A normal reference field for the Ionian sea area

Chiappini, M.; Santis, A. De; Dominici, G.; Torta, J. M.

doi:10.1016/s1464-1895(99)00071-x

Cited by 5 publications

(4 citation statements)

References 7 publications

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“…The older dataset of magnetic measurements used here is the total intensity F measured by means of a proton magnetometer around 1990.0 by the former Geophysical Enterprise of Tirana and covers all Albanian territory with an array of 28 sites (Duka and Bushati, 1991). In September 1994(epoch 1994, in the framework of a joint project between the CGG, PDTU and the former ING a new vector magnetic survey measuring F, inclination I and declination D (Chiappini et al, 1997(Chiappini et al, , 1999 covered the Albanian territory. The measurements were taken by using a Geometrics proton magnetometer and a Bartington fluxgate theodolite, together with a gyro-theodolite for the absolute determination of the geographical azimuth.…”

Section: Datamentioning

confidence: 99%

Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

et al. 2010

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Here we present a revised geomagnetic reference model for the region comprising Albanian territory, southeast part of Italian Peninsula and Ionian Sea from 1990 to 2010 with prediction to 2012. This study is based on the datasets of magnetic measurements taken during different campaigns in Albania and Italy in the time of concern, together with a total intensity data set from the Ørsted and CHAMP satellite missions. The model is designed to represent the Cartesian components, X , Y , Z and the total intensity F of the main geomagnetic field (and its secular variation SV) for the period of interest. To develop the model, we applied a Spherical Cap Harmonic Analysis (SCHA) of the geomagnetic potential over a 16 • cap with most of the observations concentrated in the central 4 • half-angle. The use of a larger cap than that containing the data was made to reduce the typical problems in SV modelling over small regions. Also a new technique, called "Radially Simplified Spherical Cap Harmonic Analysis" (RS-SCHA), was developed to improve the model especially in the radial variation of the geomagnetic field components. Both these models provide an optimal representation of the geomagnetic field in the considered region compared with the International Geomagnetic Reference Field model (IGRF-11) and can be used as reference models to reduce magnetic surveys undertaken in the area during the time of validity of the model, or to extrapolate the field till 2012.

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Section: Datamentioning

confidence: 99%

Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

et al. 2010

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“…Moreover, the radial variation of the magnetic field is implicitly described in the model, without need to assume a dipolar continuation of the field like as with polynomial models. Although a similar approach was used by Chiappini et al (1999), the field was analysed for a fixed epoch only, without secular variation modelling.…”

Section: Modelmentioning

confidence: 99%

A geomagnetic reference model for Albania, Southern Italy and the Ionian Sea from 1990 to 2005

Duka¹,

Gaya–Piqué²,

Santis³

et al. 2009

Annals of Geophysics

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Taking advantage of the measurements undertaken during the Albanian and Italian magnetic repeat station networks since 1990, as well as of a selected set of Ørsted satellite total field measurements, a magnetic reference model for the region comprising the Albanian territory, the southern part of the Italian Peninsula, and the Ionian Sea is presented. The model, designed to model the components of the main geomagnetic field for epochs between 1990 and 2005, has been developed by means of spherical cap harmonic analysis applied to a cap of semiangle 8°, larger than that investigated to take into account the appropriate spatial wavelength content of the main geomagnetic field over the region. The goodness of the fit to the real data suggests that the model can be used as a reference model to reduce magnetic surveys developed in the area during the time of validity of the model.

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“…the differences between the measured and modeled field values, it is possible to determine short wavelength anomalies. (Meloni et al, 1994;De Santis et al, 1997;Chiappini et al, 1999).…”

Section: Introductionmentioning

confidence: 96%

“…The lithospheric field varies with a shorter spatial scale compared to the more regular spatial trend of the core field, and is consequently mainly masked by it. The normal field residuals reveal the small scale field variations produced by the near-surface magnetic rocks (Newitt et al, 1996;Chiappini et al, 1999;Thébault et. al., 2006).…”

Section: Introductionmentioning

confidence: 99%

Estimation of the normal geomagnetic field and geological interpretation of the normal field anomalies over middle-northern Croatia

et al. 2011

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Based on the ground survey of total-field magnetic data at 53 sites, which recorded a time-series over the interval 20032005, the core field + long wavelength lithospheric field over the middle-northern Croatia region was calculated. The area of the survey was 18900 km 2 , an average distance between the neighbouring sites being 12 km. The results were reduced to 2004.5 epoch. This "normal" total-field was estimated using the firstorder Taylor polynomial as a function of geographic coordinates, and the polynomial coefficients were calculated with three methods of adjustment: simple and weighted least squares fits and adjustment according to the most frequent value. The stability of the normal field was tested using the Monte Carlo-type test, by decreasing the input data set in each adjustment (up to 90%). All obtained field residuals (measured-"normal") were mutually compared, as well as fit coefficients of the Taylor polynomials. The residual values indicate the presence of shorter-wavelength anomalies, specifically three major residual anomalies were found (106 nT, 74 nT and 57 nT). The geostatistical analysis of the ground survey data and the normal field residuals (respectively), using the median absolute deviation method, was further conducted in order to evaluate the calculated anomalies. The geological situation around the anomalies derived by the median absolute deviation method, and around the normal field residual anomalies, is given. The correlation was found between higher value anomalies of the normal field residuals, and shallow volcanic rocks and oil field, respectively.

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A normal reference field for the Ionian sea area

Cited by 5 publications

References 7 publications

Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

A geomagnetic reference model for Albania, Southern Italy and the Ionian Sea from 1990 to 2005

Estimation of the normal geomagnetic field and geological interpretation of the normal field anomalies over middle-northern Croatia

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