scholarly journals The 1990.0 magnetic repeat station survey and normal reference fields for Italy

1994 ◽  
Vol 37 (5) ◽  
Author(s):  
A. Meloni ◽  
O. Battelli ◽  
A. De Santis ◽  
G. Dominici
Keyword(s):  
Secular Variation ◽  
Data Reduction ◽  
Measuring Equipment ◽  
Field Data ◽  
Data Mapping ◽  
Reduction Procedure ◽  
Normal Field ◽  
Repeat Station ◽  
Magnetic Network ◽  
Reference Fields

A survey of 116 repeat stations of the Italian Magnetic Network was carried out between 1989 and 1992. We describe the characteristics of the selected network repeat station sites, the characteristics of the measuring equipment, the data reduction procedure and the analysis in terms of normal field, data mapping and secular variation. Together with the values from our previous campaigns, we also determined, for all elements, the normal fields of secular variation. The new repeat station data are listed. Results, maps and normal fields are discussed with respect to previous work and future survey plans.

scholarly journals Italian Magnetic Network and magnetic reference fields at 2010.0

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Guido Dominici ◽  
Antonio Meloni ◽  
Angelo Di Ponzio ◽  
Massimo Miconi
Keyword(s):  
Magnetic Field ◽  
Magnetic Measurements ◽  
Second Order ◽  
Reduction Procedure ◽  
Average Spacing ◽  
First Order ◽  
Order Polynomial ◽  
Magnetic Network ◽  
Selection Of ◽  
Reference Fields

<p>The Istituto Nazionale di Geofisica e Vulcanologia (INGV) has systematically undertaken the task of making measurements of the Earth's magnetic field in Italy. By tradition and because of the elongated geometric shape of our peninsula and islands, in Italy, a grid of more than 110 points, called the first order repeat stations, with an average spacing around 55-60 km, is in operation. Over this grid the measurements are repeated regularly, every 5 years. A survey of 131 repeat stations of the Italian Magnetic Network (including 2 observatories, 11 stations in Albania, 3 stations in Corsica and 1 in Malta) was carried out between 2009 and 2010 with the main purpose of updating our magnetic cartography. We describe the characteristics of magnetic first and second order networks, the magnetic measurements and the data reduction procedure. In agreement with the recommendations of MagNetE Committee, we report new repeat station data measured and reduced at 2010.0. An analytical expression, a second order polynomial, in latitude and longitude for the field elements, was determined, and coefficients for 2010.0 and average secular variation over the period 2005-2010, were obtained. The new maps for Italy, for D, F, H and Z at the epoch 2010.0, are shown. A selection of stations from the Italian Magnetic Network, based on their low values of anomaly with respect to a 'normal' field, is also proposed for future surveys.</p>

scholarly journals Repeat station data compared to a global geomagnetic field model

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Monika Korte ◽  
Vincent Lesur
Keyword(s):  
Magnetic Field ◽  
Secular Variation ◽  
Global Model ◽  
Time Interval ◽  
Night Time ◽  
Core Field ◽  
Repeat Station ◽  
Station Data ◽  
Long Term Trends

<p>Geomagnetic repeat station surveys with local variometers for improved data reductions have been carried out in Germany for about ten years. For nearly the same time interval the satellites Ørsted and CHAMP have provided a good magnetic field data coverage of the whole globe. Recent global field models based on these satellite data together with geomagnetic observatory data provide an improved description of the core field and secular variation. We use the latest version of the GFZ Reference Internal Magnetic Model to compare the magnetic field evolution predicted by that model between 2001 and 2010 to the independent repeat station data collected over the same time interval in Germany. Estimates of crustal bias at the repeat station locations are obtained as averages of the residuals, and the scatter or trend around each average provides information about influences in the data from field sources not (fully) described by the global model. We find that external magnetic field signal in the order of several nT, including long-term trends, remains both in processed annual mean and quiet night time repeat station data. We conclude that the geomagnetic core field secular variation in this area is described to high accuracy (better than 1 nT/yr) by the global model. Weak long-term trends in the residuals between repeat station data and the model might indicate induced lithospheric anomalies, but more data are necessary for a robust analysis of such signals characterized by very unfavorable signal-to-noise ratio.</p>

scholarly journals Unified radio interferometric calibration and imaging with joint uncertainty quantification

2019 ◽  
Vol 627 ◽  
pp. A134 ◽  
Author(s):  
Philipp Arras ◽  
Philipp Frank ◽  
Reimar Leike ◽  
Rüdiger Westermann ◽  
Torsten A. Enßlin
Keyword(s):  
Field Theory ◽  
Data Reduction ◽  
Bayesian Method ◽  
Brightness Distribution ◽  
Variational Inference ◽  
Reduction Procedure ◽  
Actual Observation ◽  
Sky Brightness ◽  
Cross Calibration ◽  
Future Work

The data reduction procedure for radio interferometers can be viewed as a combined calibration and imaging problem. We present an algorithm that unifies cross-calibration, self-calibration, and imaging. Because it is a Bayesian method, this algorithm not only calculates an estimate of the sky brightness distribution, but also provides an estimate of the joint uncertainty which entails both the uncertainty of the calibration and that of the actual observation. The algorithm is formulated in the language of information field theory and uses Metric Gaussian Variational Inference (MGVI) as the underlying statistical method. So far only direction-independent antenna-based calibration is considered. This restriction may be released in future work. An implementation of the algorithm is contributed as well.

Application of the Transient Test Technique to Measure Local Heat Transfer Coefficients Associated With Augmented Airfoil Cooling Passages

1987 ◽  
Author(s):  
H. J. Saabas ◽  
S. C. Arora ◽  
W. Abdel Messeh
Keyword(s):  
Heat Transfer ◽  
Data Reduction ◽  
Order Approximation ◽  
Bulk Temperature ◽  
Image Analysis System ◽  
Reduction Procedure ◽  
Test Technique ◽  
True Value ◽  
Time Space ◽  
Made In

The failure of a turbine airfoil is a local phenomena. However, to date, the design of these airfoils has been based on steady state heat transfer tests that are capable of yielding only locally averaged data. To overcome this limitation, a transient technique using active surface coatings has been developed and is capable of yielding local data. This technique has been used to determine the Nusselt number distributions within augmented passages typical of gas turbine airfoils. However, certain assumptions have been made in these analyses without verification. This paper will address this aspect of the problem, as well as an improved data reduction procedure, and an alternative error analysis. The data reduction procedure has been improved by incorporating a higher order approximation to the convective boundary condition, and by introducing a means of calculating the fluid bulk temperature-time-space profile. An image analysis system which yields an unbiased means of determining the time required for the surface to reach a specified temperature is introduced. Furthermore, it was observed that for augmented surfaces, the one dimensional conduction assumption made in the heat transfer solution is not valid for all times. Finally, treating the experimentally obtained quantities as values that are randomly distributed about some true value is not correct for all experimentally measured quantities.

Analysis and interpretation of VHF-radar data

1994 ◽  
Vol 12 (8) ◽  
pp. 725-732 ◽  
Author(s):  
R. Rüster
Keyword(s):  
Data Reduction ◽  
Radar Data ◽  
Reduction Procedure ◽  
Vhf Radar ◽  
Contaminated Data ◽  
General Data

Abstract. Doppler measurements have been carried out during a variety of observational campaigns using the stationary and the mobile SOUSY-VHF-Radars. The general data reduction procedure is presented in some detail. Particular emphasis is placed upon possible problems arising from contaminated data and solutions are proposed. Some results from measurements at tropospheric and mesospheric heights are presented.

scholarly journals VERY LARGE ARRAY 1.4 GHz OBSERVATIONS OF THE GOODS-NORTH FIELD: DATA REDUCTION AND ANALYSIS

2010 ◽  
Vol 188 (1) ◽  
pp. 178-186 ◽  
Author(s):  
Glenn E. Morrison ◽  
Frazer N. Owen ◽  
Mark Dickinson ◽  
Rob J. Ivison ◽  
Edo Ibar
Keyword(s):  
Data Reduction ◽  
Field Data ◽  
Large Array ◽  
Very Large Array

Field In-Ice Pressure Sensor Response Tests

1983 ◽  
Vol 105 (1) ◽  
pp. 6-11
Author(s):  
A. C. T. Chen ◽  
J. S. Templeton
Keyword(s):  
Pressure Sensor ◽  
Data Reduction ◽  
Broad Class ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Ice Sheet ◽  
Sensor Response ◽  
Sensor Output ◽  
Reduction Procedure ◽  
Ice Pressure

An ice pressure sensor has been designed and built at Exxon Production Research Company (EPR) to measure the pressure in an ice sheet. Laboratory and analytical studies were performed to establish a data reduction procedure to relate the pressure sensor output to the pressure in the ice sheet. However, because of the complex mechanical behavior of sea ice, the present experiment was conducted to validate this data reduction procedure. The validated procedure is considered applicable to a broad class of embedded ice pressure sensors. Field in-ice pressure sensor response tests were conducted near Prudhoe Bay, Alaska, between February and April of 1978. Twenty-two tests were conducted on three test blocks of ice to investigate the in-ice response of three ice pressure sensors. An ice block measuring 10 ft by 20 ft and of full thickness of the natural annual ice was cut free from the surrounding ice sheet after the pressure sensor was installed at the center of the block. This ice block was loaded by an in-situ hydraulic ice loading device capable of delivering approximately two million lb of load. The pressure sensor output and the test load were monitored continuously during each test so that the pressure sensor output could be compared directly to the corresponding applied pressure. The test results indicated ratios of applied ice pressure to measured sensor pressure within the range hindcast by theoretical analysis.

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