Cyclic spectral analysis of fluctuations in a GCM simulation

Journal Article · Thu Feb 01 04:00:00 EST 1996 · Journal of the Atmospheric Sciences

DOI:https://doi.org/10.1175/1520-0469(1996)053<0370:CSAOFI>2.0.CO;2· OSTI ID:274300

Huang, Jian-Ping; North, G R ^[1]

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1. Texas A&M Univ., College Station, TX (United States)

Due to the variety of periodic or quasi-periodic deterministic forcings (e.g., diurnal cycle, seasonal cycle, Milankovitch cycles, etc.), most climate fluctuation may be modeled as cyclostationay process since their properties are modulated by these cycles. Difficulties in using conventional spectral analysis to explore the seasonal variation of climate fluctuations have indicated the need for some new statistical techniques. It is suggested here that the cyclic analysis be used for interpreting such fluctuations. The technique, a very simple cyclostationarity stochastic climate model is constructed. The results show that the seasonal cycle strongly modulates the amplitude of the covariance and spectrum. The seasonal variation of intraseasonal oscillations in the Tropics has also be studied in a zonally symmetric all-land planet in the absence of external forcing. The idealized planet has no ocean, no topography. A 15-year length seasonal run of the atmosphere is analyzed with the NCAR Community Climate Model (CCM2, R15). Analysis of the simulation data indicates the prescence of intraseasonal oscillations in the Tropics, which are also localized in the time of year. Both examples suggest these techniques might be useful for analysis of fluctuations that exhibit locality in both frequency and season. 30 refs., 10 figs.

• OSTI ID: 274300
• Journal Information: Journal of the Atmospheric Sciences, Journal Name: Journal of the Atmospheric Sciences Journal Issue: 3 Vol. 53; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATE MODELS
FLUCTUATIONS
FREQUENCY ANALYSIS
GENERAL CIRCULATION MODELS
SEASONAL VARIATIONS