USGS Open-File Report 2012–1167: Superposed Epoch Analysis and Storm Statistics from 25 Years of the Global Geomagnetic Disturbance Index, USGS-Dst

Superposed Epoch Analysis and Storm Statistics from 25 Years of the Global Geomagnetic Disturbance Index, USGS-Dst

By J.L. Gannon

Abstract

Statistics on geomagnetic storms with minima below -50 nanoTesla are compiled using a 25-year span of the 1-minute resolution disturbance index, U.S. Geological Survey Dst. A sudden commencement, main phase minimum, and time between the two has a magnitude of 35 nanoTesla, -100 nanoTesla, and 12 hours, respectively, at the 50th percentile level. The cumulative distribution functions for each of these features are presented. Correlation between sudden commencement magnitude and main phase magnitude is shown to be low. Small, medium, and large storm templates at the 33rd, 50th, and 90th percentile are presented and compared to real examples. In addition, the relative occurrence of rates of change in Dst are presented.

First posted August 21, 2012

Report PDF (2.88 MB)

For additional information contact:
Geologic Hazards Science Center
U.S. Geological Survey
Box 25046
Denver, CO 80225-0046
http://geohazards.cr.usgs.gov/

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Suggested citation:

Gannon, J.L., 2012, Superposed epoch analysis and storm statistics from 25 years of the global geomagnetic disturbance index, USGS-Dst: U.S. Geological Survey Open-File Report 2012–1167, 15 p.

Contents

Abstract

Introduction

Data

Statistics

“Average” Storm

Time Rate of Change of Dst

Summary

Acknowledgments

References