trend

- 3

Trapped Radiation ENvironment model Development

TREND-3

A number of new radiation belt models have been developed based on data from the following satellite experiments: AZUR/EI-88, SAMPEX/PET, UARS/PEM, CRRES/MEA, and ISEE/WIM. For each experiment, the mission and instrument characteristics and the data base formats have been described in detail in the Technical Notes of the project, and are summarised in this Final Report. The data binning procedures and the formats and limitations of the new models are described as well. The models have been intercompared where applicable, and have been compared to the standard NASA models AP-8 and AE-8. All new models have been implemented in the software package UNIRAD.

Besides the models developed in the framework of TREND-3, the ESA-SEE1 (Vampola 1996) model and the CRRESPRO (Meffert & Gussenhoven 1994) and CRRESELE (Brautigam & Bell 1995) models have also been adapted to and integrated in UNIRAD.

A large effort has been devoted to the development of a comprehensive Fortran subroutine library, called UNILIB, with the following functionalities: calculation of magnetic coordinates (e.g. B, L) and adiabatic invariants, coordinate transformations, field line and drift shell tracing, and averages of the atmospheric and ionospheric density over drift shells. The library is extensively documented on the World-Wide Web.

An extensive study has been made of the anisotropy of the low altitude trapped proton flux. After a review of the literature, one of the most commonly used models has been implemented in UNIRAD, together with an improved version. In addition, a method has been developed to render the anisotropy effects in terms of a natural coordinate system attached to the magnetic field. The method has been validated with the SAMPEX/PET data base.

Appropriate analytical functions have been found to fit the pitch angle distributions measured by CRRES/MEA. Finally, a new, corrected, Meteosat-3/SEM-2 data base has been produced.

Project made under ESA/Contract No. 10725/94/NL/JG(SC) and No. 11711/95/NL/JG(SC) WO-3