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

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. Plain Language Summary: This contribution presents the findings of an investigation about the Weddell Sea Anomaly, an intriguing ionospheric phenomenon occurring between South America and Antarctica during December. Despite the several decades since the initial reports, the Weddell Sea Anomaly remains a topic of scientific research. The study is based on a novel self‐developed technique to produce global ionospheric maps using TEC measurements from satellite altimeter missions. The results presented provide support for the hypothesis that the Weddell Sea Anomaly may be connected to the Equatorial Ionospheric Anomaly. Furthermore, our findings indicate that the Equatorial Ionospheric Anomaly also displays anomalous behavior over the entire southern hemisphere, with the Weddell Sea Anomaly as the most contrasting of them. We also demonstrate the significant correlation that exists between the Equatorial Ionospheric Anomaly regions and the Y component of the geomagnetic field in relation to the WSA. We then present a possible hypothesis for interpreting these results. Key Points: The study of the Weddell Sea Anomaly with ULIC maps provides a new conceptual framework supporting and extending published theoriesThe new framework considers the anomaly as a mark of a more complex phenomenon that correlates significantly with the geomagnetic fieldThe manuscript presents an innovative technique for producing TEC maps that are suitable to study the climatology of the ionosphere [ABSTRACT FROM AUTHOR]