Impact of global warming on the rise of volcanic plumes and implications for future volcanic aerosol forcing
Impact of global warming on the rise of volcanic plumes and implications for future volcanic aerosol forcing
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DOI：
10.1002/2016jd025405
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发表时间：
2016-11-27
影响因子：
4.4
通讯作者：
Quainoo, Adjoa
中科院分区：
文献类型：
--
作者：
Aubry, Thomas J.;Jellinek, A. Mark;Quainoo, Adjoa
火山喷发将含硫气体注入平流层，对气候产生重大影响。喷发羽流的动态也受到气候本身的影响，因为大气分层影响了羽流的高度。我们使用一个完整的羽流模型来评估全球变暖导致的火山羽流最大上升高度的变化，以及来自全球气候模型集合的大气条件，使用三种代表性的浓度路径（RCP）情景。在RCP4.5和RCP8.5情景下，预测的未来三个世纪的大气温度廓线变化降低了对流层和平流层最下层火山柱的高度，增加了对流层顶高度。因此，跨越对流层顶所需的临界物质喷发率在热带地区增加了3倍，在高纬度地区增加了2倍。在RCP4.5和RCP8.5情景下，预计从21世纪后期开始，平流层低层的一些羽流（主要在热带地区，例如Merapi， 2010年）将不会越过对流层顶。这种影响可能导致由小羽流携带进入平流层的SO2平均通量减少类似或等于5-25%，其频率大于平流层火山气溶胶的衰减速度，总通量减少类似或等于2-12%。我们的结果表明，气候和火山气溶胶强迫之间存在正反馈。这种反馈可能对全球变暖速率影响不大，但对了解火山大气输入的长期演变可能证明是重要的。
Volcanic eruptions have a significant impact on climate when they inject sulfur gases into the stratosphere. The dynamics of eruption plumes is also affected by climate itself, as atmospheric stratification impacts plumes' height. We use an integral plume model to assess changes in volcanic plume maximum rise heights as a consequence of global warming, with atmospheric conditions from an ensemble of global climate models, using three representative concentration pathways (RCP) scenarios. Predicted changes in atmospheric temperature profiles decrease the heights of tropospheric and lowermost stratospheric volcanic plumes and increase the tropopause height, for the RCP4.5 and RCP8.5 scenarios in the coming three centuries. Consequently, the critical mass eruption rate required to cross the tropopause increases by up to a factor of 3 for tropical regions and up to 2 for high-latitude regions. A number of recent lower stratospheric plumes, mostly in the tropics (e.g., Merapi, 2010), would be expected to not cross the tropopause starting from the late 21st century, under RCP4.5 and RCP8.5 scenarios. This effect could result in a similar or equal to 5-25% decrease in the average SO2 flux into the stratosphere carried by small plumes, the frequency of which is larger than the rate of decay of volcanic stratospheric aerosol, and a similar or equal to 2-12% decrease of the total flux. Our results suggest the existence of a positive feedback between climate and volcanic aerosol forcing. Such feedback may have minor implications for global warming rate but can prove to be important to understand the long-term evolution of volcanic atmospheric inputs.