热带太平洋障碍层厚度的时空特征分析

Spatiotemporal analysis of tropical Pacific barrier layer thickness

利用中国Argo实时数据中心提供的9 a(2000—2008年)网格化Argo剖面浮标温、盐数据(G Argo),分析热带太平洋障碍层厚度的气候态分布和低频变化特征。气候平均结果表明,较厚的障碍层主要出现于西太平洋暖池区,并有3条纬向障碍层带状分布,从暖池出发向东延伸至120°W,分别位于以15°N,5°N和12°S为中心的纬度带上。经验正交函数(EOF)基本模态分析表明,热带太平洋障碍层低频振荡以季节和年际变化为主,在季节尺度上主要表现为15°N和12°S障碍层纬度带呈反相变化,都在当地冬季最大,夏季最小;在年际尺度上则主要表现为暖池东边界附近障碍层与厄尔尼诺南方涛动(ENSO)相关的变化,以及暖池中部障碍层与热带准2 a周期振荡(TBO)相关的变化。

Based on nine years （2000--2008） of gridded Argo （G-Argo） temperature and salinity data from China Argo Real-time Data Center, the climatological distribution and low-frequency variability of the barrier layer thickness （BLT） of the tropical Pacific Ocean was analyzed. The climatological mean BLT distribution is characterized by relatively large values in the western Pacific warm pool, and three latitudinal bands that extends from the warm pool to 120°W, centered at approximately 15°N°5°N, 12°S, respectively. The leading EOF modes indicate that the low-frequency variability of the tropical Pacific BLT is dominated by seasonal and interannual signals. For the seasonal time scale, the most pronounced mode is an antiphase BLT pattern at the latitudinal bands along 15°N and 12°S, with the largest （smallest） thickness in winter （summer） at the respective hemisphere. For the interannual time scale, there are two important modes of BLT variability, one located near the eastern boundary of the warm pool with a strong correlation to ENSO, and the other centered at the middle of the warm pool, probably related to TBO.