Date of Award

3-2001

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Devin J. Della-Rose, PhD

Abstract

Geomagnetic disturbances in the near earth space environment can adversely affect numerous military and Department of Defense (DoD) systems and operations. To improve the prediction accuracy of such disturbances, the next generation of space environment forecast models aims to automatically ingest real-time ionospheric measurements. This research validates and assesses one such measurement - the Defense Military Satellite Program (DMSP) measured electron temperature (Te). DMSP Te data were validated against near simultaneous incoherent scatter radar (ISR) Te measurements from Millstone Hill, MA and Sondrestrom, Greenland between Winter 1996 and Summer 2000. Of the 37 Millstone and six Sondrestrom conjunctions compared, DMSP Te values exceeded ISR Te values by an average of about 25 percent, which is nearly three times the mean ISR uncertainty. DMSP vs. ISR Te percent differences were smallest during solar maximum, increasing towards solar minimum, likely due to photoelectron influence on DMSP Te measurements. In some cases, instrument related anomalies produced unreliable measurements. Based on an assumed linear Te behavior at mid latitudes, the average DMSP Te random noise level above Millstone Hill was estimated at about four percent, falling well within the published Te measurement accuracy. A more comprehensive comparison extending to other sectors of the DMSP orbit is required to further validate the root cause of the DMSP Te - ISR Te offset.

AFIT Designator

AFIT-GAP-ENP-01M-03

DTIC Accession Number

ADA392676

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