نتایج جستجو برای: geomagnetic
تعداد نتایج: 6280 فیلتر نتایج به سال:
Part of results of collaborative studies for revealing an influence of the periodical changes of solar, geomagnetic and cosmic ray activities on the sudden cardiac death (SCD) mortality is described in this paper. The data covering daily and monthly temporal distribution of SCD (788 patients in 36 months in 2003-2005), taken from all of emergency and first medical aid stations of grand Baku are...
From the daily index Ap of geomagnetic activity, sequences of consecutive occurrence of Ap≤4 for four days and Ap≤7 for 8 days are identified in the period 1963-1998. A superposed epoch analysis is performed with the onset of these sequences and with eight different solar wind and IMF parameters. A systematic pattern of change from days preceding to the days following the quiet intervals is cle...
earthquakes show unknown nonlinear behavior and given the magnitude of the earthquake, we would encounter certain changes in lithosphere, atmosphere and ionosphere. the ionospheric parameters have been found to be sorely susceptible to major earthquakes. in addition to the ionospheric variations generated by solar activity, there are remarkable temporary changes in the ionosphere that are gener...
The discussion in the preceding paper is restricted to the uncertainties in magnetic-field-line tracing in the magnetosphere resulting from published standard errors in the spherical harmonic coefficients that define the axisymmetric part of the internal geomagnetic field (i.e. gn dg 0 n). Numerical estimates of these uncertainties based on an analytic equation for axisymmetric field lines are ...
A sequence of three subsequent auroral activations (at 18:10, 19:48 and 20:00 UT) on 9 February 1997 is analysed. The brightenings of optical auroras were collocated with latitudinally localized bursts of pulsating riometer absorption and Pi3 geomagnetic pulsations. In two of the cases, the strongest westward directed electrojet currents and the footpoint of the upward directed field-aligned cu...
[1] Global observations of electron density profiles from the COSMIC satellites are used to investigate, for the first time, the altitudinal dependence of the ionospheric response to the recurrent geomagnetic activity at different latitudinal regions during the extreme solar minimum period of 2008. Our results show that the 9-day oscillations in NmF2 are out of phase with those in Kp at high la...
We use polarity reversal systematics from numerical dynamos to quantify the hypothesis that the modulation of geomagnetic reversal frequency, including geomagnetic superchrons, results from changes in core heat flux related to growth and partial collapse of the two seismically-imaged lower mantle superplumes. We parameterize the reversal frequency sensitivity from numerical dynamos in terms of ...
A rotational inertial navigation system (RINS) has been wildly used in long term marine navigation. In a dual-axis RINS, with all constant biases averaged out, the errors which can not be averaged out become the main error source. In this paper, the gyro geomagnetic biases of a dual-axis RINS are modelled, analysed and calibrated. The gyro geomagnetic biases are proved unable to be averaged out...
The weakening of the geomagnetic field causes an increase in galactic cosmic ray (GCR) flux. Some researchers argue that enhanced GCR flux might lead to a climatic cooling by increasing low cloud formation, which enhances albedo (umbrella effect). Recent studies have reported geological evidence for a link between weakened geomagnetic field and climatic cooling. However, more work is needed on ...
Based on the analysis of the Vr index from data from geomagnetic observatories in China and four geomagnetic observatories abroad, temporal-spatial distribution characteristics of Vr index were analyzed. The Vr index showed 27-day solar-cycle recurrences and significant seasonal variation. It also increased with latitude. Meanwhile, both local-time dependence and an obvious dusk-dawn asymmetry ...
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