菲律宾海盆深层温盐结构与环流变化特征研究

Research on the variability of the deep ocean thermohaline structure and circulation in Philippine

基于ECCO2(Estimating the Circulation and Climate of the Ocean)、GLORYS12V1(Global Ocean Reanalysis and Simulations)、ORA-S5(Ocean ReAnalysis)三种海洋再分析数据,对比研究了菲律宾海盆深层温盐及环流的季节和年际变化特征。结果表明:三种数据显示的海盆深层温盐季节变化特征基本一致,在3000~4000 m水深区域,海水呈春夏两季高温低盐而秋冬季低温高盐特性,4000 m以下海水温盐季节变化很小;沿西边界,温度与内部有明显差异且季节变化幅度相对较大。沿西边界的输运季节变化特征表现为10月至次年4月输运向南,5—9月输运向北,并且在8月份达最大值;表明存在沿西边界的流动,即菲律宾海盆与南端西卡罗林海盆(West Caroline Basin)之间存在季节性水体交换。海盆深层海水温盐年际变化也十分显著,但不同数据显示的变化特征存在较大差异。EOF和相关分析显示,三种再分析数据的深层位温与ENSO均存在一定相关性,ECCO2的深层位温变化与ENSO的相关性最强。由于长期观测数据较少,再分析数据的结果难以验证,因此目前对年际变化特征的研究仍具有很大的不确定性。

Based on three ocean reanalysis datasets:ECCO2(Estimating the Circulation and Climate of the Ocean),GLORYS12V1(Global Ocean Reanalysis and Simulations)and ORA-S5(Ocean ReAnalysis),this study analyzes the seasonal and inter-annual variation characteristics of the deep ocean thermohaline structure and circulation in the Philippine Basin.The results show that seasonal characteristics of potential temperature and salinity are basically the same in the three datasets.Around 3000~4000 m,the seawater is characterized by high temperature and low salt in spring and summer while low temperature and high salt in autumn and winter,but the seasonal variation of water temperature and salt below 4000 m is very small.Along the western boundary,the potential temperature is significantly different from the interior.The volume transport along the western boundary has anobvious seasonal cycle:the seawater is transported to the south from October to the next year in April,and to the north from May to September,with the maximum in August.This indicates that there is a flow along the western boundary,and it also means that theseasonal exchange of seawater exists between the Philippine Basin and the southern end of the West Caroline Basin.The deep ocean temperature and salinity also reveal clear interannual variability,but these characteristics are quite different among the three datasets.EOF and correlation analysis show that the deep potential temperature of three reanalys is data is related to ENSO phenomenon to a certain extent,and the correlation between the variability of deep potential temperature and ENSO is the strongest in ECCO2 data.Due to the lack of long-term deep-ocean observation,it is difficult to verify the results of reanalysis,so the current study on the inter-annual characteristicsis still of great uncertainty.