HR: 17:30h
AN: SA22C-07    [PDF]
TI: Predicting Equatorial Spread-F with First-Principles Ionospheric Models
AU: * Retterer, J M
EM: retterer@plh.af.mil
AF: Air Force Research Lab., AFRL/VSBXP 29 Randolph Rd, Hanscom AFB, MA 01731
AB: The generation of radio scintillation in the equatorial ionosphere involves physical processes acting on scales from the global down to the sub-kilometer. In preparation for the launch of the Communication and Navigation Outage Forecast System (C/NOFS) satellite, our laboratory has been developing a system of first-principles ionospheric/thermospheric models to predict the strength of scintillation in regions affected by equatorial plasma bubbles. The forecast system begins with a specification of the current state of the ambient ionosphere by assimilation of in-situ data. From this initial state, the ambient plasma density on near-equatorial field lines is calculated in the near future, to provide the background conditions for a nonlinear model of the development of plasma structures on mesoscales (1-1000 km), in a nested-grid description. To estimate the strength of scintillation, the statistical properties of the mesoscale turbulence are then extrapolated down to the scales where plasma density irregularities affect radio propagation. After describing this forecast system, I will present case-study runs of the models driven by assimilating plasma velocity data from the ROCSAT satellite. Comparisons of the computed plasma density along the satellite track will then be made with in-situ measurements. Similarly, comparisons of in-situ plasma density irregularities will be made with the locations of scintillation predicted by the model. These studies are part of a validation campaign for the forecast models prior to launch of the C/NOFS satellite.
DE: 2411 Electric fields (2712)
DE: 2415 Equatorial ionosphere
DE: 2437 Ionospheric dynamics
DE: 2439 Ionospheric irregularities
DE: 2447 Modeling and forecasting
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting