ABSTRACT: OSTM/JASON-2 is a follow-on mission continuing the TOPEX/Poseidon and Jason-1, and is designed to ensure continuity of high quality measurements for ocean science and to provide operational products for assimilation and forecasting applications. The Jason-2 satellite was launched on 20 June 2008 and reached its nominal repetitive orbit on 4 July 2008. The level-2 X-GDR are available as 3 ... datatypes: Operational Geophysical Data Records (OGDR), Interim Geophysical Data Records (IGDR) and final Geophysical Data Records (GDR). The OGDRs are near-real-time records and are generated every 3-5 hours. They are based on orbits from DORIS propagator and forecast meteorological fields for the geophysical corrections. The IGDRs are based on preliminary DORIS ephemeris, analyzed meteorological grids, and preliminary auxiliary data files. The IGDRs have a latency of 1 - 2 days. The S-IGDR is a superset of the IGDR, containing the original radar echo "waveform" data. The GDRs are based on final high-precision DORIS (perhaps combined with GPS) ephemeris, final meteorological grids, ancillary and auxiliary data files. The S-GDR is a superset of the GDR, containing the waveform data. The S-GDRs are generated every 10 days. Sea Surface Height Anomaly (SSHA) files are available for IGDR and GDR. All files are available in NetCDF format and the OGDRs are also available in BUFR format. Jason-2 level-2 X-GDR data are distributed through the NOAA/NESDIS Comprehensive Large Array-data Stewardship System (CLASS:http://www.class.noaa.gov). These data are archived at the National Oceanographic Data Center (NODC) as NODC accession number 0043269 (http://www.nodc.noaa.gov/cgi-bin/search/prod/accessionsView.pl/deta...) and available via FTP at ftp://data.nodc.noaa.gov/pub/data.nodc/jason2, HTTP at http://data.nodc.noaa.gov/jason2 and OPeNDAP at http://data.nodc.noaa.gov/opendap/jason2.
SUPPLEMENTAL INFORMATION: Satellite altimetry data applications include validation and assimilation into global wave models, high seas hazards monitoring, sea surface height and ocean currents (hurricane intensity forecasts and assimilation into operational ocean models, multi-mission altimetry, fisheries, and marine transport.
CURRENTNESS REFERENCE: ground condition
SPATIAL DATA ORGANIZATION INFORMATION Indirect Spatial Reference: Jason-2's orbit is identical to that of Jason-1 (and that of Topex/Poseidon previously). It is optimized to study large-scale ocean variability and to provide coverage of 90% of the world's oceans over a ten-day cycle. Jason-2's high altitude (1,336 kilometres) reduces interactions with the Earth's atmosphere and gravity field to a minimum, thus making orbit determination easier and more precise. The orbit inclination of 66 degrees North and South enables the satellite to cover most of the globe's unfrozen oceans. The orbit's repeat cycle is just under 10 days (9.9156 days to be precise, i.e., 10 days minus two hours) - in other words, the satellite passes over the same point on the Earth's surface (to within one kilometre) every ten days. This cycle is a trade-off between spatial and temporal resolution designed for the study of large-scale ocean variability. The fact that the orbit is prograde and not sun-synchronous also avoids aliasing of different tidal components at the same frequency. The orbit is also designed to pass over two dedicated ground calibration sites: Cap Senetosa in Corsica and the Harvest oil rig platform in California, USA. Direct Spatial Reference: Point SDTS Point and Vector Object Type: Point
NATIVE: .All files are available in NetCDF format and the OGDRs (Operational Geophysical Data Records) are also available in BUFR ((Binary Universal Form of Representation of meteorological data) format.
Electronic download (FTP) of the data is free. There is a fee for copies of data on physical media. Optical disks are $25.00 per unit and magnetic tape is $100 per unit. Price does not include additional service and handling costs. All GDR data are free for public users.
PURPOSE: To ensure operational continuity for the collection and distribution of high-resolution data on ocean currents and their variations, as well as sea surface height measurements. High-precision ocean altimetry measures the distance between a satellite and the ocean surface to within a few centimeters. Accurate observations of variations in sea surface height (ocean topography) provide scientists with information about the speed and direction of ocean currents and heat stored in the ocean. This information, in turn, reveals global climate variations.
The NODC Ocean Archive System is used to search and retrieve originator datasets and metadata from the NODC archives. Note: The Ocean Archive System searches original datasets as they were submitted to the NODC, not individual points or profiles. Users who wish to search and retrieve ocean profiles or objectively analyzed fields may search through NODC's WODselect (World Ocean Database Select and Search system). Users having trouble finding a particular data set may e-mail the NODC at NODC.Services@noaa.gov, or call at 301-713-3277.
