摘要
利用1871—2008年SODA资料和月平均的Levitus资料计算了南海混合层深度(MLD)的季节及年际变化特征。资料分析表明:季风通过流场调整对南海MLD的时空分布特征有显著的影响。南海MLD的距平变化总体上呈上升趋势,南海南部MLD的距平变化趋势和北部的有显著差异,特别在1955年后北部整体呈下降趋势而南部呈上升趋势,二者的显著周期北部为2—3年,南部与整个区域平均的基本相似有2—6年的显著周期。SOI指数对滞后的南海各个区域有较好的相关性。EOF分析表明第一模态整体呈单极型最大变率分布在南海南部,由南往北逐渐减小显著周期2—3年变化为主;第二模态呈偶极子型,显著周期以2—5年变化为主。回归分析表明南海南部深水区域呈现增深的趋势,而吕宋海峡至南海北部陆架区呈变浅趋势,滑动t检验表明南海MLD有6个显著的突变年份。
Based on the Simple Ocean Data Assimilation （SODA） data, characteristics of seasonal and inter-annual variations of the mixed layer depth （MLD） in the South China Sea （SCS） are derived. Data analysis indicates that monsoon has an obvious impact on the temporal and spatial features of MLD in the SCS through an ad- justment of the current field. The MLD of the SCS has a deepening trend in general, however the differences be- tween northern and southern areas are obvious, for example there is a shallowing trend in the north but opposite in the south after 1955. The main period is 2--3a in the north while 2--6a in the south and the area average of the SCS. The variability of MLD was analyzed by the Empirical Orthogonal Function （EOF） and Spectrum method. The first mode shows that the variability is same in the whole area of SCS basically and the main cycle is about 2--3a. The second mode shows that the variability is dipole-type and the main cycle is 2--5a. The trend of MLD in the SCS is different from the north to the south, that is, it is shallowing from the Luzon Strait to the west continental shelf in theSCS, and is deepening in the deep basin of the southern SCS. There are six times suddenly change of MLD detected by moving t-test technique.
出处
《海洋预报》
北大核心
2013年第3期9-17,共9页
Marine Forecasts
基金
中国科学院南海海洋研究所LED开放课题(LED1004)
关键词
南海
混合层深度
季节和年际变化
EOF分析
South China Sea
mixed layer depth
seasonal and interannual variability
EOF analysis
