Premium
Nonlinear singular spectrum analysis of the tropical stratospheric wind
Author(s) -
Hsieh William W.,
Hamilton Kevin
Publication year - 2003
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1256/qj.01.158
Subject(s) - singular spectrum analysis , nonlinear system , mode (computer interface) , altitude (triangle) , oscillation (cell signaling) , physics , scale (ratio) , atmospheric sciences , plane (geometry) , climatology , mathematics , meteorology , geology , singular value decomposition , geometry , algorithm , quantum mechanics , biology , computer science , genetics , operating system
The neural‐network‐based nonlinear singular spectrum analysis (NLSSA) is applied to the zonal winds in the 70–10 hPa region (roughly 20–30 km altitude) measured at near‐equatorial stations during 1956–2000. The data are pre‐filtered by the linear singular spectrum analysis (SSA), with the leading eight SSA principal components (PCs) used as inputs for the NLSSA. The NLSSA fits a curve to the data in the eight‐dimensional PC space. This NLSSA curve, when projected onto the two‐dimensional plane spanned by any two PCs, shows the relation between the two SSA PCs. As different SSA modes are associated with different time‐scales, the relations found by the NLSSA reveal the time‐scales between which there are interactions—interactions between the dominant quasi‐biennial oscillation (QBO) time‐scale of about 28 months and the first harmonic at 14 months, and between 28 months and 12 months are found. The anharmonic nature of the QBO is well represented by the NLSSA mode 1, but not by individual SSA modes. The NLSSA is also applied to the time series of the zonal‐wind acceleration. Copyright © 2003 Royal Meteorological Society.