Study of the Weddell Sea Anomaly Using Novel Satellite Altimeter TEC Maps

Abstract

The Weddell Sea Anomaly (WSA) is a phenomenon of unique intensity and geographic extent that occurs in December (Southern Hemisphere summer) over the southeastern Pacific and southwestern Atlantic oceans regions. Historically, the classic definition of the WSA refers to a situation in which the midnight NmF2 (or TEC) values are greater than the noon NmF2 (or TEC) values. However, several articles published in the last decades have shown that the WSA is a much more complex phenomenon, and its definition might need to be reformulated. This paper presents a phenomenological description of the WSA using a novel type of vertical Total Electron Content (TEC) maps, obtained from altimeter satellite TEC data. The focus of this study is on the possible connection between the WSA and the unexpected expansion and contraction periods observed on the Equatorial Ionospheric Anomaly (EIA) throughout the Southern Hemisphere. The data analysis revealed that the WSA is only one of a number of observed anomalies. Furthermore, we show a significant correlation between the behavior of the EIA and the Y component of the geomagnetic field, which maximizes in the WSA region. We then present a possible hypothesis for interpreting these results.