secular variation
Polynomial modelling of CHAMP satellite data to investigate rapid secular variation fluctuations over southern Africa during 2003 and 2004
... annual secular variation field models for the interval 2001–2005 was done by focusing on January and December months in each year according to method ...annual secular variation field val- ues ...
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Prediction of geomagnetic field with data assimilation: a candidate secular variation model for IGRF 11
... Of the near-Earth measured geomagnetic signals, 97% (in terms of the magnetic energy) are of the internal origin (e.g. Langel and Hinze, 1998). This part of the field, called the core field, is generated and maintained by ...
11
A candidate secular variation model for IGRF 12 based on Swarm data and inverse geodynamo modelling
... unmodelled secular variation arising from the interac- tion of the small-scale magnetic field with the large-scale flow (Eymin and Hulot 2005), the robustness of the results reported here should ...
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Using geomagnetic secular variation to separate remanent and induced sources of the crustal magnetic field
... We have failed to obtain a satisfactory separation between induced and remanent parts, but we have made a convincing case for substantial induced magnetization around almost all the good observatories. Separation of ...
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SECULAR VARIATION AND PHYSICAL CHARACTERISTICS
... Thirteen new times of maximum have been gathered for the HADS star EH Lib from two observatories with CCD and uvby − β photometry. From the uvby − β data, physical parameters were determined and were utilized to obtain ...
13
Deriving main field and secular variation models from synthetic Swarm satellite and observatory data
... portunity to estimate the constant part of the geomagnetic field up to degree 17. Using a better statistical treatment of the data errors and a slightly more complex field model, we have achieved a significant improvement ...
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Toward a better representation of the secular variation Case study: The European network of geomagnetic observatories
... the secular variation using these ...a variation of about −4 nT/year would be added to the variation of the internal field, significantly altering the values and the pattern of the corresponding ...
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Shift of the mean magnetic field values: Effect of scatter due to secular variation and errors
... We have quantitatively evaluated the effect of geomag- netic secular variation and measurement errors on the mean directions. If the measurement errors are not systematic, i.e., truly random and isotopic, ...
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Improvement of the secular variation curve of the geomagnetic field in Egypt during the last 6000 years
... the secular variation of the geo- magnetic field in Egypt during this period ...the secular variation curve of the geomagnetic field in Egypt for the last 6000 years based on the ...
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Recent geomagnetic secular variation from Swarm and ground observatories as estimated in the CHAOS 6 geomagnetic field model
... Annual differences of revised observatory monthly means (Olsen et al. 2014) between January 1997 and December 2015 provide crucial constraints on the SV at fixed points on the Earth’s surface. Revised monthly means were ...
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Spatial temporal modeling of the geomagnetic field for 1980–2000 period and a candidate IGRF secular variation model for 2000–2005
... A new generation of the IZMST series (STM—space-time models based on data from observatories, POGS and Ørsted) was developed as a model of the main geomagnetic field from 1980.0 up to 2000.0. A set of the natural ...
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Main field and secular variation candidate models for the 12th IGRF generation after 10 months of Swarm measurements
... The two models are relatively similar for the static part, and only the time-varying part is different. The analysis of this difference lead us to chose the V-ASM parent model of our MF and SV candidates for IGRF. We ...
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An IGRF candidate main geomagnetic field model for epoch 2000 and a secular variation model for 2000–2005
... The secular variation models would be improved if the data series were available from more ...the secular variation depends heavily on observatory data, it will remain ...
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Secular variation and reversals in a composite 2 5 km thick lava section in central Western Iceland
... Paleomagnetic direction vectors from the 367 lavas sam- pled in this study are distributed in a similar way as those from comparable paleomagnetic collections already inves- tigated from the Neogene lava pile of Iceland. ...
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Rock magnetic changes with reduction diagenesis in Japan Sea sediments and preservation of geomagnetic secular variation in inclination during the last 30,000 years
... The higher contents of organic carbon and total sulfur be- tween 2.0 and 1.3 m, which probably caused the magnetic- mineral dissolution, indicate higher biological productivity in this interval. Its age, from about 10 to ...
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On the possibility of extending the IGRF predictive secular variation model to a higher SH degree
... predictive secular variation models would mainly be in rel- ative terms per degree of the field, and would not compen- sate for the absolute errors entailed by the uncertainties with which this ...
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Geomagnetic secular variation violating the frozen flux condition at the core surface
... geomagnetic secular variation (SV) model that is not consistent with a frozen-flux ...the secular decrease of the axial dipole has to be largely ...
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Dynamic responses of the Earth’s outer core to assimilation of observed geomagnetic secular variation
... geomagnetic secular variation (SV), described by the first-order time derivative g ˙ l m , h ˙ m l of the Gauss coefficients since, as we will describe in the next section, they provide additional ...
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Secular variation of the Earth’s magnetic field in the South West Pacific
... Regarding those differences between VADM’s from different continents it is worth mentioning that by calculating an average value over 500 years it is not possible to cancel out the secular variation, ...
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Westward drift in secular variation of the main geomagnetic field inferred from IGRF
... Different authors have their own work basis. Bullard et al. (1950) separated the drift rates of the dipole and non-dipole parts of the geomagnetic field, Malin (1969) determined the drift rate separately for each order ...
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