这种全球响应的强度；尽管消除ENSO的影响，但这种差异源于潮湿的热带地区，从而提高了一致性。模拟的降水响应在北方冬季观测中可探测到，而在夏季观测中则不明显。
We examine robust features of the global precipitation response to 18 large low-latitude volcanic eruptions using an ensemble of last millennium simulations from the climate model HadCM3. We then test whether these features can be detected in observational land precipitation data following five twentieth century eruptions. The millennium simulations show a significant reduction in global mean precipitation following eruptions, in agreement with previous studies. Further, we find that the response over ocean remains significant for around 5 years and matches the timescale of the near-surface air temperature response. In contrast, the land precipitation response remains significant for 3 years and reacts faster than land temperature, correlating with aerosol optical depth and a reduction in land-ocean temperature contrast. In the tropics, areas experiencing posteruption drying coincide well with climatologically wet regions, while dry regions get wetter on average, but there changes are spatially heterogeneous. This pattern is of opposite sign to, but physically consistent with, projections under global warming. A significant reduction in global mean and wet tropical land regions precipitation is also found in response to twentieth century eruptions in both the observations and model masked to replicate observational coverage, although this is not significant for the observed wet regions response in boreal summer. In boreal winter, the magnitude of this global response is significantly underestimated by the model; the discrepancy originating from the wet tropical regions although removing the influence of ENSO improves agreement. The modeled precipitation response is detectable in the observations in boreal winter but marginal in summer.