Against the backdrop of global change, both in terms of climate and demography, there is an increasing need for monitoring global water cycle. The publicly available global database is very limited in its spatial and temporal coverage worldwide. Moreover, the acquisition of in situ data and their delivery to the database are on the decline since the late 1970s be it for economical, political or other reasons.
Given the insufficient monitoring from in situ gauge networks, and without any outlook of improvement, spaceborne approaches are currently being investigated. Satellite-based Earth observation with its global coverage and homogeneous accuracy has been demonstrated to be a potential alternative to in situ measurements. The Institute of Geodesy (GIS), within the Faculty of Aerospace Engineering and Geodesy at University of Stuttgart has a long-standing expertise, both theoretically and practically, in dynamic satellite geodesy. In recent years, GIS initiated and participated in studies and projects on application of spaceborne geodetic sensors for hydrological studies. HydroSat provides the results of these studies and projects, in which spaceborne geodetic sensors are used to estimate Surface water extent from satellite imagery Water level from satellite altimetry Water Storage Anomaly from satellite gravimetry River discharge from satellite altimetry, imagery or gravimetry
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, Zitat), which are mostly available within 15 to 60 minutes delay, followed by Rapid Science Orbit (RSO, Zitat) products with a latency of two days and finally the Precise Science Orbit (PSO) which, with a latency of up to a few weeks or longer in the case of reprocessing campaigns, are the most delayed. The absolute positional accuracy increases from NRT to PSO.
This dataset compiles the PSO products for various LEO missions and GNSS constellation in sp3 format.
GNSS Constellation:
- GPS
LEO Satellites:
- ENVISAT
- Jason-1
- Jason-2
- Jason-3
- Sentinel-3A
- Sentinel-3B
- Sentinel-6A
- TOPEX
Each solution follows specific requirements and parametrizations which are named in the respective processing metric table.
The data set provides GFZ VER13 orbits of altimetry satellites:ERS-1 (August 1, 1991 - July 5, 1996),ERS-2 (May 13, 1995 - February 27, 2006),Envisat (April 12, 2002 - April 8, 2012),TOPEX/Poseidon (September 23, 1992 - October 8, 2005),Jason-1 (January 13, 2002 - July 5, 2013) andJason-2 (July 5, 2008 - April 5, 2015)derived at the time spans given at the GFZ German Research Centre for Geosciences (Potsdam, Germany) within the Sea Level phase 2 project of the European Space Agency (ESA) Climate Change Initiative using "Earth Parameter and Orbit System - Orbit Computation (EPOS-OC)" software (Zhu et al., 2004) and the Altimeter Database and processing System (ADS, http://adsc.gfz-potsdam.de/ads/) developed at GFZ. The orbits were computed in the ITRF2014 terrestrial reference frame for all satellites using common, most precise models and standards available and described below.The ERS-1 orbit is computed using satellite laser ranging (SLR) and altimeter crossover data, while the ERS-2 orbit is derived using additionally Precise Range And Range-rate Equipment (PRARE) measurements. The Envisat, TOPEX/Poseidon, Jason-1, and Jason-2 orbits are based on Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) and SLR observations. For Envisat, altimeter crossover data were used additionally at 44 of 764 orbital arcs with gaps in SLR and DORIS data.The orbit files are available in the Extended Standard Product 3 Orbit Format (SP3-c). Files are gzip-compressed. File names are given as sate_YYYYMMDD_SP3C.gz, where "sate" is the abbreviation (ENVI, ERS1, ERS2, JAS1, JAS2, TOPX) of the satellite name, YYYY stands for 4-digit year, MM for month and DD for day of the beginning of the file. More details on these orbits are provided in Rudenko et al. (2018) to which these orbits are supplementary material.