A North–South dipole response of the South Atlantic Convergence Zone during the mid-Holocene

• Main Authors: Wong, Minn Lin, Battisti, David S., Liu, Xiaojuan, Ding, Qinghua, Wang, Xianfeng
• Other Authors: Asian School of the Environment
• Format: Article
• Language: English
• Published: 2024
• Subjects: Earth and Environmental Sciences; Earth atmosphere; Holocenes
• Online Access: https://hdl.handle.net/10356/173699
• Institution: Nanyang Technological University

The South Atlantic Convergence Zone (SACZ) profoundly modulates precipitation from central to southeastern Brazil in the present-day climate. However, the understanding of its long-term behavior responding to various climate forcings remains limited. Here, we use an isotope-enabled atmospheric general circulation model (ECHAM4.6) to examine the precipitation response of the SACZ during the mid-Holocene about six thousand years ago. The model simulates a northward intensification of the SACZ in the mid-Holocene, resulting in a dipole anomaly pattern relative to today's climate. The mid-Holocene precipitation increased along the northern margin of the SACZ due to the strengthening of easterly winds across the tropical Atlantic, while an eastward deflection of the South American low-level jet reduced moisture transport to southern Brazil, resulting in reduced precipitation along the southern margins of the SACZ. The north–south dipole response in precipitation is consistent with the mid-Holocene hydroclimate change observed in proxy records from the region.