The relationship between the occurrence rate of major stratospheric warmings and solar Lyman-alpha flux

Abstract

The statistical connection between major sudden stratospheric warmings (MSSWs) and solar activity was investigated using the Lyman-alpha flux as a proxy. We subdivided the considered time period between winter 1950-51 and winter 2006-07, for which data about MSSWs is available in discrete time intervals of 4 months, and determined the mean Lyman-alpha flux in them. For the statistical analysis, only those months between December and March, when MSSWs exclusively occurred, were used. Then the range of values of the Lyman-alpha flux was subdivided into discrete bins of 0.25 × 10 11 photons/cm 2 s. Next we determined the frequency at which the mean flux values from the chosen months belonged to the subdivided flux intervals. After that we assigned the number of MSSW occurred under the conditions of a certain Lyman-alpha flux value to the corresponding frequency of the flux values. Finally, we correlated the related MSSW occurrence rate with the discrete Lyman-alpha flux values. The analysis revealed a significant positive correlation between the 11-years solar activity and the occurrence rate of the related MSSWs. Copyright 2007 by the American Geophysical Union.