Aerosol forcing of the position of the intertropical convergence zone since ad 1550
Aerosol forcing of the position of the intertropical convergence zone since ad 1550
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DOI：
10.1038/ngeo2353
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发表时间：
2015-03
影响因子：
18.3
通讯作者：
Harriet E. Ridley;Y. Asmerom;J. Baldini;S. Breitenbach;Valorie V. Aquino;Keith M. Prufer;B. Culleton;V. Polyak;F. Lechleitner;D. Kennett;Minghua Zhang;N. Marwan;C. Macpherson;L. Baldini;Tingyin Xiao;J. Peterkin;J. Awe;G. Haug
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文献类型：
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作者：
Harriet E. Ridley;Y. Asmerom;J. Baldini;S. Breitenbach;Valorie V. Aquino;Keith M. Prufer;B. Culleton;V. Polyak;F. Lechleitner;D. Kennett;Minghua Zhang;N. Marwan;C. Macpherson;L. Baldini;Tingyin Xiao;J. Peterkin;J. Awe;G. Haug
热带辐合带的位置对低纬降水的分布有重要的控制作用。它的位置很大程度上受半球温度差异的控制。自20世纪初以来，人类活动释放的气溶胶可能导致了热带辐合带的南移（参考文献，），在这段时间内，减弱了北方半球相对于南半球的变暖，但这一提议的移动仍然是模棱两可的。在这里，我们重建每月降雨量超过伯利兹在过去的456年中的碳同位素组成的变化，一个良好的日期，每月解决洞穴。我们确定了自1850年以来前所未有的干燥趋势，这表明热带辐合带的南移。这种干燥与北方半球气溶胶排放的增加相吻合，也标志着北方半球温度与记录中早期观察到的热带辐合带位置之间的关系破裂。我们还确定了自1550年以来的九个短暂的干燥事件，每个事件都发生在北方半球的一次大火山爆发之后。我们的结论是，人为气溶胶排放导致了世纪北方热带地区降雨量的减少，并建议在评估热带地区未来降雨量变化时，应考虑气溶胶排放的地理变化。
The position of the intertropical convergence zone is an important control on the distribution of low-latitude precipitation. Its position is largely controlled by hemisphere temperature contrasts,. The release of aerosols by human activities may have resulted in a southward shift of the intertropical convergence zone since the early 1900s (refs , , , , ) by muting the warming of the Northern Hemisphere relative to the Southern Hemisphere over this interval,,, but this proposed shift remains equivocal. Here we reconstruct monthly rainfall over Belize for the past 456 years from variations in the carbon isotope composition of a well-dated, monthly resolved speleothem. We identify an unprecedented drying trend sincead1850 that indicates a southward displacement of the intertropical convergence zone. This drying coincides with increasing aerosol emissions in the Northern Hemisphere and also marks a breakdown in the relationship between Northern Hemisphere temperatures and the position of the intertropical convergence zone observed earlier in the record. We also identify nine short-lived drying events sincead1550 each following a large volcanic eruption in the Northern Hemisphere. We conclude that anthropogenic aerosol emissions have led to a reduction of rainfall in the northern tropics during the twentieth century, and suggest that geographic changes in aerosol emissions should be considered when assessing potential future rainfall shifts in the tropics.