12th Conference on Middle Atmosphere

Wednesday, 6 November 2002: 11:35 AM
A Clear Signal of the 11-year Solar Cycle in Atmospheric Data
Katie Coughlin, University of Washington, Seattle, WA; and K. K. Tung
There is a clear 11-year solar cycle signal in both the stratophere and troposphere. Much work has been done in the past to describe this signal but the changes in the atmosphere are small and take place over long time periods so it is often difficult to statistically verify the signal's existence. An alternative to the traditional analysis is the EMD (empirical mode decomposition) method. This method is adaptive and therefore highly efficient at identifying embedded structures, even those with small amplitudes. Using this analysis, the geopotential height in the Northern Hemisphere can be completely decomposed into four non-stationary temporal modes: an annual cycle, a QBO signal, an ENSO-like mode, a solar cycle signal and a trend. High correlations with the 10.7 cm radio flux unambiguously establish that the fourth mode is an 11-year solar cycle signal.

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