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GDEMM2024: 30 Arcsec Global Digital Elevation Merged Model 2024, a suite for Earth relief

We merged various digital elevation models (DEMs) published in the recent years and created an up-to-date composite and global solution for Earth’s topography and bathymetry. Compared to the original geographically limited data sets, the final product is a seamless merged grid which additionally provides high resolution and accuracy topography and depth globally. We provide Earth relief grids w.r.t EIGEN-6C4 global geoid in terms of surface and bedrock elevation, ice thickness, and land-type masks which have been substantially improved w.r.t the global grids found in literature. We assessed the quality of the merged surface elevations w.r.t the heights given for about globally distributed 5000 ITRF stations. The merged surface model shows improvement of a factor of three w.r.t the other commonly used DEMs in terms of standard deviation. In addition to the four grids, GDEMM2024_SUR, GDEMM2024_BED, GDEMM2024_ICE, and GDEMM2024_LTM, we provide two additional files, the surface elevation without water (GDEMM2024_TBI) and the GDEMM2024_GEO file to transform the heights above EIGEN_6C4 geoid to ellipsoidal heights. The final grids are provided both in 30 arcsec and 1arcmin resolution and in GeoTIFF format which is one of the standards that is available in GMT (Generic Mapping Tools), GDAL (Geospatial Data Abstraction Library) and in almost all GIS software systems.

GFZ TerraSAR-X Near Realtime Orbits (version 2)

This dataset provides Near Realtime Orbits (NRT) from the Low Earth Orbiter (LEO) satellite TerraSAR-X. It is part of the compilation of GFZ NRT products for various LEO missions and the appropriate GNSS constellation in sp3 format. The individual solutions for each satellite mission are published with individual DOI as part of the compilation (Schreiner et al., 2022). The TerraSAR-X NRT cover the period - from 2007 264 to up-to-date The LEO NRTs in version 2 are generated based on the 30-hour GPS NRTs in two pieces for the actual day with arc lengths of 14 hours and overlaps of 2 hours. One starting at 22:00 and ending at 12:00, one starting at 10:00 and ending at 24:00. Due to the extended length of the constellation, there is no need to concatenate several constellations for day-overlapping arcs. The accuracy of the LEO NRTs is at the level of 1-2 cm in terms of SLR validation. Each solution in version 2 is given in the Conventional Terrestrial Reference System (CTS) based on the IERS 2010 conventions and related to the ITRF-2014 reference frame. The exact time covered by an arc is defined in the header of the files and indicated as well as in the filename.

GFZ TanDEM-X Rapid Science Orbits (version 1)

This dataset provides Rapid Science Orbits (RSO) from the Low Earth Orbiter (LEO) satellite TanDEM-X. It is part of the compilation of GFZ RSO products for various LEO missions and the appropriate GNSS constellation in sp3 format. The individual solutions for each satellite mission are published with individual DOI as part of the compilation (Schreiner et al., 2022). • The TanDEM-X RSO cover the period: o from 2010 173 to up-to-date The LEO RSOs in version 1 are generated based on the 24-hour GPS RSOs in two pieces for the actual day with arc lengths of 14 hours and overlaps of 2 hours. One starting at 22:00 and ending at 12:00, one starting at 10:00 and ending at 24:00. For day overlapping arcs two 24h GNSS constellations are concatenated. The accuracy of the LEO RSOs is at the level of 1-2 cm in terms of SLR validation. Each solution in version 1 is given in the Conventional Terrestrial Reference System (CTS) based on the IERS 2003 conventions and related to the ITRF-2008 reference frame. The exact time covered by an arc is defined in the header of the files and indicated as well as in the filename.

GFZ TerraSAR-X Rapid Science Orbits (version 1)

This dataset provides Rapid Science Orbits (RSO) from the Low Earth Orbiter (LEO) satellite TerraSAR-X. It is part of the compilation of GFZ RSO products for various LEO missions and the appropriate GNSS constellation in sp3 format. The individual solutions for each satellite mission are published with individual DOI as part of the compilation (Schreiner et al., 2022). • The TerraSAR-X RSO cover the period - from 2007 264 to up-to-date The LEO RSOs in version 1 are generated based on the 24-hour GPS RSOs in two pieces for the actual day with arc lengths of 14 hours and overlaps of 2 hours. One starting at 22:00 and ending at 12:00, one starting at 10:00 and ending at 24:00. For day overlapping arcs two 24h GNSS constellations are concatenated. The accuracy of the LEO RSOs is at the level of 1-2 cm in terms of SLR validation. Each solution in version 1 is given in the Conventional Terrestrial Reference System (CTS) based on the IERS 2003 conventions and related to the ITRF-2008 reference frame. The exact time covered by an arc is defined in the header of the files and indicated as well as in the filename.

