据研究人员介绍,在2010-2020年期间,东北太平洋(NEP)海表温度(SST)经历了有记录以来最热的十年,表现为几次极端海洋热浪,被称为“暖团”事件,严重影响了北美西海岸的海洋生态系统和极端天气。虽然内部气候年际变率已被认为是个别事件的一个原因,但持续剧烈的NEP-SST变暖的原因仍然是难以捉摸的。
研究表明,除了温室气体(GHG)作用力外,中国在这一时期气溶胶的快速减排可能起着重要作用。中国气溶胶减少引起的对流层异常变暖,产生了从东亚到NEP的大气遥相关,其特征是阿留申低压的增强和南移。
与之相关的大气环流异常通过抑制蒸发冷却,减弱了东北太平洋地区的气候西风带,使那里的海温变暖。在2010-2020年间,气溶胶引起的NEP海温平均变暖,以及内部气候变率和GHG导致的变暖,使得暖团事件更加频繁和强烈。随着人为气溶胶排放的继续减少,NEP暖团事件可能会增加,其规模超出直接辐射效应比例。
附:英文原文
Title: Atmosphere teleconnections from abatement of China aerosol emissions exacerbate Northeast Pacific warm blob events
Author: Wang, Hai, Zheng, Xiao-Tong, Cai, Wenju, Han, Zi-Wen, Xie, Shang-Ping, Kang, Sarah M., Geng, Yu-Fan, Liu, Fukai, Wang, Chuan-Yang, Wu, Yue, Xiang, Baoqiang, Zhou, Lei
Issue&Volume: 2024-5-6
Abstract: During 2010 to 2020, Northeast Pacific (NEP) sea surface temperature (SST) experienced the warmest decade ever recorded, manifested in several extreme marine heatwaves, referred to as “warm blob” events, which severely affect marine ecosystems and extreme weather along the west coast of North America. While year-to-year internal climate variability has been suggested as a cause of individual events, the causes of the continuous dramatic NEP SST warming remain elusive. Here, we show that other than the greenhouse gas (GHG) forcing, rapid aerosol abatement in China over the period likely plays an important role. Anomalous tropospheric warming induced by declining aerosols in China generated atmospheric teleconnections from East Asia to the NEP, featuring an intensified and southward-shifted Aleutian Low. The associated atmospheric circulation anomaly weakens the climatological westerlies in the NEP and warms the SST there by suppressing the evaporative cooling. The aerosol-induced mean warming of the NEP SST, along with internal climate variability and the GHG-induced warming, made the warm blob events more frequent and intense during 2010 to 2020. As anthropogenic aerosol emissions continue to decrease, there is likely to be an increase in NEP warm blob events, disproportionately large beyond the direct radiative effects.
DOI: 10.1073/pnas.2313797121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2313797121