Southern Ocean mixed-layer depth from Argo float profiles
Southern Ocean mixed-layer depth from Argo float profiles
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DOI：
10.1029/2006jc004051
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发表时间：
2008-06-13
影响因子：
3.6
通讯作者：
Talley, Lynne
中科院分区：
文献类型：
--
作者：
Dong, Shenfu;Sprintall, Janet;Talley, Lynne
Argo 浮标的温度、盐度和压力剖面用于得出南大洋的混合层深度 (MLD)。 MLD 是使用位势密度和位温标准根据个体剖面确定的，每月气候学是使用客观制图方法从个体 MLD 得出的。辅助材料中提供了定量数据。每个月MLD的空间结构相似，在太平洋和印度洋的南极绕极流（ACC）内部和北部都有深层混合层。最深的混合层出现在 6 月至 10 月期间，位于 ACC 北部，形成南极中层水 (AAIW) 和亚南极模式水 (SAMW)。对各个 MLD 的检查表明，根据密度和温度标准，深层混合层 (MLD >= 400 m) 集中在 SAMW 密度范围内的狭窄表面密度带中。与历史估计相比，这些与 SAMW 地层相关的深层混合层的表面盐度稍稍更新。太平洋和印度洋海气热交换、风应力和风应力旋度的差异表明，每个洋盆的水形成模式可能受到不同过程的预处理。来自南方的风混合和埃克曼冷水输送可能有助于印度洋 SAMW 的形成。在东太平洋，模式水的形成可能以相对较强的冷却和上升流产生的弱层化为先决条件。
Argo float profiles of temperature, salinity, and pressure are used to derive the mixed-layer depth (MLD) in the Southern Ocean. MLD is determined from individual profiles using both potential density and potential temperature criteria, and a monthly climatology is derived from individual MLDs using an objective mapping method. Quantitative data are available in the auxiliary material. The spatial structures of MLDs are similar in each month, with deep mixed layers within and just north of the Antarctic Circumpolar Current (ACC) in the Pacific and Indian oceans. The deepest mixed layers are found from June to October and are located just north of the ACC where Antarctic Intermediate Water (AAIW) and Subantarctic Mode Water ( SAMW) are formed. Examination of individual MLDs indicates that deep mixed layers ( MLD >= 400 m) from both the density and temperature criteria are concentrated in a narrow surface density band which is within the density range of SAMW. The surface salinity for these deep mixed layers associated with the SAMW formation are slightly fresher compared to historical estimates. Differences in air-sea heat exchanges, wind stress, and wind stress curl in the Pacific and Indian oceans suggest that the mode water formation in each ocean basin may be preconditioned by different processes. Wind mixing and Ekman transport of cold water from the south may assist the SAMW formation in the Indian Ocean. In the eastern Pacific, the formation of mode water is potentially preconditioned by the relative strong cooling and weak stratification from upwelling.