Wavelet analysis is becoming an increasingly popular tool in the geoscience community due to its good localizations in time and frequency. In this study, wavelet analysis is used to examine the time-frequency structure of the globally integrated atmospheric angular momentum produced by the Goddard Earth Observing Systems data assimilation system. The modulus of the wavelet transform shows distinct oscillations at annual, semi-annual and intraseasonal time scales. A covariance function between the wavelet coefficients and another quantity is developed to quantify their relationships at different time scales. The results show that the global atmospheric angular momentum is associated with seasonal variations of the midlatitude westerlies, intraseasonal variations in the tropical and subtropical regions, and midlatitude planetary-scale and synoptic-scale wave activities.
Siegfried D. Schubert,
"Wavelet analysis of global atmospheric angular momentum", Proc. SPIE 3078, Wavelet Applications IV, (3 April 1997); doi: 10.1117/12.271710; https://doi.org/10.1117/12.271710