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Variability of geomagnetic field at Langkawi, south-east asia during the ascending phase of solar cycle 24.

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Title: Variability of geomagnetic field at Langkawi, south-east asia during the ascending phase of solar cycle 24.
Authors: Abbas, Mustapha1 mapjysik@yahoo.com, Koko, Arzika Yusuf1,2, Mohammad, Mukhtar3, Furfuri, Mukhtar Ibrahim1,4, Muhammad, Aminu1, Audu, Asabe Ibrahim3, Kaoje, Mohammed Bello1
Source: Latin-American Journal of Physics Education. Dec2025, Vol. 19 Issue 4, p1-8. 8p.
Subject Terms: Geomagnetic variations, Solar cycle, Ionospheric electron density, Solar activity, Diurnal variations in meteorology, Equatorial electrojet, Magnetic storms
Geographic Terms: Langkawi Island (Kedah, Malaysia), Southeast Asia
Abstract (English): The magnetic records obtained at low latitude geomagnetic observatory of Langkawi for the period of 3 years was used to study the diurnal and monthly-mean variation of the horizontal, H, and vertical, Z, geomagnetic field intensities during quiet and disturbed conditions. Results revealed that quiet SqH and SqZ with their corresponding disturbed variations (SdH and SdZ) shows minimum values at nighttime (19:00-05:00) LT hrs that are lower than the pre-sunrise (06:00-07:00) LT hrs. On quiet conditions, the SqH shows remarkable daytime linear increase from 155 nT in 2011 to 160 and 162 nT in 2012 and 2013. The disturbed period exhibit irregular variation trend with highest values 227, 215 and 237 nT in 2011, 2012 and 2013 respectively. The daytime maximum MSqH values increase from ~125 nT in 2011 to 135 nT in October 2013, in contrast to MSdH that decrease progressively from 166 nT in September 2011 to 145 nT in March 2013. The reduced MSdH magnitude with increasing solar activity seems to indicate weakening effect of the disturbance dynamo dynamo mechanism. The daytime maximum SqZ and SdZ with their monthly-mean (MSqH and MSdH) readily conform to those amplitudes variation pattern with lesser magnitudes. The daytime SqH maximum with their MSqH were observe to occur around (10:00-12:00) LT hrs and shifted to 14:00 LT during disturbed period indication of possible modification of equatorial electrojet during disturbed period. The greater seasonal SSqH magnitude at the equinoctial season may likely be due to the fact that the sun is directly towards the equator around this season. The increase in AsqH and ASdH with solar activity can be likened to the effect of solar activity on the ionospheric conductivity. [ABSTRACT FROM AUTHOR]
Abstract (Portuguese): Los registros magnéticos obtenidos en el observatorio geomagnético de baja latitud de Langkawi durante un período de 3 años se utilizaron para estudiar la variación media diurna y mensual de las intensidades del campo geomagnético horizontal (H) y vertical (Z) en condiciones tranquilas y perturbadas. Los resultados revelaron que las SqH y SqZ en condiciones tranquilas, con sus correspondientes variaciones perturbadas (SdH y SdZ), muestran valores mínimos durante la noche (19:00-05:00) horas de luz solar, inferiores a los valores de la hora de luz solar antes del amanecer (06:00-07:00). En condiciones tranquilas, el SqH muestra un notable aumento lineal diurno de 155 nT en 2011 a 160 y 162 nT en 2012 y 2013. El período perturbado exhibe una tendencia de variación irregular con los valores más altos de 227, 215 y 237 nT en 2011, 2012 y 2013 respectivamente. Los valores máximos diurnos de MSqH aumentan de ~125 nT en 2011 a 135 nT en octubre de 2013, en contraste con MSdH que disminuye progresivamente de 166 nT en septiembre de 2011 a 145 nT en marzo de 2013. La magnitud reducida de MSdH con el aumento de la actividad solar parece indicar un efecto de debilitamiento del mecanismo dinamodinamo de perturbación. Los máximos diurnos de SqZ y SdZ, con sus medias mensuales (MSqH y MSdH), se ajustan fácilmente a estos patrones de variación de amplitud con magnitudes menores. Se observó que el máximo diurno de SqH con su MSqH se produjo alrededor de las 10:00-12:00 horas locales (LT) y se desplazó a las 14:00 horas locales (LT) durante el período de perturbación, lo que indica una posible modificación del electrochorro ecuatorial durante dicho período. La mayor magnitud estacional de SSqH en la estación equinoccial probablemente se deba a que el sol se encuentra directamente hacia el ecuador en esta estación. El aumento de AsqH y ASdH con la actividad solar puede compararse con el efecto de la actividad solar en la conductividad ionosférica. [ABSTRACT FROM AUTHOR]
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Database: Education Research Complete
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Abstract:The magnetic records obtained at low latitude geomagnetic observatory of Langkawi for the period of 3 years was used to study the diurnal and monthly-mean variation of the horizontal, H, and vertical, Z, geomagnetic field intensities during quiet and disturbed conditions. Results revealed that quiet SqH and SqZ with their corresponding disturbed variations (SdH and SdZ) shows minimum values at nighttime (19:00-05:00) LT hrs that are lower than the pre-sunrise (06:00-07:00) LT hrs. On quiet conditions, the SqH shows remarkable daytime linear increase from 155 nT in 2011 to 160 and 162 nT in 2012 and 2013. The disturbed period exhibit irregular variation trend with highest values 227, 215 and 237 nT in 2011, 2012 and 2013 respectively. The daytime maximum MSqH values increase from ~125 nT in 2011 to 135 nT in October 2013, in contrast to MSdH that decrease progressively from 166 nT in September 2011 to 145 nT in March 2013. The reduced MSdH magnitude with increasing solar activity seems to indicate weakening effect of the disturbance dynamo dynamo mechanism. The daytime maximum SqZ and SdZ with their monthly-mean (MSqH and MSdH) readily conform to those amplitudes variation pattern with lesser magnitudes. The daytime SqH maximum with their MSqH were observe to occur around (10:00-12:00) LT hrs and shifted to 14:00 LT during disturbed period indication of possible modification of equatorial electrojet during disturbed period. The greater seasonal SSqH magnitude at the equinoctial season may likely be due to the fact that the sun is directly towards the equator around this season. The increase in AsqH and ASdH with solar activity can be likened to the effect of solar activity on the ionospheric conductivity. [ABSTRACT FROM AUTHOR]
ISSN:18709095