Accession Number:

AD1120031

Title:

Investigation of the Causes of the Longitudinal Variation of the Electron Density in the Weddell Sea Anomaly

Descriptive Note:

Journal Article - Open Access

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States

Report Date:

2017-05-24

Pagination or Media Count:

22.0

Abstract:

This paper investigates and quantifies the causes of the Weddell Sea Anomaly WSA, a region near the tip of South America extending from approximately 30 degrees to 120 degrees W geographic longitude and 50 degrees to 75 degrees S geographic latitude at solar minimum between 2007 and 2010. This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer. This study is far more quantitative than previous studies because, unlike other models, it assimilates selected data parameters to constrain a physical model in order to investigate other aspects of the data. It is shown that the commonly accepted explanation that the WSA is related to the magnetic field declination and inclination effects on the neutral wind does not explain the longitudinal variation of the electron density. Rather, longitudinal changes in the neutral winds and neutral densities are the most likely explanation for the WSA. These longitudinal wind and density changes are attributed to the varying latitudinal distance from the auroral zone energy input. No contributions from the plasmasphere or other sources are required. Furthermore, it is shown that a widely used empirical thermosphere density model overestimates the longitudinal changes in the WSA region

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE