Naslov
Influence of the solar wind high-speed streams on the thermospheric neutral density during the declining phase of solar cycle 23

Autori
Verbanac, Giuliana ; Bandić, Mario ; Krauss, Sandro

Izvornik
Advances in space research (0273-1177) 69 (2022); 4335-4350

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Thermospheric neutral density ; High speed solar wind streams ; Geomagnetic activity

Sažetak
Thermospheric neutral density derived from the GRACE A satellite and normalized at altitude of 490 km (rho) are used to investigate the rho 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 rho 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: rho increases/decreases from high to low latitudes at dayside/nightside ; rho 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 rho values are not the same prior and after the equinox ; quiet time rho differs among latitudinal bins ; rho contains a clear imprint of solar/geomagnetic activity. The cross-correlation analysis reveals a high degree of correlation between rho and different employed rho indicators. Time lags based on all rho indicators suggest that rho 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 rho variations during the periods in which magnetospheric-thermospheric system is affected primarily by HSSs.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Geofizika

POVEZANOST RADA