Influence of the solar wind high-speed streams on the thermospheric neutral density during the declining phase of solar cycle 23. Issue 12 (15th June 2022)

• Record Type: Journal Article
• Authors: Verbanac, Giuliana; Bandić, Mario; Krauss, Sandro
• Is Part Of: Advances in space research. Volume 69:Issue 12(2022)
• Page Start: 4335
• Page End: 4350
• Publication Date: 2022-06-15
• Subjects: Thermospheric neutral density -- High speed solar wind streams -- Geomagnetic activity; Space sciences -- Periodicals; Astronautics -- Periodicals; Geophysics -- Periodicals; 500.505
• DOI: 10.1016/j.asr.2022.03.032
• Languages: English
• ISSNs: 0273-1177

Abstract

Abstract: Thermospheric neutral density derived from the GRACE A satellite and normalized at altitude of 490 km ( ρ ) are used to investigate the ρ behavior during the period of recurrent geomagnetic activity (25 January - 5 May, 2005) caused by solar wind high-speed streams (HSSs). The north and south hemispheric ρ values divided in three latitudinal bins are analyzed separately at dayside and nightside. The variations, not caused by solar/geomagnetic activity, are investigated accounting for the relationship between solar flux index, illumination, latitude and DOY for particular magnetic local times (MLTs). Analysis has shown that: ρ increases/decreases from high to low latitudes at dayside/nightside; ρ increases from high to low latitudes at dayside caused by solar EUV radiation is most prominent around MLT = 14 and decrease rapidly with departure from this MLT; the difference between north and south hemispheric ρ values are not the same prior and after the equinox; quiet time ρ differs among latitudinal bins; ρ contains a clear imprint of solar/geomagnetic activity. The cross-correlation analysis reveals a high degree of correlation between ρ and different employed ρ indicators. Time lags based on all ρ indicators suggest that ρ disturbance: occurs about 4 h earlier at high than at lower latitudes and propagates presumably without losses toward equatorial region both at dayside and nightside; propagates faster between polar and mid latitudes at dayside and between mid and low latitudes at nightside. This study provides the most probable characteristics of the ρ variations during the periods in which magnetospheric-thermospheric system is affected primarily by HSSs.