基于Argo浮标资料的西北太平洋模态水的空间结构及年际变化

Spacial Structure and Annual Variation Estimated from Argo Float Data for Subtropical Mode Water in the Northwest Pacific Ocean

基于国际Argo资料中心提供的从2004年1月至2007年10月的浮标剖面资料,对西北太平洋模态水的时空变化特征进行分析。结合WOA01(the World Ocean Atlas 2001)资料,选定模态水主要形成区(30°～35°N,140°～155°E)作为研究区域,利用3月份的平均资料,给出西北太平洋模态水的空间结构为:北边界位于34.5°N附近,南边界可达30°N以南,东边界位于151.5°E,西边界可达140°E以西,深度为350m以浅。通过对模态水核心区的逐月资料分析,揭示了其温度、盐度等的季节变化,并提出一种判别模态水范围的盐度判别法。结合海平面高度异常变化,初步分析了涡旋对模态水的影响,发现涡旋只能暂时改变核心区模态水的温盐结构,之后该区域模态水将基本恢复到正常状态。根据模态水2004-2007年的水文数据特点,发现在过去4a中模态水性质基本稳定,变化很小。

Based on the Argo float profiliug data from International ARGO data center and the WOAOL data （World Ocean Atlas 2001） in the period from Jan, 2004 to Oct, 2007, the features of the spatial structure and temporal variation in the area （30-35°N, 140-155°E） where the North Pacific Subtropical Mode Water （NPSTMW） is formed are analyzed. The monthly mean temperature and salinity for March are used to show the spatial range of NPSTMW. The water has its northern boundary at 34.5°N, its southern at 30°N or further, its eastern at 151.5°E, and its western at 140° or further, and it is shallower than 350 m. The seasonal variation of area is also analyzed by use of the monthly mean temperature and salinity data. At the same time, new method is suggested to define NPSTMW by means of the salinity criterion. Fur thermore the sea level anomaly data are jointly used to analyze the eddy effect on NPSTMW. The results show that eddies only give a short time effect on NPSTMW and the water property will be recovered to the normal conditions after eddies have passed away. Finally as shown from the hydrographic data （2004-2007）, NPSTMW keeps stable and less change in the 4 years time.