HR: 11:50h
AN: SM41D-07    [PDF]
TI: Probabilistic Forecasting of Geomagnetic Indices Using Solar Wind "Air Mass" Analysis
AU: * Siscoe, G
EM: siscoe@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Ave,, Boston, MA 02215 United States
AU: McPherron, R L
EM: rmcpherron@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90024 United States
AU: Zong, Q
EM: zong@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Ave,, Boston, MA 02215 United States
AB: Measurements of the sun's photospheric magnetic field can in principle be used to predict geomagnetic activity one to three days in advance. The accuracy of such predictions is low, however, because they do not include the north-south component of the interplanetary magnetic field (IMF Bz), which is the most geomagnetically relevant parameter. Aside from that carried by large-scale transients, IMF Bz is mainly a product of small-scale, in-transit turbulence and, so, is inherently unpredictable from solar measurements. Routine one-to-three day forecasts of geomagnetic activity based on deterministic algorithms are, therefore, not possible. Probabilistic forecasts offer the next best thing to deterministic forecasts, and air-mass climatology offers a way to develop the advantages inherent in probabilistic forecasts for space weather applications. Here we address the IMF Bz indeterminacy problem (or better, get around it) by applying the concept of air mass climatology to the solar wind. We give criteria and statistics for solar wind air masses, which provide poof of concept for routine, mid-range (one to three day) probabilistic air-mass forecasts of daily levels of geomagnetic activity.
DE: 2134 Interplanetary magnetic fields
DE: 2149 MHD waves and turbulence
DE: 2164 Solar wind plasma
DE: 2722 Forecasting
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting