中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室
State Key Laboratory of Numerical Modeling for Atmospheric Sciences and
Geophysical Fluid Dynamics (LASG)
Institute of Atmospheric Physics, Chinese Academy of Sciences

Vol. 4/No. 26 December 2017

[Model development, algorithm, and evaluation] Weighted Composite Analysis

Highlight: To avoid the artificiality of traditional composite analysis, a new method based on covariance called weighted composite analysis was purposed in the study.

 

The arbitrariness of composite analysis due to criterion of defining positive and negative events is an unsolved problem. To deal with it, a new method based on the covariance and defined as weighted composite analysis was developed in this study.Two ideal cases reveal that the new method can eliminate noise more effectively in small sample size, and has a higher signal to noise ratio than the traditional method in some cases. And a real case on the relationship between ENSO and geopotential height over East Asia in summer indicates that the new method shows some similar features with composite analyses, but can effectually avoid some inappropriate conclusions. It therefore provides an alternative approach to investigate linkages between different variables.

 

Figure 1. Performance counts of the signal to noise ratio for weighted composite analysis (WCA) and traditional composite analysis (CA) in various sample size of CA and deviation ratio of noise over signal. “All” represents using all samples corresponding to positive index event.

 

Citation: Xie, Z., Duan, A. and Tian, Q. 2017. Weighted composite analysis and its application: an example using ENSO and geopotential height. Atmospheric Science letters. Doi:10.1002/asl.786
Reference Code: https://github.com/YMI33/method-library
Download: http://onlinelibrary.wiley.com/doi/10.1002/asl.786/full
Contact: Xie Zhiang, xiezhiang@lasg.iap.ac.cn

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E-mail: lasg_newsletter@lasg.iap.ac.cn
Editors:Wangchuanyi(wangcy@lasg.iap.ac.cn); Zhouwenling(zwl@lasg.iap.ac.cn); Lisiying(lisy@lasg.iap.ac.cn)