赤道中东太平洋海温关联指数及其与ENSO强弱作用年相关的研究

Study of tropical middle-eastern Pacific sea surface temperature correlation index and probale correlation with ENSO effects

基于关联度区域平均的方法定义了赤道中东太平洋海表温度的关联指数(TPTI),这一关联指数与多种传统指数具有较多的共性,主要体现了赤道中东太平洋地区海温与其他区域作用强度的变化。同时,指数偏强的年份基本对应了强厄尔尼诺年和拉尼娜年,主要原因在于这些年份温度同步变化的覆盖区域较广,赤道中东太平洋对其他地区的作用较强。因此,厄尔尼诺和拉尼娜事件本身也包含了对全球气候变化的强作用年和弱作用年两种情况。这一关联指数与中国夏季降水联系的研究表明:春季和夏季关联指数与中国夏季降水经验正交分解第一模态的相关系数分别为-0.24和-0.38,前冬和春季关联指数与夏季降水在长江流域和东北地区等均有显著的相关,关联指数大值年和小值年对应的亚欧大陆和北太平洋区域的异常环流形势基本呈反位相配置。因此,这一关联指数具有应用于夏季降水预测的潜在价值,基于网络关联度的指数定义方法可能是气候变化信号指数定义之新的有效途径。

The tropical middle-eastern Pacific temperature correlation index （TPTI） is established based on the area average of the correlation degree. TPTI shows much similarty with traditional indices, which also denotes the correlation actions between the tropical middle-eastern Pacific and other global areas. Besides, the year in which TPTI is higher corresponds usually to the strong E1 Nino or La Nina signal, and the reason might be that temperature synchronization area in the tropical middle-eastern Pacific is lager, and the action between tropical the middle-eastern Pacific and other global areas is stronger. That is to say, strong E1 Nino and La Nina years themselves might cover strong and weak action situations. The research of relation between TPTI and China summer precipitation shows that correlation coefficient between the summer TPTI and the first EOF mode of China summer precipitation field （1966- 2005） is -0.28, and the correlation index for the spring TPTI and the summer pre- cipitation is - 0. 34. Furthermore, the circumfluence background of hight TPTI is quite different from that of low TPTI, which is to say that TPTI might be used in the prediction of China summer precipitation and, a new effective way for the cli- mate signal definition based on the correlation degree of network is thus proposed.