Control of the Oceanic Heat Content of the Getz-Dotson Trough, Antarctica, by the Amundsen Sea Low
Control of the Oceanic Heat Content of the Getz-Dotson Trough, Antarctica, by the Amundsen Sea Low
复制标题
DOI：
10.1029/2020jc016113
复制
发表时间：
2020-08-01
影响因子：
3.6
通讯作者：
Jenkins, Adrian
中科院分区：
文献类型：
--
作者：
Dotto, Tiago S.;Garabato, Alberto C. Naveira;Jenkins, Adrian
南极西部大陆架温暖的绕极深水（CDW）供应的变化是近几十年来南极西部冰架底部融化和变薄的原因。在这里，我们评估CDW供应的变化，其驱动因素，从多年的停泊部署，和一个区域海洋模型跨越，格茨-多特森槽，阿蒙森海。在2010年至2015年期间，槽内的CDW经历了明显的冷却和清新，与等密度线上温盐特性的变化有关。CDW流入率的变化是由当地的风强迫的陆架断裂暗流，这决定了流入的CDW通过倾斜的密度面以上的大陆坡水文特性控制。当地风耦合到阿蒙森海低压（ASL）的低压系统，这是调制的大尺度气候模式通过大气遥相关。在分析期间，更深的ASL与陆架坡折处的向西异常有关。海面坡度的变化减缓了大陆架断裂的暗流，导致进入大陆架的热量减少，从而使Getz-Dotson海槽冷却。因此，目前的工作表明，西南极冰架的命运是密切相关的未来演变的ASL。简单的语言摘要阿蒙森海的冰架融化的热量是由温暖的沃茨淹没大陆架。在这里，我们表明，流入Getz-Dotson槽的沃茨在2010年至2015年期间经历了明显的冷却，这与槽内底部强化电流的减弱有关。这一过程受陆架坡折风的变化控制。东风的减弱影响了大陆坡上方的中层潜流系统，该系统通过倾斜大陆坡上方的密度面控制了暖水的流入。当地的风受到位于阿蒙森海近海的低压系统的调制，称为阿蒙森海低压。阿蒙森海环流受这一低压系统控制，其结构的变化可能影响到西南极大陆架的温暖沃茨，造成该地区冰架融化的后果。
The changing supply of warm Circumpolar Deep Water (CDW) to the West Antarctic continental shelf is responsible for the basal melting and thinning of the West Antarctic ice shelves that has occurred in recent decades. Here we assess the variability in CDW supply, and its drivers, from a multiyear mooring deployed in, and a regional ocean model spanning, the Getz-Dotson Trough, Amundsen Sea. Between 2010 to 2015, the CDW within the trough underwent a pronounced cooling and freshening, associated with changes in thermohaline properties on isopycnals. Variability in the rate of CDW inflow is controlled by local wind forcing of a shelf break undercurrent, which determines the hydrographic properties of inflowing CDW via tilting of density surfaces above the continental slope. Local wind is coupled to the Amundsen Sea Low (ASL) low-pressure system, which is modulated by large-scale climatic modes via atmospheric teleconnections. For the period analyzed, a deeper ASL was associated with westward wind anomaly at the shelf break. Changes in the sea surface slope decelerated the shelf break undercurrent, resulting in less heat accessing the continental shelf and, consequently, a cooling of the Getz-Dotson Trough. Therefore, the present work suggests that the fate of the West Antarctic ice shelves is closely tied to the future evolution of the ASL.Plain Language Summary The heat available for the melting of the ice shelves of the Amundsen Sea is supplied by the warm waters flooding the continental shelf. Here we show that the waters flowing into the Getz-Dotson Trough underwent a pronounced cooling between 2010 and 2015, associated with a weakening of the bottom-intensified currents within the trough. This process was controlled by changes of shelf break winds. A weakening of the eastward wind impacts the middepth undercurrent system above the continental slope, which controls the inflow of warm water via tilting of density surfaces above the slope. The local winds are modulated by the low-pressure system located offshore of the Amundsen Sea, known as the Amundsen Sea Low. The Amundsen Sea circulation is controlled by this low-pressure system, and changes in its configuration can impact the warmer waters flooding the West Antarctic continental shelf, with consequences for the melting of the region's ice shelves.