Global Variations of the POGO electrojet parameters during the solstices.

Abstract

A method of analysis has been used to obtain electrojet parameters from the POGO Satellites' data during the solstitial seasons. This yields enormous values about 432 each, of electrojet's halfwidth w, peak eastward intensity J0, and total eastward current I+, -covering the entire 360° longitudes round the earth, and within 6 hours of local day time in the December and June solstitial months of the years 1968 and 1969 respectively. The daytime all-longitude averages of these parameters for the combined solstices are: (226±11)km for w, (207±28) Akm-1 for J0 and (51±7)×103 A for I+. This second coverage of the earth, with a new set of data, shows that J0 and I+ vary considerably with longitude, unlike w, which remains fairly constant throughout the globe. Interestingly, we find that, apart from the expected maximum in J0 and I+ around longitude 280°E, subsidiary maxima also occur at about 100°E, and 190°E, in confirmation of the equinoctial results of ONWUMECHILI and AGU (1981). It is suggested that the longitudinal variations in J0 and I+, may arise from the longitudinal differences in conductivities, wind systems and possibly changes in electric field at electrojet altitudes.