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Data Set Citation
DOC/NOAA/NESDIS/OSDPD > Office of Satellite Data Processing and Distribution, NESDIS, NOAA, U.S. Department of CommerceEUMETSAT > European Meteorological Satellite OrganisationFR/CNES > Centre National d'Etudes Spatiales, France
OSTM/Jason-2 Level-2 Geophysical Data Records
Dataset Release Date:
Dataset Release Place:
World Wide Web
CNES (Centre National d'Etudes Spatiales)
ATTRIBUTE ACCURACY REPORT: The sea surface height shall be provided with a global and ultimate rms accuracy of 3.4 cm (1 sigma) over 1 second averages along JASON-1 ground-tracks for typical sea-state conditions of 2 m SWH and 11 dB sigma-naught. The accuracy on wind speed in IGDR products shall be 1.6 m/s. Near Real Time Altimeter Validation System Reports (NRTAVS) are daily and cover the ... previous 10-day period; distributed through the CLASS system at http://www.nsof.class.noaa.gov/saa/products/
LOGICAL CONSISTENCY REPORT: Instrument calibrations and product quality shall be monitored at least weekly throughout the life of the mission. For each file sent, the Archive performs file validation of the following: file name, file size, and file checksum. CLASS currently performs file name validation. CLASS performs checksum algorithm and routines for additional validation in accordance with the NOAA Environmental Satellite Processing Center (ESPC) to the CLASS Interface Control Document (ICD). OSTM/Jason-2: NRTAVS QA Reports - Quality Reports from the Near Real-Time Altimetry Validation System (NRTAVS). Reports are daily and cover the previous 10-day period; distributed through CLASS at http://www.nsof.class.noaa.gov/saa/products/
COMPLETENESS REPORT: Validation failure will result in placing the file in a hold state. The Access Contact for the Producer will be contacted by CLASS Operations personnel. Information about updates and edits to Jason-2 data is available through CLASS at http://www.class.ncdc.noaa.gov/notification/news.htm#5 Jason-2 IGDR Replaced Data.
HORIZONTAL POSITIONAL ACCURACY REPORT: The orbit maintenance requirements for altimetry missions are usually that the deviation of the actual ground track from the nominal one is kept below 1 km and that the mean local nodal crossing time matches the nominal one to better than to within five minutes. The orbit maintenance strategy aims for minimum disturbance of the payload operation. In-plane manoeuvres are used for altitude adjustment to compensate for the effects of air-drag. This altitude decay controls affects the ground-track repeatability, mainly in the equatorial regions. The frequency of these manoeuvres is determined by the rate of orbital decay, which in turn is determined by the air density, and this is a function of solar activity. The nominal rate for these in-plane manoeuvres is nominally twice a month. They do not interrupt the operations of most sensors. Out-of-plane corrections are used to correct rectify the steady drift of inclination mainly caused by solar and lunar gravity perturbations. The solar wind also influences inclination, but its contribution is typically an order of magnitude smaller than the one given made by solar and lunar gravity. Inclination drift degrades ground-track maintenance at high latitudes. The drift rate does not depend on air density and corrections are required every few months. As they are out-of-plane they require a 90-degree rotation of the spacecraft, to align the thrusters with the required thrust direction, so these manoeuvres will are performed in during eclipse to avoid the risk of optical sensors viewing the sun. The satellites Topex/Poseidon, Jason-1, and Jason-2 (OSTM) carry three tracking systems (DORIS, GPS, and laser telemetry) that enable their position in space (ephemeris) to be determined with an accuracy of +/- 1 cm. The DoRIS system is based on the principle of the Doppler effect. DORIS uses the Doppler shift on the beacon signals to accurately determine the velocity of the satellite on its orbit, and dynamic orbitography models
VERTICAL POSITIONAL ACCURACY REPORT: Please see the horizontal positional report. Specific to OSTM/Jason-2: Orbital information is distributed through CLASS at http://www.nsof.class.noaa.gov/saa/products/. The satellites Topex/Poseidon, Jason-1, and Jason-2 (OSTM) carry three tracking systems (DORIS, GPS, and laser telemetry) that enable their position in space (ephemeris) to be determined with an accuracy of +/- 1 cm. The accuracy on Sea Wave Height in OGDR products shall be respectively 10% or 0.5 m (whichever is greater).
