对马海峡水团组成对日本海温盐分布影响的季节及年际变化

The Seasonal and Inter-Annual Variations of the Influences of the Water Masses Structures Along the Tsushima Strait Section on the Temperature and Salinity Distributions Along the Japan Sea Section

基于WOD13(World Ocean Database 2013)的温盐观测资料,分析了对马海峡断面和日本海内一断面上温盐分布的季节变化特征,并利用水团组成混合比的方法探讨了对马海峡断面处的水团组成对日本海内断面上温盐分布的影响的季节和年际变化。研究表明:对马海峡断面上水团组成呈现显著的季节变化。冬季,整个水层被高盐水占据;夏季,对马海峡表层出现高温低盐水,底层为高盐水,次表层为表层低盐水和底层高盐水的混合水体;春秋为过渡季节。日本海断面上,秋季温盐分布最为复杂,表层为高温低盐水,次表层为高盐水,其下为低温高密水。两个断面季节变化对比可以看出,夏季对马海峡断面处的水团组成会影响秋季日本海断面上的温盐分布。夏季对马海峡表层和次表层水是秋季日本海断面表层50m以浅出现低盐水的主要原因;对马海峡深层高盐水主要影响秋季日本海断面50～150m水层,混合比可达0.82;其下为日本海固有水。夏季对马海峡处水团组成的年际变化也会影响秋季日本海断面上温盐分布的年际变化。长江流量较大的年份,夏季对马海峡表层和次表层低盐水的核心盐度值偏低,秋季其在日本海断面上的混合比就高于其他年份;对马海峡底层高盐水在日本海断面上混合比的年际变化则决定于其影响水层上的流场结构和温盐分布。

Based on the observed water temperatures and salinities along the Tsushima Strait Section and the Japan Sea Section from WOD13(World Ocean Database 2013),the seasonal and interannual variations of the influences of the water masses structures along the Tsushima Strait Section on the temperature and salinity distributions along the Japan Sea Section were analyzed.The water masses structures along the Tsushima Strait Section showed obvious seasonal variations.In winter,the whole water column was occupied by the high-salinity water.In summer,the surface water at Tsushima Strait Section was characterized by high temperature and low salinity;the deeper water was of high salinity and the subsurface water was the mixture of the surface water and the deeper water.Compared the seasonal variations of temperatures and salinities along the two sections,it was suggested that the distributions of temperature and salinity at the Japan Sea Section were influenced by the structures of water masses at the Tsushima Strait Section.At the Japan Sea Section,the distributions of temperature and salinity in autumn were most complicated.The surface water was of low salinity,which was influenced by the Tsushima Strait Surface and Subsurface water.The Japan Sea Subsurface water was of high salinity,which was determined by the Tsushima Strait Deeper Water.The deeper water was of low temperature and high density,which was named as the Japan Sea Local Water.The water masses composition along the Tsushima Strait Section caused the inter-annual variations of the temperature and salinity distribution along the Japan Sea Section.The larger Changjiang runoff made the core salinity of summer Tsushima Strait Surface and Subsurface water lower,and therefore the mixing ratios was higher.The mixing ratios of the Tsushima Strait high salinity water to the Japan Sea Section was determined by the current structure and the temperature and salinity distribution in the subsurface layer.