The Weddell sea anomaly observed with the Topex satellite data

This paper introduces the complete image of the Weddell Sea Anomaly, observed with the over-the-ocean ionospheric total electron content (TEC) values obtained from the TOPEX satellite data with an almost unlimited coverage over the oceans, the first time according to the literature; and investigates its development. With a series of TOPEX TEC maps, this paper demonstrates the diurnal variations of both the night-time and the day-time Weddell Sea Anomaly, which appeared as a night-time TEC enhancement and as a day-time TEC depletion, during the near sunspot maximum period of 1998 and 1999 investigated. Several TOPEX passes, plotted in geomagnetic latitudes, are also presented to demonstrate the longitudinal variations of the Weddell Sea Anomaly, and also to show other ionospheric features appearing such as the southern-hemisphere mid-latitude day-time and night-time trough, the northern-hemisphere mid-latitude night-time trough and the equatorial anomaly. This paper demonstrates how large the anomaly is in reality situated west of the Faraday ionosonde station over the Bellinghausen Sea and not over the Weddell Sea that is east of Faraday. Thus the correct name should be Bellinghausen Sea Anomaly. Based upon the review paper of Dudeney and Piggott (1978), the development of the Weddell Sea Anomaly is explained with the combined effects of solar ultraviolet radiation and thermospheric neutral winds. (C) 2003 Elsevier Science Ltd. All rights reserved.