LINEAGE/PROCESS STEP: PROCESS DESCRIPTION: OSTM/Jason-2 is a collaboration between NASA; the National Oceanic and Atmospheric Administration (NOAA); CNES; and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). CNES is providing the spacecraft, NASA and CNES are jointly providing the payload instruments and NASA's Launch Services Program at the Kennedy Space Center is responsible for Delta II launch management and countdown operations. After completing the on-orbit commissioning of the spacecraft, CNES will hand over its operation and control to NOAA. NOAA and EUMETSAT will generate the near-real-time products and distribute them to users. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the mission for NASA's Science Mission Directorate in Washington. There are three levels of processed data: - Telemetry data (raw data or level 0) - Sensor Data Records (engineering units or level 1) - Geophysical Data Records (geophysical units or level 2) Level 1 data and level 2 geophysical data: Level 1 data are corrected for instrument errors, errors due to atmospheric signal propagation and perturbations caused by surface reflection. Geophysical corrections are then applied (solid earth, ocean and pole tides, etc.). Moreover, precise orbit determination (POD) can be performed to provide the highest accuracy. The level 2 geophysical data records derived from instruments aboard the JASON-2 satellite and are available as 3 datatypes: Operational Geophysical Data Records (OGDR), Interim Geophysical Data Records (IGDR) and final Geophysical Data Records (GDR). The OGDRs are near-real-time records and are generated every 3-5 hours. They are based on orbits from DORIS propagator and forecast meteorological fields for the geophysical corrections. The IGDRs are based on preliminary DORIS ephemeris, analyzed meteorological grids, and preliminary auxiliary data files. They have a data latency of 1 - 2 days. The S-IGDR is a superset of the IGDR, containing the original radar echo "waveform" data. The GDRs are based on final high-precision DORIS (perhaps combined with GPS) ephemeris, final meteorological grids, ancillary and auxiliary data files. S-GDR is a superset of the GDR, containing the waveform data. They are generated every 10 days. Sea Surface Height Anomaly (SSHA) files are available for IGDR and GDR. All files are available in NetCDF format and the OGDR is also available in BUFR format.
LINEAGE/PROCESS STEP: PROCESS DESCRIPTION: Quality Reports from the Near Real-Time Altimetry Validation System (NRTAVS). Reports are daily and cover the previous 10-day period. SOURCE USED CITATION ABBREVIATION: Jason-2 GDR SOURCE USED CITATION ABBREVIATION: Jason-2 QA PROCESS DATE: 20081215 PROCESS DATE: 20081215 SOURCE PRODUCED CITATION ABBREVIATION: gov.noaa.class:J2_XGDR SOURCE PRODUCED CITATION ABBREVIATION: gov.noaa.class:J2_QA
LINEAGE/SOURCE INFORMATION: ORIGINATOR: DOC/NOAA/NESDIS/OSDPD/ESPC > Environmental Satellite Processing Center, Office of Satellite Data Processing and Distribution, NESDIS, NOAA, U.S. Department of Commerce .
LINEAGE/SOURCE INFORMATION: ORIGINATOR: EUMETSAT > European Meteorological Satellite Organisation . TITLE: Jason-2 data records . PUBLICATION DATE: 2008-12-15. PUBLICATION PLACE: Silver Spring, MD . PUBLISHER: NOAA National Oceanographic Data Center . GEOSPATIAL DATA PRESENTATION FORM: data files . OTHER CITATION DETAILS: Raw telemetry (level-0) downlinked to the ground stations is forwarded to the quality control and processing centres. Telemetry is then processed to obtain level 1 data, i.e., data that are timed and located, expressed in the appropriate units, and checked for quality. (Jason-2's ground segment is a distributed system between NASA, CNES, Eumetsat and NOAA. On the terms and conditions specified with the quadripartite agreement for the Jason-2 project: Raw data of the Poseidon3 altimeter, DORIS and the radiometer are processed by the NOAA and Eumetsat centres to product near-real time altimetry data (OGDR); Raw data of the Poseidon-3 altimeter and the radiometer are only processed by the mission centre at CNES to product delayed time altimetry data (IGDR; S-IGDR, GDR and S-GDR)). Level 0 and Level 1 satellite altimetry data are of limited usefulness as they have not been processed for precise quality control, and are not typically distributed. Additional Jason-2 data archived at the NODC includes orbital files, level-2 geophysical data (GDR) files, auxiliary files, and documentation. Some of these data may have use restrictions, please contact the NODC or CLASS for more information or check online at the listed URL. ONLINE LINKAGE: http://www.nodc.noaa.gov/archive/arc0023/0043269/ . TYPE OF SOURCE MEDIA: Distributed satellite data files . SOURCE TIME PERIOD OF CONTENT/BEGINNING TIME: 200807 . SOURCE TIME PERIOD OF CONTENT/ENDING TIME: Present . SOURCE CURRENTNESS REFERENCE: ground condition . SOURCE CITATION ABBREVIATION: J2_Level1b . SOURCE CONTRIBUTION: Level-2 GDRs are processed from two levels of data:1) Telemetry data (raw data or level-0) and 2) Sensor Data Records (engineering units or level-1)
ACCESS CONSTRAINTS: None
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DISTRIBUTION LIABILITY: While NODC makes every effort to ensure that its databases are error-free, errors do occur. We ask that you notify us immediately of any errors that you discover in our data. We will make every effort to correct them. With respect to documents available from this server, neither the United States Government nor any of its employees, makes any warranty, express or implied, including the warranties of merchantability and fitness for a particular purpose; nor assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed; nor represents that its use would not infringe privately owned rights.
CUSTOM ORDER PROCESS: A tutorial on ordering data from CLASS is illustrated at http://www.class.ncdc.noaa.gov/release/data_available/jason/jason2t...; users may also contact the NODC directly for assistance at the contact listed in the DISTRIBUTION section of this metadata record. CUSTOM ORDER PROCESS: Please contact the NODC (NODC.Services@noaa.gov) for more information.