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[en] Complete text of publication follows. Geomagnetic field observations over Romanian territory have started with irregular measurements in the late XIXth century. In 1943, the foundation of Surlari National Geomagnetic Observatory marks the beginning of a new era in the systematic study of geomagnetic field by a continuous recording of its variations and by carrying out standard absolute measurements. Since 1998, Surlari observatory is an IMO (INTERMAGNET observatory). Over the next years, the basic equipment of the observatory has been affected by significant physical and moral wear, especially under the context of rapidly developing technologies and of the high performance acquisition process, so that the observatory was faced a growing risk not to continue to be part of the INTERMAGNET observatory network. Since March 2009, in the frame of a bi-lateral cooperation, the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences supports the Geological Institute of Romania to upgrade its traditional and reliable observatory for the up-to-date INTERMAGNET standard. The general objective of the project consists in increasing competitiveness in order to maintain partnerships, as well as to add innovative products and services capable of meeting present and future requirements.
[en] Poleward propagating on-off switching aurorae and equatorward propagating aurorae, otherwise similar, were observed simultaneously at Rabbit Lake and La Ronge, respectively, for about 40 min before dawn of Feb 20, 1980. Rabbit Lake is a high auroral latitude site at the northern end of the Saskatchewan chain of stations for the Pulsating Aurora Campaign, whereas La Ronge, due south of Rabbit, is almost at the southern edge of the auroral zone. The repetition periods of the on-off switching aurorae are about 6 to 13 s. The poleward propagating aurorae had well defined fronts of light which extended a few hundred kilometres or more in the east-west direction. The light fronts of the equatorward propagating aurorae, though comparable in extent, were less well defined: they were thicker and fuzzier. The poleward propagating aurorae moved with a speed of approximately 10 km/s whereas the equatorward ones did so with a slightly greater velocity. Geomagnetic field fluctuations were concurrent with the aurorae at both sites. At Rabbit Lake, northward (southward) field changes were associated with upward (downward) changes, whereas the trend is reversed at La Ronge, viz., northward (southward) changes with downward (upward) changes. These trends are consistent with a model of a periodic occurrence of two line currents, westward and eastward, the former moving poleward north of Rabbit Lake and the latter approaching La Ronge from the north
[en] Complete text of publication follows. After the installation of geomagnetic observatory 'Abdus Salaam' in Sonmiani (South-west of Pakistan), Pakistan has established another geomagnetic observatory at Islamabad (33.75degN, 72.87degE), located in the North-east mountainous region of the country. Since Pakistan is spread along 23-40degN, 60-80degE, the newly established observatory will provide enhanced coverage of geomagnetic activity in the country. During 2008, repeat station work at three selected sites (Multan, Gilgit and Skardu) was also carried out to compare with the survey work previously done during 2005. All this activity was the result of collaboration between SUPARCO and IRM started in 2006 and which culminated in July 2008 by this joint installation and measurement campaign. Experiences during establishment of the observatory and repeat station comparisons/results are described in this study.
[en] The Auroral Electrojet index (AE) is discussed and a brief description is given of the derivation of 11-station 2.5-min AE indices for 1974. Tables are given of hourly average indices for each day of the year, the stations making the main contribution to the hourly indices, and of the average monthly quiet-time level of horizontal fields (H) at each magnetic observatory. Graphs of the index variations are included for each day of 1974
[en] Statistical dependences are presented between the magnetic activity main indices Kp, AE, Al and Q. The connection between the indices is given in the equal from of a third-degree polynomial and also in the form of a linear dependence
[en] Complete text of publication follows. High precision measurements of the geomagnetic field have been and are essential to provide insight into the internal structure of the Earth and the solar interaction with the Earth's magnetic field. These measurements reveal the resulting magnetic field that stems from the superposition of three sources: the core field, the crustal field and the current driven field. The spatial and temporal structure of these sources are very different from each other, and therefore not only signal extraction methods and modelling but also measurement strategies have to be taken into account in order to successfully separate these signal contributors. Furthermore, this decomposition process requires that the global field is known at any given time with a relatively high accuracy, wherefore accurate magnetic field mapping is only viable using spaceborne observations. The data obtained from one single spacecraft is extremely valuable. The first mission to ever map the Earth's magnetic field vector at LEO was the NASA MAGSAT (1978-9). Twenty years later, the Danish Orsted micro satellite (1999-), the German CHAMP (2000-), the Argentine SAC-C (2000-5) have been designed specifically for mapping the LEO magnetic field. Common to these resent missions is the magnetometry package, which utilizes a vector field magnetometer co-mounted with a star tracker (2 in the case of CHAMP) on an optical bench. As the accuracy of the instrument package has constantly increased, as well as the modelling methods have been improved towards optimized signal decomposition, it has been realized that simultaneous data from several points in space is needed, if the ultimate modelling barrier, the spatial-temporal ambiguity, has to be broken. The ESA Swarm mission under the Living Planet Programme consists of three identical spacecraft orbiting in near polar orbits with altitudes varying between 400km to 550km. This constellation is to map the magnetic field of the Earth with unprecedented spatial and temporal accuracy. For this purpose, each spacecraft will be equipped with a vector field magnetometer and three star trackers co-mounted in an optical bench, which will ensure 100% data coverage over the orbit with arcsecond accuracy. This accuracy of the magnetometry package is essential for fulfilling the mission objectives. This paper describes the basic design characteristics and the performance potentials of the Swarm Magnetometry Package. The key performance parameter is an absolute attitude recovery accuracy in the arcsecond range over time, temperature and aging. The methods used to achieve and validate this accuracy are discussed, as well as the potential for using this methodology on other future missions with extreme stability and accuracy demands.