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Magnetic field measurements from the satellite Kosmos-49, measured with proton magnetometer 1

Magnetic field measurements from the satellite Kosmos-49, measured with proton magnetometer 2

Composite OSG Logging Data from the PTA-2 borehole, Big Island, Hawai'i

Compilation of downhole logging data from the borehole PTA2 inside Bradshaw Army Camp in the saddle region between Mauna Kea and Mauna Loa on the Big Island of Hawai'i (Composite OSG Logging Data Hawaii PTA2.asc, ASCII). The PTA2 borehole was fully cored into a lava dominated rock sequence; open hole bit size was HQ. The data were derived from the following logging runs in February and June 2016: GR total natural Gamma ray, SGR spectrum natural Gamma ray, MS magnetic susceptibility, BS borehole sonic, DIP dipmeter, and ABI43 acoustic borehole imager. All sondes were run in an open hole section below the casing shoe: 885 - 1566 m except for the SGR, which was also measured in the cased upper section and the ABI43, which also logged a 40 m long section inside the casing.The logging data are complemented by Acoustic borehole image data that were measured in June 2016 in the open hole section below the casing shoe: 889 - 1566 m; open hole bit size was HQ. Logging sonde: ABI43 (ALT). The images are oriented to north (magnetic orientation). File formats are DLIS and WCL (WellCAD 5.2). The data are further described in Jerram et al. (2019, https://doi.org/10.5194/sd-25-15-2019).The logging data was measured and processed by the Operational Support Group (OSG) of ICDP hosted by GFZ Potsdam (see https://www.icdp-online.org/support/service/downhole-logging/?type=12&tx_icdpdatatables_pi1%5Bajaxcall%5D=1 for further information). Detailed information about the OSG Slimhole Wireline Logging Sondes ist provided at https://www.icdp-online.org/fileadmin/icdp/services/img/Logging/OSG_Slimhole_Sondes_Specs_pics_2019-05.pdf. The data are also described in Jerram et al. (2019), Millet et al. (2017, 2018) and Willoughby, L. (2015). The file structure is described in the header of the data file.

Monthly complex amplitudes of global M2 ocean tide induced electromagnetic field signals from 1990 to 2016

An electric current is induced by the motion of electrical conducting seawater through the ambient geomagnetic field. The periodic oceanic tidal flow induces an electric current that emits periodical time-variable electromagnetic field signals. The radial component of the ocean tide induced magnetic field signals has successfully been extracted from magnetic field observations of the satellite missions CHAMP and Swarm. It is known that the amplitudes of these electromagnetic signals are modulated by, among other influences, variations of the electrical seawater conductivity distribution of the ocean. The electrical seawater conductivity in return depends on seawater temperature and salinity. In order to analyse the influence of variations in oceanic temperature and salinity, we modelled a complete set of monthly time slices of three dimensional global complex amplitudes of these electromagnetic field signals for the years 1990 to 2016. In order to analyse solely the influence of variations in the climate sensitive seawater temperature and salinity on the ocean tide induced magnetic field signals, the influences of the secular variation of the geomagnetic field and temporal variations in ocean tide transports have been neglected.The data set is a supplement to the article of Petereit et al. (2019). The detailed method used to create this data set can be found in the data and methods section of the article and the associated data description file.Several datasets and models have been combined in order to compute the necessary models for the electrical conductivity of the Earth's surface and the ocean tide induced electric currents. These are the two main components needed for the modelling of the electromagnetic field signals that are emitted by the ocean tide induced electric currents.The model for the electrical conductivity of the Earth is composed of three components: a 1-D mantle conductivity distribution (Grayver et al., 2017), the time constant sediment conductivity (Laske & Masters, 1997) and the time-varying ocean conductivity. Ocean conductivity values were derived from a dataset of monthly global seawater temperature and salinity distributions that were derived from in-situ observations (Cabanes et al., 2013) using the TEOS-10 Toolbox (IOC, SCOR & APSO, 2010) to solve the Gibbs-seawater equation.The ocean-tide induced electric current density was computed as the vector product of the oceanic seawater conductivity, the tidal transports of the TPXO8-atlas (Egbert & Erofeeva, 2002) and ambient geomagnetic field of the IGRF-12 (Thébault et al., 2015). While, the oceanic seawater conductivity was variable in time, the tidal transports and the field strength of the ambient geomagnetic field have been kept constant.

