研究使用CESM表明，对气溶胶排放变化的快速和缓慢响应的叠加（先增加后减少），可以使类似拉尼娜的状况的持续时间比预期的长。哈德利环流对气溶胶减少的快速调整，触发了东南太平洋低云、风、蒸发和海表温度之间的联合反馈，导致延伸到赤道太平洋中部的楔形冷却。与此同时，北亚热带单元逐渐增强，导致赤道地表下层降温持续数十年。
据介绍，在赤道东太平洋观测到的地表变暖与气候模型预测的类似厄尔尼诺的变暖模式之间的差异，使气候研究界面临着挑战。虽然人为气溶胶被认为是一个原因，但赤道太平洋上空持续变冷的趋势，似乎与20世纪80年代以来北半球气溶胶排放的减少相矛盾。
附：英文原文
Title: Contribution of anthropogenic aerosols to persistent La Nina-like conditions in the early 21st century
Author: Hwang, Yen-Ting, Xie, Shang-Ping, Chen, Po-Ju, Tseng, Hung-Yi, Deser, Clara
Issue&Volume: 2024-1-22
Abstract: The discrepancy between the observed lack of surface warming in the eastern equatorial Pacific and climate model projections of an El Nino-like warming pattern confronts the climate research community. While anthropogenic aerosols have been suggested as a cause, the prolonged cooling trend over the equatorial Pacific appears in conflict with Northern Hemisphere aerosol emission reduction since the 1980s. Here, using CESM, we show that the superposition of fast and slow responses to aerosol emission change—an increase followed by a decrease—can sustain the La Nina-like condition for a longer time than expected. The rapid adjustment of Hadley Cell to aerosol reduction triggers joint feedback between low clouds, wind, evaporation, and sea surface temperature in the Southeast Pacific, leading to a wedge-shaped cooling that extends to the central equatorial Pacific. Meanwhile, the northern subtropical cell gradually intensifies, resulting in equatorial subsurface cooling that lasts for decades.
DOI: 10.1073/pnas.2315124121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2315124121