南京师范大学孙炜毅教授团队研究了千年来蒙古高原十年际干旱对外作用力和内部变率的响应。该研究于2024年12月12日发表于国际一流学术期刊《大气科学进展》杂志上。

据悉，自20世纪中叶以来，蒙古高原（MP）经历了十年际干旱和极端热浪，严重影响了区域生态和社会发展。然而，十年尺度的复合热浪-干旱事件背后的机制仍存在争议。

研究团队基于社区地球系统模式上千年集合（CESM-LME）的重建和模拟，证明了在过去一千年中，MP在温暖和寒冷条件下都发生过十年际的干旱，与最近的复合干热事件不同。研究发现，通过研究这些干旱时期的温度变化，可以简单而有效地区分外部作用力和内部变率的不同影响。具体来说，干冷事件主要是由火山爆发引起的，火山爆发削弱了东亚夏季风和中纬度西风带，减少了水汽输送到MP。

相比之下，暖干事件主要是由内部变率引起的，特别是大西洋多年代际涛动的负相和巴伦支海海冰范围的扩大。最近的干热事件可能受到人为作用力和内部变率的综合影响。这些发现加深了人们对外部作用力和内部变率，如何影响MP十年际干旱事件的理解，并强调了最近的复合热浪-干旱事件在上个千年的背景下是前所未有的。

附：英文原文

Title: Response of decadal droughts on the Mongolian Plateau to external forcings and internal variability over the last millennium

Author: Guangyao Hao, Weiyi Sun, jian liu, Liang Ning, Mi Yan

Issue&Volume: 2024-12-12

Abstract: Since the mid-twentieth century, the Mongolian Plateau (MP) has experienced decadal droughts coupled with extreme heatwaves, severely affecting regional ecology and social development. However, the mechanisms behind the decadal-scale compound heatwave-drought event remain debated. Here, using reconstructions and simulations from the Community Earth System Model Last Millennium Ensemble (CESM-LME), we demonstrate that over the last millennium, decadal droughts on the MP occurred under both warm and cold conditions, differing from the recent compound hot-dry event. We found that by examining temperature changes during these drought periods, the distinct influences of external forcings and internal variability can be simply and effectively distinguished. Specifically, cold-dry events were primarily driven by volcanic eruptions that weakened the East Asian summer monsoon and mid-latitude westerlies, reducing moisture transport to the MP. In contrast, warm-dry events were predominantly induced by internal variability, notably the negative phase of the Atlantic Multidecadal Oscillation and the expansion of the Barents Sea ice extents. The recent hot-dry event is probably influenced by the combined effects of anthropogenic forcings and internal variability. These findings deepen our understanding of how external forcings and internal variability affect decadal drought events on the MP and highlight that the recent compound heatwave-drought event is unprecedented in the context of the last millennium.

DOI: 10.1007/s00376-024-4301-9

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-024-4301-9viewType=HTML