Xia Yan, Hu Yongyun, Liu Jiping
College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China; 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). 2020 Oct 15;65(19):1667-1674. doi: 10.1016/j.scib.2020.06.011. Epub 2020 Jun 10.
There have been extensive studies on poleward expansion of the Hadley cells and the associated poleward shift of subtropical dry zones in the past decade. In the present study, we study the trends in the width and strength of the Hadley cells, using currently available simulation results of the Coupled Model Intercomparison Project Phase-6 (CMIP6), and compare the trends with that in CMIP5 simulations. Our results show that the total annual-mean trend in the width of the Hadley cells is 0.13° ± 0.02° per decade over 1970-2014 in CMIP6 historical All-forcing simulations. It is almost the same as that in CMIP5. The trend in the strength of the Northern-Hemisphere (NH) cell shows much greater weakening in CMIP6 than in CMIP5, while the strength trend in the Southern-Hemisphere (SH) cell shows slight strengthening. Single-forcing simulations demonstrate that increasing greenhouse gases cause widening and weakening of both the NH and SH Hadley cells, while anthropogenic aerosols and stratospheric ozone changes cause weak strengthening trends in the SH cell. CMIP6 projection simulation results show that both the widening and weakening trends increase with radiative forcing.
在过去十年中，人们对哈得莱环流的极向扩张以及亚热带干燥带的相关极向移动进行了广泛研究。在本研究中，我们利用耦合模式比较计划第6阶段（CMIP6）目前可用的模拟结果，研究哈得莱环流的宽度和强度趋势，并将这些趋势与CMIP5模拟结果进行比较。我们的结果表明，在CMIP6历史全强迫模拟中，1970 - 2014年期间哈得莱环流宽度的年平均总趋势为每十年0.13°±0.02°。这与CMIP5中的情况几乎相同。北半球（NH）哈得莱环流强度的趋势在CMIP6中比在CMIP5中减弱得更明显，而南半球（SH）哈得莱环流强度的趋势则略有增强。单强迫模拟表明，温室气体增加会导致NH和SH哈得莱环流变宽和减弱，而人为气溶胶和平流层臭氧变化会导致SH哈得莱环流出现微弱的增强趋势。CMIP6预测模拟结果表明，随着辐射强迫的增加，变宽和减弱趋势都会增强。
