Deriving the effective scale height in the topside ionosphere based on ionosonde and satellite in situ observations

Abstract

Chapman scale height is a valuable key parameter measuring the shape of the profile of plasma density in the F2 layer ionosphere. Currently, the data of Chapman scale height are routinely derived from ionogram observations at many ionosonde stations in terms of the SAO explorer software. In this report, we collected the in situ observations of plasma density at altitudes around 600?km from the ROCSAT-1 satellite and of simultaneous F peak parameters from an ionosonde operated at Wuhan (30.6N, 114.4E), a low-latitude station in central China, to estimate the topside plasma density profiles by using the Chapman α function and further retrieve Chapman scale height. Evident solar cycle, seasonal variation, and local time variation are presented in the retrieved Chapman scale height over Wuhan. The climatological features of the derived Chapman scale height are significantly different from those from the ground-based ionograms. Such significant discrepancy suggests that further improvements are required in the present extrapolating topside electron density profiles from ionosonde observations. Furthermore, the attempt to constructing plasma density profiles through combining ionosonde and satellite in situ observations provides a new way to reanalyze observations from different sources and normalize plasma density recorded at varying altitudes to specified altitudes, which is critical and more convenient for ionospheric climatology studies. Key Points Retrieve topside Chapman scale height from ROCSAT-1 and ionosonde observationsEvident solar activity, season variation, and diurnal variation in Chapman scale heightNeed improvement in retrieving topside plasma density from ionogram