Baroclinic Ocean Response to Climate Forcing Regulates Decadal Variability of Ice-Shelf Melting in the Amundsen Sea
Baroclinic Ocean Response to Climate Forcing Regulates Decadal Variability of Ice-Shelf Melting in the Amundsen Sea
复制标题
斜压海洋对气候强迫的响应调节阿蒙森海冰架融化的年代际变化
DOI：
10.1029/2022gl100646
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发表时间：
2022
影响因子：
5.2
通讯作者：
Silvano A
中科院分区：
文献类型：
--
作者：
Silvano A
温暖的海洋沃茨促使阿蒙森海的冰架迅速融化。海洋热量向冰架的输送与阿蒙森暗流有关，阿蒙森暗流是一种近海底的海流，沿着冰架断裂向东流动，并通过槽将温暖的沃茨输送到大陆架上。在这里，我们使用一个区域冰海洋模式来表明，在十年的时间尺度上，暗流的变化是斜压的（深度依赖）。热带太平洋海洋表面十年冷却导致阿蒙森海气旋风异常。这些风的异常驱动了陆架坡折面流的向西扰动和暗流的东向异常（加强），导致冰架融化增加。这与较短的时间尺度形成对比，在较短的时间尺度上，表面流和暗流是协变的，这是一种正压（与深度无关）行为，以前假设适用于所有时间尺度。这表明内部海洋过程介导了阿蒙森海十年期冰架对气候强迫的响应。
Warm ocean waters drive rapid ice‐shelf melting in the Amundsen Sea. The ocean heat transport toward the ice shelves is associated with the Amundsen Undercurrent, a near‐bottom current that flows eastward along the shelf break and transports warm waters onto the continental shelf via troughs. Here we use a regional ice‐ocean model to show that, on decadal time scales, the undercurrent's variability is baroclinic (depth‐dependent). Decadal ocean surface cooling in the tropical Pacific results in cyclonic wind anomalies over the Amundsen Sea. These wind anomalies drive a westward perturbation of the shelf‐break surface flow and an eastward anomaly (strengthening) of the undercurrent, leading to increased ice‐shelf melting. This contrasts with shorter time scales, for which surface current and undercurrent covary, a barotropic (depth‐independent) behavior previously assumed to apply at all time scales. This suggests that interior ocean processes mediate the decadal ice‐shelf response in the Amundsen Sea to climate forcing.