HR: 09:20h
AN: SA11B-06    [Abstracts]
TI: IDA4D – a new ionospheric imaging algorithm using non-linear ground-based and spaced- based data sources
AU: * Bust, G
EM: gbust@astraspace.net
AF: ASTRA, Atmospheric & Space Technology Research Associates 11118 Quail Pass, San Antonio, TX 78249, United States
AU: Crowley, G
EM: gcrowley@astraspace.net
AF: ASTRA, Atmospheric & Space Technology Research Associates 11118 Quail Pass, San Antonio, TX 78249, United States
AU: Curtis, N
EM: ncurtis@astraspace.net
AF: ASTRA, Atmospheric & Space Technology Research Associates 11118 Quail Pass, San Antonio, TX 78249, United States
AU: Reynolds, A
EM: areynolds@astraspace.net
AF: ASTRA, Atmospheric & Space Technology Research Associates 11118 Quail Pass, San Antonio, TX 78249, United States
AU: Paxton, L
EM: larry.paxton@jhuapl.edu
AF: JHU/APL, Applied Physics Laboratory 11100 Johns Hopkins Rd Laurel, MD 20723, Laurel, MD 20723, United States
AU: Coker, C
EM: clayton.coker@nrl.navy.mil
AF: NRL, US Naval Research Lab 4555 Overlook Ave., SW Code 7669, Washington, DC 20375, United States
AU: Bernhardt, P
EM: paul.bernhardt@nrl.navy.mil
AF: NRL, US Naval Research Lab 4555 Overlook AVe., SW Code 6750, Washington, DC 20375, United States
AB: New data assimilative methods combining ground and spaced-based ionospheric data are used to investigate the dynamics of the mid and low-latitude ionosphere. Data sources that are both linearly and non-linearly related to electron density can for the first time be ingested into the four-dimensional (4D) ionospheric imaging algorithm "Ionospheric Data Assimilation Four Dimensional" (IDA4D). This innovative step to use nonlinear data sources allows previously unused ionospheric data to be included in a data assimilation process that now takes in nine types of measurements to produce highly accurate ionospheric maps on a global scale, with formal error estimates. IDA has been in development for over 15 years, and is a mature, well validated algorithm that has been used for a number of scientific investigations. In the last year the IDA algorithm has been improved in two ways. First, IDA now solves for the log of electron density in a non-linear iterative method. This assures that the electron density is positive definite. Second, the algorithm uses high-latitude drift velocities obtained from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) algorithm in a high-latitude forward prediction model. This provides a much improved capability for imaging high-latitude plasma structures. In addition to algorithm improvements, several new data sources have been added to IDA. The addition of the non-linear methodology has allowed the ingestion of non-linear data sources. These include time delay versus frequency obtained from ionosondes, EUV data from the GUVI sensor on the TIMED satellite and the TIP sensor on COSMIC. In addition, the other data sources on COSMIC including occultations and Tri-band beacon data are routinely ingested by IDA4D. Finally, new linear data sources that are now ingested by IDA4D include data from the DORIS array and CITRIS receiver. The new IDA4D algorithm is used to investigate the ionospheric system response to magnetic storms. Images of electron density are presented for several recent magnetic storms. The relationship between the observed ionospheric structures and the underlying physical mechanisms that cause them is discussed. Also discussed are innovative methods that investigate the relative importance of the underlying physical processes using the new algorithm in ways that were previously not possible.
DE: 2415 Equatorial ionosphere
DE: 2447 Modeling and forecasting
DE: 2494 Instruments and techniques
DE: 6982 Tomography and imaging (7270, 8180)
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting