基于Argo海洋观测资料分析2005～2015年全球比容海平面变化的时空特征

Temporal and Spatial Variations of Global Steric Sea Level Change from Argo Observations,2005-2015

利用3家机构(JAMSTEC、SIO、IPRC)发布的Argo海洋温度和盐度数据分析2005~2015年全球SSL在不同时间和空间尺度上的变化特征。结果表明,全球平均SSL(即由海水密度变化引起的)上升速率为1.08±0.38mm/a;年际信号对SSL变化速率的估算结果存在显著影响,近期(2011~2015年)Argo数据的估算结果(2.16±0.50mm/a)显著大于早期(2005~2010年)的结果(0.66±0.64mm/a)。当前Argo产品用于全球平均SSL变化趋势的分析结果较为一致,差异为3家机构所得结果平均值的10%左右;而小尺度上(20°宽纬度带)的计算结果差异很大,能达到平均值的80%。对全球SSL的空间特征的分析结果也显示,3家机构产品估算的海平面比容变化周年振幅和线性速率在更小的尺度(±5°)上存在不可忽视的差异。

In this paper,ocean temperature and salinity data from three different Argo data processing centers(JAMSTEC,SIO,IPRC)are used to analyze global steric sea level(SSL)change at different temporal and spatial scales during 2005-2015.Our results show that the global mean steric sea level change rate(due to the seawater density variations)is 1.08±0.38 mm/a during 2005-2015.Due to strong inter-annual variations,the SSL rate during the recent period(2011-2015)is significantly greater than that over the earlier period(2005-2010)(2.16±0.50 vs.0.66±0.64 mm/a).Up to now,the 3 Argo estimated global mean long-term SSL trends differ by^10%,compared to their average.However,the differences reach up to 80%(of their average)for regional variations in 6 selected latitude zones(with 20°latitude widths).The spatial patterns of global seasonal and long-term SSL variations show significant differences in small regional scales(e.g.,~5°spatial scales)among the 3 Argo estimates,either.