You can use minus values for west longitude or south latitude. The field values, in both HDZ and XYZ field component directions, can be given in Universal Time or Local Meridian Time. It also shows how the shape of the Dst index, during geomagnetic storms, can be fitted to a log-normal distribution curve. This symmetry allows a prediction of recovery from the rise to maximum. The program computes the field decay phase of a geomagnetic storm from the hourly values.
Computations are from the start of the main phase until one hour past the peak value.
Screen graphics shows the comparison between the predicted recovery and the observed values. Try one of the sample Dst storms first to see how the program works. Ten sample data files accompanied this program on diskette. The program will prompt for the disk directory where these files are located. The projection technique requires values up to an hour past the peak of the storm.