Drier tropical and subtropical Southern Hemisphere in the mid-Pliocene Warm Period
Drier tropical and subtropical Southern Hemisphere in the mid-Pliocene Warm Period
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DOI：
10.1038/s41598-020-68884-5
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发表时间：
2020-08
影响因子：
4.6
通讯作者：
G. Pontes;I. Wainer;A. Taschetto;Alexander Sen Gupta;A. Abe‐Ouchi;E. Brady;W. Chan;D. Chandan;C. Contoux;R. Feng;S. Hunter;Yoichi Kame;G. Lohmann;B. Otto‐Bliesner;W. Peltier;C. Stepanek;J. Tindall;N. Tan;Qiong Zhang;Zhongshi Zhang;Zhongshi Zhang;Zhongshi Zhang
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文献类型：
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作者：
G. Pontes;I. Wainer;A. Taschetto;Alexander Sen Gupta;A. Abe‐Ouchi;E. Brady;W. Chan;D. Chandan;C. Contoux;R. Feng;S. Hunter;Yoichi Kame;G. Lohmann;B. Otto‐Bliesner;W. Peltier;C. Stepanek;J. Tindall;N. Tan;Qiong Zhang;Zhongshi Zhang;Zhongshi Zhang;Zhongshi Zhang
热力学参数意味着全球平均降雨量增加在一个温暖的大气，然而，动力效应可能会导致更显着的区域降水变化的多样性。在这里，我们调查了上新世中期温暖期（~ 3 Ma）的降雨变化，当时温度比前工业时代高2-3ºC，使用上新世模型相互比较项目第1和第2阶段的输出以及敏感性气候模型实验。在上新世中期的模拟中，北方较高的变暖率产生了半球间的温度梯度，使向南的跨赤道能量通量增加了48%。这种增强的能量通量重组了大气环流，导致热带辐合带向北移动，南半球副热带辐合带减弱并向极地移动。这些变化导致南半球热带和亚热带地区比正常情况下更干燥。对上新世中期的评估增加了一个限制因素，即与半球之间不同的变暖速度有关的未来可能变暖的情景。
Thermodynamic arguments imply that global mean rainfall increases in a warmer atmosphere; however, dynamical effects may result in more significant diversity of regional precipitation change. Here we investigate rainfall changes in the mid-Pliocene Warm Period (~ 3 Ma), a time when temperatures were 2–3ºC warmer than the pre-industrial era, using output from the Pliocene Model Intercomparison Projects phases 1 and 2 and sensitivity climate model experiments. In the Mid-Pliocene simulations, the higher rates of warming in the northern hemisphere create an interhemispheric temperature gradient that enhances the southward cross-equatorial energy flux by up to 48%. This intensified energy flux reorganizes the atmospheric circulation leading to a northward shift of the Inter-Tropical Convergence Zone and a weakened and poleward displaced Southern Hemisphere Subtropical Convergences Zones. These changes result in drier-than-normal Southern Hemisphere tropics and subtropics. The evaluation of the mid-Pliocene adds a constraint to possible future warmer scenarios associated with differing rates of warming between hemispheres.