南海温跃层基本特征及一维预报模式

根据现有1907—1990年南海大面调查资料,按1°×1°网格进行逐月的标准水层的温度统计。在此基础上采用3次样条函数的插值方法计算出整个南海温跃层的深度、厚度和强度并予以相应分析。分析表明,南海温跃层主要分为两种类型:第一类为辐射型,主要分布在南海北部的陆架区内,季节变化显著;第二类为不同水体叠置型,主要分布在广大深水区,它长年存在,季节变化较小。一种温跃层的一维积分预报模式,该模式是基于忽略热平流作用和水平热扩散的前提下,从局部热平衡方程出发,建立了受海面热收支及风混合作用下求解温度垂直分布及温跃层的时空变化。在南海北部水深约300m处进行了单站温跃层后报,结果表明,温跃层的深度、厚度和强度的相对误差均在30％以下。

THE RADICAL CHARACTERISTICS AND THE ONE-DIMENSIONAL CALCULATED PATTERN OF THE SOUTH CHINA SEA THERMOCLINE

The present paper consists of two different parts. The first part describes the averaged characteristics of the thermocline in the South China Sea. Investigation data collected at home and abroad from 1907 to 1990 are analyzed season by season. The statistical charcteristics of the thermocline in the South China Sea are discussed. The results show that the thermocline is of two types. One has radiative characteristics, and mainly appears in the northern shelves of the South China Sea, has evident annual variation, and is notably the strongest in summer, weakest in winter. The other results from the interaction between the seawater masses, exist in the broad deep sea all the year round, and have no variation. The analysis also shows that the thermocline relates to the wind, sea current, tide and so on.The calculated pattern of the thermocline is presented in the second part. Based on some assumptions, the thermocline is studied by means of the one-dimensional heat balance equation for the northern South China Sea. Although it is simple, the calculated pattern agrees well with the observation results. The relative errors are only about 16%, 17%, and 20% in the thermocline depth, thickness and intensity, respectively.