HR: 1400h
AN: SH23B-01    [Abstracts]
TI: Analysis of Solar Magnetic Activity with the Wavelet Coherence Method
AU: * VELASCO, V M
EM: vmv@geofisica.unam.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, MEXICO, D.F 04510, Mexico
AU: PEREZ-PERAZA, J A
EM: perperaz@yahoo.com.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, MEXICO, D.F 04510, Mexico
AU: MENDOZA, B E
EM: blanca@geofisica.unam.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, MEXICO, D.F 04510, Mexico
AU: VALDES-GALICIA, J F
EM: jvaldes@geofisica.unam.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, MEXICO, D.F 04510, Mexico
AU: SOSA, O
EM: pr@geofisica.unam.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, MEXICO, D.F 04510, Mexico
AU: ALVAREZ-MADRIGAL, M
EM: mmadrigal@itesm.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, MEXICO, D.F 04510, Mexico
AB: The origin, behavior and evolution of the solar magnetic field is one of the main challenges of observational and theoretical solar physics. Up to now the Dynamo theory gives us the best approach to the problem. However, it is not yet able to predict many features of the solar activity, which seems not to be strictly a periodical phenomenon. Among the indicators of solar magnetic variability there is the 11-years cycle of sunspots, as well as the solar magnetic cycle of 22 years (the Hale cycle). In order to provide more elements to the Dynamo theory that could help it in the predicting task, we analyze here the plausible existence of other periodicities associated with the solar magnetic field. In this preliminary work we use historical data (sunspots and aurora borealis), proxies (Be10 and C14) and modern instrumental data (Coronal Holes, Cosmic Rays, sunspots, flare indexes and solar radio flux at 10.7 cm). To find relationships between different time-frequency series we have employed the t Wavelet Coherence technique: this technique indicates if two time-series of solar activity have the same periodicities in a given time interval. If so, it determines whether such relation is a linear one or not. Such a powerful tool indicates that, if some periodicity at a given frequency has a confidence level below 95%, it appears very lessened or does not appear in the Wavelet Spectral Analysis, such periodicity does not exist . Our results show that the so called Glaisberg cycle of 80-90 years and the periodicity of 205 years (the Suess cycle) do not exist . It can be speculated that such fictitious periodicities hav been the result of using the Fourier transform with series with are not of stationary nature, as it is the case of the Be10 and C14 series. In contrast we confirm the presence of periodicities of 1.3, 1.7, 3.5, 5.5, 7, 60, 120 and 240 years. The concept of a Glaisberg cycle falls between those of 60 and 120 years. We conclude that the periodicity of 120 years is one of the more important feature of Solar Activity which consequences are associated with the earth climatic change.
DE: 2104 Cosmic rays
DE: 2162 Solar cycle variations (7536)
DE: 7519 Flares
DE: 7536 Solar activity cycle (2162)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Joint Assembly