Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China.
Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China.
Sci Bull (Beijing). 2023 May 30;68(10):1060-1068. doi: 10.1016/j.scib.2023.04.021. Epub 2023 Apr 24.
The Pangea era is an exceptional phase in Earth's history. It is characterized by its hothouse climate state and the latest supercontinent. Thus, it is expected that atmospheric circulation in the Pangea era was largely different from that of the modern world. Here, we study the Hadley circulation in the Pangea era and compare it with that of the present, by performing climate simulations. Our results show that the annual mean Hadley cells are about 20% and 45% weaker than that in the pre-industrial (PI) climate, and their poleward edges are about 2° wider in latitude. The austral winter cell is weakened by 27% and expanded by 2.6°, while the changes of the boreal winter cell are not significant. One distinctive feature is that the ascending branches of the boreal and austral winter cells shift to 23°S and 18°N, respectively, which are much more poleward than their present locations. Our analyses demonstrate that the weakening and widening of the Hadley circulation is due to increasing tropical and subtropical static stability, and that the poleward shifts of the ascending branches of the winter cells are associated with the geographic configuration of the supercontinent Pangea.
泛大陆时期是地球历史上的一个特殊阶段。其特点是温室气候状态和最新的超大陆。因此，预计泛大陆时期的大气环流与现代世界有很大的不同。在这里，我们通过气候模拟研究了泛大陆时期的哈德利环流，并将其与现代的哈德利环流进行了比较。我们的结果表明，年平均哈德利环流比工业化前（PI）气候弱 20%和 45%，其极向边缘在纬度上宽约 2°。南半球冬季环流减弱了 27%，扩张了 2.6°，而北半球冬季环流的变化不明显。一个显著的特点是，冬季环流的上升支在南北半球分别移至 23°S 和 18°N，比现在的位置更偏北。我们的分析表明，哈德利环流的减弱和变宽是由于热带和亚热带静稳度的增加，而冬季环流上升支的北移与超大陆泛大陆的地理配置有关。
