A numerical data base for VAX and personal computers for the storage, reconstruction and display of global thermospheric and ionospheric models

Abstract

Theoretical three-dimensional and time-dependent atmospheric models (also called General Circulation Models) describe, in a forward simulation fashion, the response of the atmosphere to complex external driving forces. Their advent has created a need to disseminate the large volume of data presented by such models to potential users in a convenient and abbreviated form. Taking as an example the theoretical thermospheric model developed at University College London, England, it is inconvenient to transmit the data by print-out, magnetic tape, disk media, electronic mail or networks. The number of individual parameters computed in a data set corresponding to a “steady-state” 24 h simulation, contains 3.8 × 10 6 real numbers, describing 15 pressure levels, 91 steps in latitude, 20 steps in longitude, 20 steps in Universal Time, and at least seven geophysical (atmospheric) parameters. These large numerical data sets exist for each of some 50 complete thermospheric simulations, covering a range of solar, geomagnetic and seasonal conditions. A process of high energy Fourier filtering has been used to reduce the data volume by a factor of up to 150, a data set size which is convenient for storage and electronic transmission purposes. A four-dimensional array, i.e. latitude vs longitude vs height vs time, can be quickly and conveniently reconstructed with high fidelity, for each individual atmospheric parameter using a VAX or PC computer. This provides a convenient and rapid means of disseminating verified data from the global simulations to end users.