Geomagnetism
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This product contains a model of non-polar daily geomagnetic variation caused by ionospheric currents, including their variability with season and solar flux, derived in Dedicated Ionospheric Field Inversion chain. Spherical harmonic representation of the daily geomagnetic variations at mid and low latitudes (Sq and EEJ) and its induced counterpart.
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Series of core field models provided in terms of Gauss coefficients + covariance matrices + standard deviations of Gauss coefficients. Related to SW_CFW_SHA_2Y • Core field Gauss coefficients stored in the .shc file • The standard deviations of Gauss coefficients are stored in the .std file • The covariance matrices are stored in the .cov file The product consists in three files MCO_SHA_2Y shc and std file The format used has been set in accordance with the usual SHC format defined for this type of files. Units of Gauss coefficients are nT With a very similar format the standard deviations of the Gauss coefficients are provided in an independent file with the extension *.std The only difference in the format is on the first line where the B-spline order, and the number of intervals between spline knots, are not indicated. Units of standard deviations are nT. MCO_SHA_2Ycov file In this independent file with the extension *.cov, the covariance matrice upper triangles (i.e. variances and covariances) is provided. A covariance matrice being symmetric no information is lost. The format of the file is: • On the first line the series of dates (in decimal years) of the mean snapshot core field models associated with the covariance matrices. • On the next lines are indicated: the row index of the covariance matrix, the column index of the covariance matrix, followed by the time series of variances or covariances in the order given by the first line dates. Units of matrix elements are nT2.
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This product contains a series of core surface flow models coestimated with the core magnetic field and provided in terms of Toroidal and Poloidal spherical harmonic coefficients + covariance matrices + standard deviations of Gauss coefficients related to SW_MCO_SHA_2Y. The product consists in three files CFW_SHA_2Y txt file The file format is such that any line starting with a ”#” is a comment line. Then on the first (not- commented) line are given the minimum and maximum SH degree used, followed by the number of flow model snapshots. The second (not-commented) line contains the series of dates (in decimal years) corresponding to the flow snapshot models. On the remaining lines are given successively: a character ”T” or ”P” as an indication if the line is associated with a toroidal or poloidal flow coefficient, the SH degree of the coefficient, its order, and the time series for this coefficient at the dates indicated on the second line. CFW_SHA_2Y std file The file format is the same as for the txt file but are given the flow coefficient standard deviations in place of the coefficients CFW_SHA_2Y cov file In this independent file with the extension *.cov, the covariance matrice upper triangle (i.e. variances and covariances) is provided. A covariance matrice being symmetric no information is lost. The format of the file is: • On the first line the series of dates (in decimal years) of the mean snapshot core flow models associated with the covariance matrices. • On the next lines are indicated: the row index of the covariance matrix, the column index of the covariance matrix, followed by the time series of variances or covariances in the order given by the first line dates. Units of matrix elements are (km/y)2.
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Final map of the lithospheric field from the Revised Spherical Cap Harmonic analysis (R-SCHA) Dedicated Lithospheric Inversion, expressed in terms of high degree Spherical Harmonics
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The GRACE level-2 products are the main outputs from the GRACE and GRACE-FO missions. They consist of the time average (10-day, monthly) solutions of the Earth gravity field in spherical harmonics. GRACE is a joint project between the National Aeronautics and Space Administration ( NASA ) and the Deutsches Zentrum für Luft- und Raumfahrt ( DLR ). The mission has been proposed in 1996 jointly by the University of Texas at Austin, Center for Space Research ( UTCSR ), the German Research Centre for Geosciences ( GFZ ) and the Jet Propulsion Laboratories (JPL) in Pasadena. GRACE was selected in 1997 as second mission in NASA's Earth System Science Pathfinder ( ESSP ) program. As an innovation, the Principal Investigator Prof. Byron Tapley (UTCSR) and his team are ultimately responsible for developing the flight mission hardware from selection to a launch-ready condition, for accomplishing the scientific objectives and delivering the proposed measurements to the broader Earth science community and general public as expediently as possible. Co-Principal Investigator of the mission is Dr. Frank Flechtner (GFZ). Project management and systems engineering activities are carried out by JPL. GRACE-FO is a joint project between the National Aeronautics and Space Administration ( NASA ) and the GeoForschungsZentrum ( GFZ ) Potsdam. GRACE-FO, launched May 22, 2018, is a successor to the original GRACE mission. The Principal Investigator at NASA JPL is Felix landerer. Co-Principal Investigator of the mission is Dr. Frank Flechtner (GFZ). Project management and systems engineering activities are carried out by JPL.