南海上层热含量的年代际变化及影响因子分析

DECADAL VARIABILITY OF UPPER LAYER HEAT CONTENT AND INFLUENCING FACTORS IN THE SOUTH CHINA SEA

南海上层海洋热力结构年代际变化的研究,是海气相互作用与变化研究的热点之一,对南海区域及更大范围的气候异常的研究和南海海洋环流年际变化的研究都具有重要意义。本文采用多套海温、流场和海气界面通量资料,基于热平衡方程和统计分析方法,分析了南海上层热含量的年代际变化,研究了南海上层热含量影响因子的变化特征,比较了混合层及混合层以下热含量变化的异同,进而探讨了影响因子在混合层及混合层以下的不同作用;利用区域积分海温方程后得到的热量收支方程,诊断南海内区不同海域的热收支方程中的各项,发现了不同海域在影响热收支的物理过程方面存在差异。结果表明:南海混合层的热含量的变化主要受海气界面热通量的影响,夹卷效应在热含量的变化中也有接近1/3的贡献。在整个上层400m的热含量变化中,平流效应占据了主导地位。

The study of Interdecadal Variation of oceanic thermal structure in the upper South China Sea is one of the hotspots in the study of air-sea interaction.It is of great significance to the study of climate anomalies and circulation in the South China Sea.To understand the decadal variability of the heat content in the South China Sea(SCS),we studied the difference in heat content between the mixed layer and the layer beneath,the influencing factors,and their roles of play in the two layers,for which multiple datasets were applied and heat balance equation and statistical methods were used.The heat budget in the interior region of the SCS is given,based on which the heat transport and the mechanisms are focused.The results show that the heat content of the upper layer of the SCS has significant decadal variations,so do the air-sea interface net heat flux and advection effects.Moreover,the heat content varies in region as the heat content factors vary in space.The heat content in the mixed layer is affected mainly by the air-sea interface heat flux,of which the entrainment effect contributes nearly one-third.In the layer of entire upper 400m,the advection effects dominate.Therefore,the decadal variability of heat content in the upper layer of the South China Sea features regional characteristics,and the closer to the Pacific Ocean is,the bigger impact of advection would show.