AN OVERVIEW OF THE 26-27 SEPTEMBER 2011 GEOMAGNETIC STORM AS
MEASURED BY GPS RECEIVERS AND SUPERDARN HF RADARS
Evan G. Thomas
Advisors: Drs. J. B. H. Baker and J. M. Ruohoniemi
Virginia Tech, Blacksburg, VA
Many critical technologies relied upon by both commercial and military users around the world
are directly impacted by events occurring in the Earth’s ionosphere. Strong geomagnetic storms
are responsible for causing ionospheric clutter in over-the-horizon radar systems; scintillations
and their associated errors in GPS signals; and induced electrical currents in power distribution
networks. Here we present an overview of a large geomagnetic storm on 26-27 September 2011
which was caused by a coronal mass ejection from the sun. During this period, the Federal
Aviation Administration (FAA) reported widespread outages in the Wide Area Augmentation
System (WAAS), which is used to aid aircraft navigation and landing throughout North America.
This research paper is a summary of the results published by Thomas et al. [2013] and Zhang et
al. [2013] on the features observed in the Earth’s ionosphere during this large geomagnetic
storm.