GFZ TanDEM-X Rapid Science Orbits (version 2)

This dataset provides Rapid Science Orbits (RSO) from the Low Earth Orbiter (LEO) satellite TanDEM-X. It is part of the compilation of GFZ RSO products for various LEO missions and the appropriate GNSS constellation in sp3 format. The individual solutions for each satellite mission are published with individual DOI as part of the compilation (Schreiner et al., 2022). • The TanDEM-X RSO cover the period: from 2010 173 to up-to-date The LEO RSOs in version 2 are generated based on the 30-hour GPS RSOs in two pieces for the actual day with arc lengths of 14 hours and overlaps of 2 hours. One starting at 22:00 and ending at 12:00, one starting at 10:00 and ending at 24:00. Due to the extended length of the constellation, there is no need to concatenate several constellations for day-overlapping arcs. The accuracy of the LEO RSOs is at the level of 1-2 cm in terms of SLR validation. Each solution in version 2 is given in the Conventional Terrestrial Reference System (CTS) based on the IERS 2010 conventions and related to the ITRF-2014 reference frame. The exact time covered by an arc is defined in the header of the files and indicated as well as in the filename.

GFZ Rapid Science Orbits

Orbital products describe positions and velocities of satellites, be it the Global Navigation Satellite System (GNSS) satellites or Low Earth Orbiter (LEO) satellites. These orbital products can be divided into the fastest available ones, the Near Realtime Orbits (NRT), which are mostly available within 15 to 60 minutes delay, followed by Rapid Science Orbit (RSO) products with a latency of two days and finally the Precise Science Orbit (PSO) which, with a latency of up to a few weeks, are the most delayed. The absolute positional accuracy increases with the time delay. This dataset compiles the RSO products for various LEO missions and the appropriate GNSS constellation in sp3 format. The individual solutions for each satellite mission are published with individual DOI as part of this compilation. GNSS Constellation: • GNSS 24h (v01) • GNSS 30h (v02) LEO Satellites: • CHAMP • GRACE • GRACE-FO • SAC-C • TanDEM-X/ TerraSAR-X Each solution is given in the Conventional Terrestrial Reference System (CTS). • The GNSS RSOs are 30-hour long arcs starting at 21:00 the day before the actual day and ending at 03:00 the day after. The accuracy of the GPS RSO sizes at the 3-cm level in terms of RMS values of residuals after Helmert transformation onto IGS combined orbit solutions (Version 1 GNSS RSOs are 24-hour long arcs starting at 00:00 and ending at 24:00 the actual day). • The LEO RSOs are generated based on these 30-hour GNSS RSOs in two pieces for the actual day with arc lengths of 14 hours and overlaps of 2 hours. One starting at 22:00 and ending at 12:00, one starting at 10:00 and ending at 24:00. The accuracy of the LEO RSOs is at the level of 1-2 cm in terms of SLR validation. The exact time covered by an arc is defined in the header of the files and indicated as well as in the filename. This dataset compiles RSO products for various LEO missions and the corresponding GNSS constellation in sp3 format in a revised processing version 2. The switch from previous version 1 to 2 was performed on 18-Feb-2019. Major changes from version 1 to 2 are the change from IERS 2003 to IERS 2010 conventions and ITRF 2008 to ITRF-2014, as well as the temporal extension of the GNSS constellation from previous 24 hours (version 1) to 30 hours (version 2) arcs. This temporal expansion eliminates the chaining of two consecutive 24-hour GNSS constellation solutions previously used to process day-overlapping LEO arcs in Version 1. This 24h GNSS constellation (Version 1) will continue to operate and be stored on the ISDC ftp server, as discussed in more detail in Section 8.1. All RSO LEO arcs will no longer be continued in version 1 after the changeover date and will only be available in version 2 since then.

GFZ TerraSAR-X Rapid Science Orbits (version 2)

This dataset provides Rapid Science Orbits (RSO) from the Low Earth Orbiter (LEO) satellite TerraSAR-X. It is part of the compilation of GFZ RSO products for various LEO missions and the appropriate GNSS constellation in sp3 format. The individual solutions for each satellite mission are published with individual DOI as part of the compilation (Schreiner et al., 2022). • The TerraSAR-X RSO cover the period - from 2007 264 to up-to-date The LEO RSOs in version 2 are generated based on the 30-hour GPS RSOs in two pieces for the actual day with arc lengths of 14 hours and overlaps of 2 hours. One starting at 22:00 and ending at 12:00, one starting at 10:00 and ending at 24:00. Due to the extended length of the constellation, there is no need to concatenate several constellations for day-overlapping arcs. The accuracy of the LEO RSOs is at the level of 1-2 cm in terms of SLR validation. Each solution in version 2 is given in the Conventional Terrestrial Reference System (CTS) based on the IERS 2010 conventions and related to the ITRF-2014 reference frame. The exact time covered by an arc is defined in the header of the files and indicated as well as in the filename.

High resolution Digital Elevation Model of Merapi summit in 2015 generated by UAVs and TLS and TanDEM-X

This data is an high resolution Digital Elevation Model (DEM) generated for the Merapi summit by combining terrestrial laser scanning (TLS) and unmanned aerial vehicles (UAVs) photogrammetry data and TanDEM-X data acquired in the years between 2012 and 2017. The structures of the data are further analysed in Darmawan et al. 2017a (http://doi.org/10.1016/j.jvolgeores.2017.11.006), and a previous DEM was available in Darmawan et al. 2017b (https://doi.org/10.5880/GFZ.2.1.2017.003). The 3D point clouds of the different data were merged and interpolated to a raster format (Geotiff format).

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