HR: 0800h
AN: SM41A-0333    [Abstracts]
TI: Statistical modeling of storm-level Kp occurrences: Solar-cycle modulation
AU: * Love, J J
EM: jlove@usgs.gov
AF: USGS Geomagnetism Program, Box 25046 MS 966 DFC, Denver, CO 80225, United States
AB: We consider the non-stationary, statistical modeling of the occurrence in time of large Kp geomagnetic storms over the course of multiple solar cycles. Previous work showed that wait times between storms can be represented by an exponential density function, consistent with the realization of a Poisson process. Here we also assume a Poisson process, but to account for solar-cycle modulation of storm likelihood, we assume an occurrence rate given by a parametric constant plus a simple sinusoidal function of time. Parameter estimation is accomplished using maximum likelihood, yielding good fits to the Kp data. We find that the relative phase between storms and sunspots depends on storm size. We quantify previous observations that small storms tend to occur during the declining phase of the solar cycle, whilst large storms tend to occur very close to solar maximum. We predict average wait time between storms and the storm occurrence rate up through the year 2018.
UR: http://geomag.usgs.gov
DE: 2722 Forecasting (7924, 7964)
DE: 2788 Magnetic storms and substorms (7954)
DE: 3245 Probabilistic forecasting (3238)
DE: 7536 Solar activity cycle (2162)
DE: 7974 Solar effects
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting