Controls on the Width of Tropical Precipitation and Its Contraction Under Global Warming
Controls on the Width of Tropical Precipitation and Its Contraction Under Global Warming
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DOI：
10.1029/2019gl082969
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发表时间：
2019-08-28
影响因子：
5.2
通讯作者：
Byrne, M. P.
中科院分区：
文献类型：
--
作者：
Donohoe, A.;Atwood, A. R.;Byrne, M. P.
气候模式稳定而一致地模拟了温室气体强迫下热带强降水的缩小。热带降水的经向宽度受热带辐合带（ITCZ）的季节性经向变幅的控制。温室强迫下热带降水的减少是由于ITCZ迁移的季节变化幅度减小所致。提出了一种能量理论，类似于基于向大气输入能量的半球对比的ITCZ移动的能量理论。热带降水的经向宽度与大气加热半球间对比的季节变化范围除以大气跨赤道热输送效率成正比。气候模式偏向于过度膨胀的热带降水，这是由于季节性大气加热的夸大造成的。全球变暖下热带降水的强劲收缩是由于半球间能量输送效率的提高与热带大气总湿稳定性的增强相一致。
Climate models robustly and unanimously simulate narrowing of the intense tropical precipitation under greenhouse gas forcing. We argue that the meridional width of tropical precipitation is controlled by the seasonal meridional range of the Intertropical Convergence Zone (ITCZ). The contraction of tropical precipitation under greenhouse forcing results from a reduced seasonal range of ITCZ migration. An energetic theory-similar to the energetic theory for ITCZ shifts based on the hemispheric contrast of energy input to the atmosphere-is developed. The meridional width of tropical precipitation is proportional to the seasonal range of the interhemispheric contrast in atmospheric heating divided by the efficiency of atmospheric cross-equatorial heat transport. Climate models are biased toward overly expansive tropical precipitation resulting from an exaggerated seasonal atmospheric heating. The robust contraction of tropical precipitation under global warming results from increased efficiency of interhemispheric energy transport consistent with enhanced gross moist stability of the tropical atmosphere.