The trough model

A complete three dimensional formulation for the main trough has been constructed on the basis of Dynamic Explorer (DE) data. The model uses the trough minimum model published by Werner and Prolss (which is also based on DE data) and a time dependent shape of the trough. The shape parameters — depth of the trough — equatorward half-width — poleward half-width — steepness of the equatorward wall — steepness of the poleward wall have been derived from Dynamic Explorer electron densities gained in the height region below 700 km and scaled to the F2 layer peak by means of the COSTprof model. Our trough model uses the medians of the shape parameters for three seasons (winter, equinox, summer) and two magnetic local time intervals (“day” and “night”).