HR: 0830h
AN: SH41B-0466    [PDF]
TI: Near Real Time Prediction of Magnetic Storm Intensity and Timing from Measurements of North to-South Interplanetary Magnetic Clouds
AU: Wu, C
EM: wuc@cspar.uah.edu
AF: CSPAR/The University of Alabama in Huntsville, CSPAR/UAH, Huntsville, AL 35899 United States
AU: Wu, C
EM: wuc@cspar.uah.edu
AF: GSFC/NASA, Laboratory of Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771 United States
AU: * Lepping, R P
AF: GSFC/NASA, Laboratory of Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Berdichevsky, D B
AF: GSFC/NASA, Laboratory of Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Berdichevsky, D B
AF: L3 Cmmunications EER Systems, Inc., L3 Cmmunications EER Systems, Inc., Largo, MD 20774 United States
AB: The importance of interplanetary magnetic clouds to the study of geomagnetic activity has been known for many years, and because of the general characteristics of these large structures, such activity is often major. A program is developed from which we are able to predict the Dst index based on real-time measurements of a magnetic cloud passing Earth, as well as from guidance from previously modeled magnetic clouds (MCs) from WIND observations. The scheme could be applicable to ACE data, for example, or to that of any near real-time field and plasma monitoring platform. The program consists of five stages: (1) identification of the proximity of a cloud-complex (i.e., MC and immediate upstream region), (2) finding, relatively accurately, the front boundary of the MC, (3) estimating the MC's 'center time,' (4) predicting the speed and minimum IMF-BZ and the latter's timing within the MC (based on these earlier findings), and finally (5) estimating the associated Dst, based on reliable IMF-BZ vs. Dst relations. The initial identification of the cloud-complex is carried out by examining proton plasma beta, degree of smoothness of the magnetic field's directional change, and field strength. These alone will help to pin down the front boundary of the MC to within about $\pm$ 2 hr. This identification then triggers an attempt to determine this boundary to within $\pm$ 1/2 hr using finer scale field data After viewing about 2/3 of a MC-passage and properly estimating the MC's center time, for North-to-South types of MCs, which are expected to be most common in the near future [Bothmer and Rust, 1997], we have sufficient information to predict min-Bz within the MC, provided reasonable front-to-back MC symmetry exist. Application of the scheme to MCs that occurred over the period 1995 through 2002 is used to determine its effectiveness in predicting Dst, as well as to simply determine the program's ability to identify MCs of any type (i.e., including S-to-N types) and their front boundary times. In the prediction mode (i.e., for N to-S types) the scheme does not strictly require that the observing spacecraft be upstream of Earth, since 7 or so hours lead-time, for the prediction, is gained for most MCs in Earth's vicinity, provided only that the spacecraft is outside the bow shock. However, for L1 based spacecraft, approximately an extra hour of 'prediction-time' is gained. As a test of its fidelity and consistency, the program is applied to many years of WIND data and some of the results are presented. Bothmer and Rust, in Coronal Mass Ejections, AGU Geophys. Monog. Ser, vol. 99, p 139, Washington DC., 1997.
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 7513 Coronal mass ejections
DE: 7524 Magnetic fields
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting