过去500年印度夏季风降水与ENSO的关系

为了研究大尺度背景场对ENSO和印度夏季风降水关系的调制作用,更好地预报气候变暖背景下印度夏季风降水的年际变化,本文利用重建的10套ENSO指数和印度降水资料,研究了ENSO和印度夏季风降水在过去500 a(1470—1999年)中的关系,其存在的原因以及如何理解这一现象,主要侧重于ENSO对印度夏季风的影响。结果表明:1)在过去500 a中,ENSO与印度夏季风降水的关系并非是一成不变的,大体上呈现负相关关系;在小冰期负相关较弱,在现代暖期负相关加强,19世纪80年代后负相关开始减弱。2)在过去500 a中,印度夏季风降水异常与ENSO的关系是确定存在的,并非是随机产生的。3)在小冰期和现代暖期,印度夏季降水异常与Ni1o指数的振幅及周期的关系有很大的不同,现代暖期明显较大,即相对于小冰期,现代暖期ENSO的振幅增强、周期偏大,导致印度夏季风与ENSO呈现较强的负相关关系;但两者的平均状态相差不大。

Relationship between Indian summer monsoon precipitation and ENSO in the past 500 years

In order to study the modulation effect of large-scale background field on the relationship between ENSO and Indian summer monsoon precipitation, and to better predict the interannual variation of Indian summer monsoon precipitation under the climate warming background, this paper studies the relationship between ENSO and Indian summer monsoon precipitation in the past 500 years based on ten sets of reconstructed ENSO indices and Indian precipitation data, the reasons for its existence and how to understand this phenomenon.This paper mainly focuses on the influence of ENSO on Indian summer monsoon.Results show that, firstly, the relationship between ENSO and Indian summer monsoon precipitation is not immutable in the past 500 years (1470-1999), generally shows a negative correlation.The negative correlation is weak during Little Ice Age (LIA) and strengthened during Current Warm Period (CWP), but begins to weaken after the 1980s.Secondly, the relationship between Indian summer monsoon precipitation anomaly and ENSO in the past 500 years is certain, not random.Thirdly, the relationship between the Indian summer monsoon precipitation anomaly and the amplitude and cycle of Niño indices are very different during LIA and CWP.The amplitude and cycle of ENSO during CWP are significantly larger than those during LIA, which leads to a stronger negative correlation between Indian summer monsoon and ENSO during CWP.But the average states of the two periods are almost same.