نتایج جستجو برای: geomagnetic field
تعداد نتایج: 790640 فیلتر نتایج به سال:
[1] Geomagnetic excursions are short-lived episodes when Earth’s magnetic field deviates into an intermediate polarity state. Understanding the origin, frequency, amplitude, duration, and field behavior associated with excursions is a forefront research area within solid earth geophysics. Recent advances in excursion research are summarized here, and key further research is suggested to resolve...
Recently, many novel concepts originated in dynamical systems or information theory have been developed, partly motivated by specific research questions linked to geosciences, and found a variety of different applications. This continuously extending toolbox of non-linear time series analysis highlights the importance of the dynamical complexity to understand the behavior of the complex Earth’s...
The cosmogenic radionuclide 10Be is produced by cosmic-ray spallation in Earth’s atmosphere. Its production rate is regulated by the geomagnetic field intensity, so that its accumulation rate in aeolian sediments can, in principle, be used to derive high-resolution records of geomagnetic field changes. However, 10Be atmospheric fallout rate also varies locally depending on rainfall rate. The ac...
We conduct an analysis of the geomagnetic field variations recorded at the new Antarctic station Dome C, located very close to the geomagnetic pole, which has been operating for approximately one month during the 1999–2000 campaign. We also perform a comparison with simultaneous measurements at the Italian Antarctic station Terra Nova Bay, in order to investigate the spatial extension of the ph...
In the final phase of their spawning migration, Pacific salmon use chemical cues to identify their home river, but how they navigate from the open ocean to the correct coastal area has remained enigmatic. To test the hypothesis that salmon imprint on the magnetic field that exists where they first enter the sea and later seek the same field upon return, we analyzed a 56-year fisheries data set ...
The geomagnetic lunax daily variation field, L, was studied using all available results of lunar analysis of geomagnetic data from a total of 37 stations. Equivalent external (overhead) and internal (induced within the earth) electric current systems responsible for L variations with respect to dip latitude were estimated by the method of spherical harmonic analysis for each season. The externa...
The Dst index is a key parameter which characterises the disturbance of the geomagnetic field in magnetic storms. Modelling of the Dst index is thus very important for the analysis of the geomagnetic field. A data-based modelling approach, aimed at obtaining efficient models based on limited inputoutput observational data, provides a powerful tool for analysing and forecasting geomagnetic activ...
The effects of geomagnetic disturbances on urinary excretion of the melatonin metabolite, 6-hydroxymelatonin sulfate (6-OHMS), were studied in conjunction with 60 Hz magnetic field (MF) and ambient light exposure in 132 electric utility workers. Geomagnetic activity was assessed using a local (equivalent amplitude or A(K), Boulder, CO) and global (average antipodal or aa) index. Personal exposu...
Assimilation of surface geomagnetic observations and geodynamo models has advanced very quickly in recent years. However, compared to advanced data assimilation systems in meteorology, geomagnetic data assimilation (GDAS) is still in an early stage. Among many challenges ranging from data to models is the disparity between the short observation records and the long time scales of the core dynam...
The South Atlantic Anomaly is nowadays one of the most important features of the Earth’s magnetic field. Its extent area at the Earth’s surface is continuously growing since the intensity instrumental measurements are available covering part of the Southern Hemisphere and centered in South America. Several studies associate this anomaly as an indicator of an upcoming geomagnetic transition, suc...
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