Validation of the Parameterized Real-Time Ionospheric Specification Model (PRISM) Version 1.6B Using Topex Total Electron Content (TEC) Data

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Document Type


Degree Name

Master of Science


Department of Engineering Physics

First Advisor

Derrill T. Goldizen, PhD


The ability of the most recent version of PRISM (1.6b) to accurately specify real-time TEC values was validated against 'ground truth' TEC data obtained by the Ocean TOPography EXperiment (TOPEX). PRISM 'driver' data came from two sources: the ground-based Digital Ionospheric Sounding System (DISS - critical frequencies and layer heights) and the International Global Positioning System (GPS) Service for Geodynamics (IGS OPS - TEC values). The TEC 'ground truth' data were obtained by the NASA dual-frequency radar altimeter on-board the TOPEX satellite during 1995. 950 TEC estimates obtained from PRISM 1.6b were compared with corresponding values observed by the TOPEX satellite along multiple orbital tracks. Comparison points were chosen to be representative of different seasons (Equinox, Summer, and Winter), local times (0000L, 0600L, 1200L, and 1800L), and latitudes (30°N and equatorial). The results of PRISM-TOPEX chi-square goodness-of-fit calculations are presented to quantify the accuracy of PRISM across seasons, local times, latitudes, and varying subsets of input data.

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