Longitudinal Dependence of Ionospheric Poynting Flux in the Northern Hemisphere During Quite Times

• Published in: Journal of geophysical research. Space physics 2021-10, Vol.126 (10), p.n/a
• Main Authors: Yu, Chao, Zhang, Xiao‐Xin, Wang, Wenbin, He, Fei
• Format: Article
• Language: English
• Subjects: Defense programs; DMSP satellites; Eastern Hemisphere; Fluctuations; Geographical coordinates; Geomagnetism; Magnetospheres; Meteorological satellite program; Meteorological satellites; Northern Hemisphere; Seasonal variations; Upper atmosphere; Western Hemisphere
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2021JA029717

This study reports the longitudinal dependence of the field‐aligned Poynting flux in the Northern Hemisphere (NH) based on 11 years' (1999–2009) observations at ∼800 km altitude by the Defense Meteorological Satellite Program (DMSP) F13 satellite. Seasonal variations of the longitudinal distributions of the Poynting flux in both geographic and geomagnetic coordinates were statistically investigated. The net Poynting flux, which is the sum of downward and upward fluxes, is downward and peaks in the magnetic local time pre‐noon sector and near the geomagnetic pole. In geographic coordinates there is a longitudinal peak of the net Poynting flux that occurs between ∼130° and 160°W. The net Poynting flux is, in general, stronger in the western hemisphere than in the eastern hemisphere and larger in summer than in winter. These results indicate that the magnetospheric energy deposition into the northern polar upper atmosphere has obvious longitudinal and seasonal variations. Key Points Both case and statistical studies indicate downward Poynting flux has a maximum or hotspot at high latitudes in the North American sector The downward Poynting flux hotspot is located in the 08–12 h geomagnetic local time sector in the cusp region near the northern geomagnetic pole The strength of the downward Poynting flux hotspot is the strongest in northern summer and the weakest in northern winter