Alternate_Mag_Absolutes - A software package for Magnetic Absolute Measurements with arbitrarily distributed DI Theodolite Orientations

This data publication includes a matlab software package as described in Brunke (2017). In addition to the Matlab software, we provide three test dataset from the Niemegk magnetic observatories (NGK). We present a numerical method, allowing for the evaluation of an arbitrary number (minimum 5 as there are 5 independent parameters) of telescope orientations. The traditional measuring schema uses a fixed number of eight orientations (Jankowski et al, 1996). Our method provides D, I and Z base values and calculated uncertitudes of them. A general approach has significant advantages. Additional measurements may by seamlessly incorporate for higher accuracy. Individual erroneous readings are identified and can be discarded without invalidating the entire data set, a-priory information can be incorporated. We expect the general method to ease requirements also for automated DI-flux measurements. The method can reveal certain properties of the DI-theodolite, which are not captured by the conventional method. Based on the alternative evaluation method, a new faster and less error prone measuring schema is presented. It avoids the need to calculate the magnetic meridian prior to the inclination measurements. Measurements in the vicinity of the magnetic equator become possible with theodolites without zenith ocular.

CH-ME-3-MAG - CHAMP 1 Hz Combined Magnetic Field Time Series (Level 3)

This is a Level 3 data daily file product from various scientific and utility sensors on board of the `LEO' satellite 'CHAMP' with magnetic field data given by a time resolution of 1 Hz. Thise Level 3 data type is build to hold and merge finally corrected data, focusing on mature data calibration and corrections -- as well as internal consistency. This Level 3 data product is intended to supersede the various Level 2 versions with calibrated magnetic field readings from the CHAMP mission distributed hitherto and should be fitted for scientific use, assembling time series of scalar magnetic field values (but not directly readings from the scalar Overhauser sensor), vector magnetic field data from the boom-mounted Fluxgate 'FGM' sensors and attitude data from the ('ASC') boom-mounted Star Cameras. The vector data are given both in the satellite-bound sensor ('FGM') system and the Earth Centered Earth Fixed local 'NEC' (North-East-Center) system. The attitude time series, processed and cleaned, are represented by quaternions describing the satellite attitude related to the celestial system. The readings of the scalar OVM (Overhauser) absolute magnetometer at the top of the boom are not supplied directly, but were used during calibration of the vector magnetometer readings. The files with daily time coverage are in the (binary and self-describing) 'CDF' file format and accompanied, beside the generic 'CDF'-format timestamp, by the satellite's geocentric positions and utility information like quality flags. The full product and format descriptions are provided in the associated Scientific Technical Report - Data (GFZ Section 2.3, 2019. https://doi.org/10.2312/GFZ.b103-19104). ---------- 13 March 2025: addition of Jan Rauberg as co-author

CH-ME-2-FGM-SCI - CHAMP 50 Hz Magnetic Field Vector Time Series in Sensor- and ECEF-(NEC)-System (Level 2)

Earth's magnetic field vector time series from `LEO' satellite 'CHAMP' for the 'CHAMP' mission period in high, unaveraged 50 Hz time resolution, using measurements from the FGM vector magnetometers and `ASC' Star Sensors on the mid-boom optical bench. The vector data are corrected and calibrated (by using the Overhauser scalar magnetometer as reference). The magnetic field vector data are given both in the satellite-bound sensor (`FGM') system and in the Earth Centered Earth Fixed local `NEC' (North-East-Center) system. For the latter the attitude time series (`ASC'), processed and cleaned, represented by quaternions describing the satellite attitude related to the celestial system, were used for the transformation. The files with daily time coverage are in the (binary and self-describing) `CDF' file format and accompanied, beside the `CDF'-format generic timestamp, by the satellite's geocentric positions and utility information like quality flags.The full product and format descriptions are provided in the associated Scientific Technical Report - Data (GFZ Section 2.3, 2019. http://doi.org/10.2312/GFZ.b103-19104).

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