Can the Topography of Tibetan Plateau Affect the Antarctic Bottom Water?. Issue 6 (24th March 2021)

• Record Type: Journal Article
• Authors: Wen, Qin; Zhu, Chenyu; Han, Zixuan; Liu, Zhengyu; Yang, Haijun
• Is Part Of: Geophysical research letters. Volume 48:Issue 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-24
• Subjects: Antarctic bottom water -- Bellingshausen Sea -- Tibetan Plateau -- Weddell Sea; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL092448
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The Tibetan Plateau (TP) plays a vital role in shaping global climate. So far, however, few studies have focused on the impact of the TP on Southern Ocean (SO) circulation. Through fully coupled model experiments with and without the TP, we find that removing the TP could eventually enhance Antarctic bottom water (AABW) circulation by generating Rossby wave trains that propagate from the tropical Indo‐Pacific to Amundsen‐Bellingshausen Sea. The surface air temperature (SAT) cools over the Antarctic Peninsula, which then leads to increased brine injection and thus the initial enhancement of AABW. Later on, the increased horizontal salinity transport and oceanic vertical mixing over Bellingshausen Sea further strengthen the AABW. These findings imply that long term changes of AABW can be affected by not only local process but also remote forcing, including those from the Asian highland regions. Plain Language Summary: To understand how the topography of the Tibetan Plateau (TP) may affect Antarctic bottom water (AABW) circulation, we conduct model experiments with and without the TP. We find that removing the TP can enhance the AABW circulation via fast atmosphere teleconnections and subsequent slow ocean adjustments. The TP removal immediately generates a Rossby wave train from Indo‐Pacific to reach at Antarctic coast, resulting in anomalous low‐pressure system over Weddell Sea (WS) and high‐pressure system over Amundsen‐Bellingshausen Sea. The former causes surface air cooling and increases brine injection over WS, which is responsible for the initial AABW strengthening. The latter weakens the westerlies and enhances the southward Ekman transport, which brings saltier water to Bellingshausen Sea. This process takes effect after 600 years and, accompanied by enhanced vertical salinity diffusion, leads to re‐enhancement of AABW circulation. Our study implies that long term changes of AABW can be affected by not only local process but also remote forcing, even those from the Asian highland regions. Key Points: The first study to investigate the potential impact of topography of Tibetan Plateau (TP) on the formation of the Antarctic bottom water (AABW) Removing the TP can enhance AABW circulation via fast atmosphere teleconnections and subsequent slow ocean adjustments The Weddell Sea is responsible for the initial AABW strengthening while the Bellingshausen Sea plays a sustaining role