Antarctic Bottom Water Warming and Freshening: Contributions to Sea Level Rise, Ocean Freshwater Budgets, and Global Heat Gain
Antarctic Bottom Water Warming and Freshening: Contributions to Sea Level Rise, Ocean Freshwater Budgets, and Global Heat Gain
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DOI：
10.1175/jcli-d-12-00834.1
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发表时间：
2013-08-01
影响因子：
4.9
通讯作者：
Johnson, Gregory C.
中科院分区：
文献类型：
--
作者：
Purkey, Sarah G.;Johnson, Gregory C.
对20世纪80年代至21世纪初南极底层水（AABW）的刷新和变暖进行了量化，评估了水团变化和等温线隆起的相对贡献。该分析使用了高度精确的、全深度的、基于船舶的、沿南大洋周围沿着重复的海洋剖面进行的电导率-温度-深度测量。与1990年代相比，2000年代在南太平洋和南印度洋出现了更新鲜的AABW品种，在邻近南极大陆坡的最新沃茨的新鲜程度最强，并且上升表明该区域产生的AABW的盐度最近发生了变化。底部沃茨在威德尔海表现出显着较少的水团比其他两个南部盆地的淡水化。然而，在整个南大洋，最冷、最深的沃茨的体积都在减少。这种等温线的隆起导致了从底部到浅层最高位温的等深线上的盐化和变暖。在印度洋和太平洋部分，AABW的水团淡化相当于73 +/- 26 Gt yr（-1）的淡水通量，大约是西南极冰盖最近估计质量损失的一半。在2000 m以下和30 ° S以南积分的等温线升沉相当于从AABW的深层体积损失进入深海的34 +/- 14 TW的净热吸收和从相关热膨胀引起的0.37 +/- 0.15 mm/年海平面上升。
Freshening and warming of Antarctic Bottom Water (AABW) between the 1980s and 2000s are quantified, assessing the relative contributions of water-mass changes and isotherm heave. The analysis uses highly accurate, full-depth, ship-based, conductivity-temperature-depth measurements taken along repeated oceanographic sections around the Southern Ocean. Fresher varieties of AABW are present within the South Pacific and south Indian Oceans in the 2000s compared to the 1990s, with the strongest freshening in the newest waters adjacent to the Antarctic continental slope and rise indicating a recent shift in the salinity of AABW produced in this region. Bottom waters in the Weddell Sea exhibit significantly less water-mass freshening than those in the other two southern basins. However, a decrease in the volume of the coldest, deepest waters is observed throughout the entire Southern Ocean. This isotherm heave causes a salinification and warming on isobaths from the bottom up to the shallow potential temperature maximum. The water-mass freshening of AABW in the Indian and Pacific Ocean sectors is equivalent to a freshwater flux of 73 +/- 26 Gt yr(-1), roughly half of the estimated recent mass loss of the West Antarctic Ice Sheet. Isotherm heave integrated below 2000 m and south of 30 degrees S equates to a net heat uptake of 34 +/- 14 TW of excess energy entering the deep ocean from deep volume loss of AABW and 0.37 +/- 0.15 mm yr(-1) of sea level rise from associated thermal expansion.