In the present paper dependence of geomagnetic activity on the solar-wind plasma and interplanetary magnetic field (IMF) parameters has been studied. We have taken interplanetary solar wind data at the instant of Dst ...In the present paper dependence of geomagnetic activity on the solar-wind plasma and interplanetary magnetic field (IMF) parameters has been studied. We have taken interplanetary solar wind data at the instant of Dst minimum. Our study consists of 200 geomagnetic storms weighed by disturbance storm time (Dst) -50 nT, observed during solar cycle 23. The study suggests that the strength of the geomagnetic storm is strongly dependent on the total magnetic field Btotal. The correlation (-0.72) has been found reasonable. In perspective of previous studies, the strength of the geomagnetic storm is strongly dependent on the southward component (Bz) whereas in present study exposes that the correlation (0.22) is weak. This result indicates that solar wind southward magnetic field component Bz has significant growth particularly before the main phase of geomagnetic storm (not during the main phase). The present result implies that neither density nor temperature is significantly related to the variation of geomagnetic disturbance;rather the effects of the pressure and speed. However, a low plasma beta during highly geoeffective event seems to be an important criterion.展开更多
Based on the measurements made by Atmospheric Density Detectors(ADDs) onboard Chinese spacecraft Shenzhou 2-4,the variations of thermosphere density are revealed.During the quiet period,the density at spacecraft altit...Based on the measurements made by Atmospheric Density Detectors(ADDs) onboard Chinese spacecraft Shenzhou 2-4,the variations of thermosphere density are revealed.During the quiet period,the density at spacecraft altitude of 330~410 km exhibited a dominant diurnal variation,with high value on dayside and low value on nightside.The ratio of the diurnal maximum density to the minimum ranged from 1.7 to 2.0.The ratio shows a positive correlation with the level of solar activity and a negative correlation with the level of geomagnetic activity.When a geomagnetic disturbance comes,the atmospheric density at the altitude of 330～410 km displayed a global enhancement.For a strong geomagnetic disturbance,the atmospheric density increased by about 56%,and reached its maximum about 6～7 hours after the geomagnetic disturbance peak. The density asymmetry was also observed both in the southern and northern hemisphere during the geomagnetic disturbance peak.展开更多
This study examines the relationship between geomagnetic indices and mortality rates from specific diseases in the Northeast (NE) and Southern (S) regions of Brazil from 1996 to 2020. Solar activity data, including th...This study examines the relationship between geomagnetic indices and mortality rates from specific diseases in the Northeast (NE) and Southern (S) regions of Brazil from 1996 to 2020. Solar activity data, including the Ap and Sudden Ionospheric Disturbance (SID) indices, were sourced from the World Data Center, while mortality data were obtained from the Mortality Information System (SIM-DATASUS). Acute Myocardial Infarction (AMI) emerged as the leading cause of mortality, with average death rates of 60.4, 56.8, and 58.3 deaths per 100,000 inhabitants in Pernambuco (PE), Rio Grande do Sul (RS), and Paraná (PR), respectively. Temporal analysis revealed a consistent upward trend in AMI mortality across most states, except for Santa Catarina (SC). Seasonal patterns identified through Principal Component Analysis (PCA) demonstrated that geomagnetic and climatic indices influenced mortality differently across regions and seasons. The Ap geomagnetic index was strongly correlated with higher AMI mortality rates during summer, while the SID index showed greater relevance during winter. A dipole phenomenon was observed, with AMI deaths increasing alongside geomagnetic activity in the S region but showing an inverse relationship in the NE region. These findings highlight the significant influence of geomagnetic variations on public health, particularly cardiovascular mortality. The study underscores the need for further research into the biological mechanisms underlying these associations and recommends the development of early warning systems and targeted preventive measures to mitigate the potential health impacts of geomagnetic disturbances, especially for vulnerable populations.展开更多
文摘In the present paper dependence of geomagnetic activity on the solar-wind plasma and interplanetary magnetic field (IMF) parameters has been studied. We have taken interplanetary solar wind data at the instant of Dst minimum. Our study consists of 200 geomagnetic storms weighed by disturbance storm time (Dst) -50 nT, observed during solar cycle 23. The study suggests that the strength of the geomagnetic storm is strongly dependent on the total magnetic field Btotal. The correlation (-0.72) has been found reasonable. In perspective of previous studies, the strength of the geomagnetic storm is strongly dependent on the southward component (Bz) whereas in present study exposes that the correlation (0.22) is weak. This result indicates that solar wind southward magnetic field component Bz has significant growth particularly before the main phase of geomagnetic storm (not during the main phase). The present result implies that neither density nor temperature is significantly related to the variation of geomagnetic disturbance;rather the effects of the pressure and speed. However, a low plasma beta during highly geoeffective event seems to be an important criterion.
文摘Based on the measurements made by Atmospheric Density Detectors(ADDs) onboard Chinese spacecraft Shenzhou 2-4,the variations of thermosphere density are revealed.During the quiet period,the density at spacecraft altitude of 330~410 km exhibited a dominant diurnal variation,with high value on dayside and low value on nightside.The ratio of the diurnal maximum density to the minimum ranged from 1.7 to 2.0.The ratio shows a positive correlation with the level of solar activity and a negative correlation with the level of geomagnetic activity.When a geomagnetic disturbance comes,the atmospheric density at the altitude of 330～410 km displayed a global enhancement.For a strong geomagnetic disturbance,the atmospheric density increased by about 56%,and reached its maximum about 6～7 hours after the geomagnetic disturbance peak. The density asymmetry was also observed both in the southern and northern hemisphere during the geomagnetic disturbance peak.
文摘This study examines the relationship between geomagnetic indices and mortality rates from specific diseases in the Northeast (NE) and Southern (S) regions of Brazil from 1996 to 2020. Solar activity data, including the Ap and Sudden Ionospheric Disturbance (SID) indices, were sourced from the World Data Center, while mortality data were obtained from the Mortality Information System (SIM-DATASUS). Acute Myocardial Infarction (AMI) emerged as the leading cause of mortality, with average death rates of 60.4, 56.8, and 58.3 deaths per 100,000 inhabitants in Pernambuco (PE), Rio Grande do Sul (RS), and Paraná (PR), respectively. Temporal analysis revealed a consistent upward trend in AMI mortality across most states, except for Santa Catarina (SC). Seasonal patterns identified through Principal Component Analysis (PCA) demonstrated that geomagnetic and climatic indices influenced mortality differently across regions and seasons. The Ap geomagnetic index was strongly correlated with higher AMI mortality rates during summer, while the SID index showed greater relevance during winter. A dipole phenomenon was observed, with AMI deaths increasing alongside geomagnetic activity in the S region but showing an inverse relationship in the NE region. These findings highlight the significant influence of geomagnetic variations on public health, particularly cardiovascular mortality. The study underscores the need for further research into the biological mechanisms underlying these associations and recommends the development of early warning systems and targeted preventive measures to mitigate the potential health impacts of geomagnetic disturbances, especially for vulnerable populations.
