***************************************************************************= *** dorisreport 23-Mar-2020 19:51:46 Message No 4992 ***************************************************************************= *** Author: "Lemoine, Frank G. (GSFC-61A0)" Subject: Submission of gscwd35 solution to the IDS Data Centers. Authors: F.G. Lemoine (Frank.G.Lemoine@nasa.gov) D.S. Chinn (Douglas.S.Chinn@nasa.gov) N.P. Zelensky (nzelensk@umd.edu) As part of the reprocessing associated with ITRF2020, we have submitted a test solution, gscwd35. The solution represents the first stage of our reprocessing of DORIS data, with further improvements yet to come. This series represents a complete reprocessing of all DORIS data from November 1992 to December 2019. The first delivery includes 1417 weekly SINEX files (Earth Orientation Parmeters and Station Coordinates) from 1992-DOY0313 to 2019-DOY0363. The following satellites were processed: SPOT-2, SPOT-3, SPOT-4, SPOT-5, TOPEX/Poseidon, Jason-1, Jason-2, Jason-3, Envisat, HY-2A, Cryosat-2, Saral. For SPOT-5: we use the SAA-corrected data starting in 2006 until the end of mission: For Jason-1: we use the SAA-corrected data only from November 2004 to July 2008. For Jason-2 & Jason-3: we downweight and adjust locally the SAA stations, so they do not contribute to the common solution. For Jason-3: we use RINEX data rather than the DORIS/V2 data. This series supercedes all previous series: As far as processing, models, and software the pertinent features of this series are: 1. All data have been rigorously re-editted using DPOD2014v04 (distributed in September 2019). DPOD2014v04 was modified so that station validity intervals minimized gaps, except for data or station problems. We preferred to err on the side of including data rather than deleting data and a contributing station. Data editing is implemented in two steps: (a) In a first step using an internal GSFC program called "RESPAC" to eliminate the gross outliers. (b) In a second step we use another internal GSFC program to remove outliers. We also remove passes that have too few points, or do not rise above a max elevation of 13 degrees. 2. The versions of GEODYN used included "giis/giie1810" and "giis/giie1906". This versions of GEODYN include more rigorous modeling of station range-rate and troposphere biases. Practically this requires explicit specification of the biases and a much larger normal matrix for weekly POD solutions. We exploit matrix sparseness, for the arc-by-arc bias determination, adapting a procedure used in GPS POD in GEODYN to minimize the impact on program time execution. 3. The major model changes include a new static and time-variable gravity model as apriori (GOCO05s); updated ocean tide model (GOT4p10c); updated non-conservative modelling for different satellites; use of the GFZ RL06 (GRACE-FO-provided) dealiasing products; New model of linear mean pole recommended by the IERS; Use of VMF-1 to as a priori troposphere refraction correction (Boehm and Schuh, 2004): A wet-delay correction is still adjusted per pa= ss. 4. Model Summary: -Static Gravity field: GOCO05s Post-2003.0: GOCO05s Pre-2003.0: GOCO05s propagated with GOCO05s TVG terms from 2008.0 to 2003.0 -C21,S21: Modelled per IERS Conventions (using C20, C22 & model for the linear mean pole): No GOCO05S terms applied. -Time-variable Gravity field: Post-2003.0: GOCO05s annual and secular terms Pre-2003.0: GOCO05s annual terms only -Atmosphere-Ocean Dealiasing (forward modelling of high-frequency gravity variations) GFZ-RL06 (90x90, 3hr): Dobslaw et al. (2017). -Air Tides: Removed from Atmospheric gravity applied externally per Dobslaw et al. (2017). -Ocean Tides: GOT4p10c (20x20) -Earth Tides: IERS2010 (Correcting some errors in the GEODYN implementation from earlier series) -pole tide: Applied -Ocean pole tide: Applied (Desai, 2002) -Tidal Variations in Earth Orientation Parameters: Follows IERS2010 Conventions. -Ocean Loading: GOT4p10c -Atmosphere, Hydrology, and Ocean non-tidal loading: Not applied. -Nonconservative Force Modeling: +direct solar radiation applied, with macromodels +albedo/thermal IR: Knocke et al. (1988) (unchanged from previous series). +atmospheric drag: MSIS86 (unchanged from previous series). +macromodels TOPEX: Improvement to Marshall & Luthcke (1994) SPOT4, SPOT5: CNES macromodel (re-tuned). (Le Bail et al., 2010) (Lemoine et al., 2016) SPOT2, SPOT3 Modified GSFC (tuned) ENVISAT University College London Model (SRP and thermal radiation) 10-plate macromodel (drag, albedo/IR) JASON-1 -Macromodel retuned. JASON-2 -CNES Macromodel, Retuned. (Update to Zelensky et al., 2010) JASON-3 -CNES Macromodel, Retuned. CRYOSAT-2 -CNES Macromodel. HY-2A -CNES Provided model, retuned. SARAL (Zelensky et al., 2016). +attitude models TOPEX: -GEODYN Internal Model. -S/C Quaternions for ~1 percent of arcs. Jason-1, Jason-2, Jason-3: Spacecraft and solar array Quaternions. SPOT satellites: -GEODYN Internal Model. SARAL -GEODYN Internal Model. HY-2A -GEODYN Internal Model. ENVISAT -GEODYN Internal Model. -Empirical Accelerations: Estimated once/daily + OPR (cosine + sine) along-track + OPR (cosine + sine) cross-track -Third body Attraction: Sun, Earth's Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune from JPL's DE421 and DE430. -relativistic effects + force model: point mass, Lense-Thirring. + meaurement model: Moyer (1981); relativistic light time. -Troposphere Model + Mapping function, dry, wet delays from VMF-1, (Boehm and Schuh, 2004). -Annual Earth geocenter Model:=20=20=20=20 Forward modelled per Ries (2016) -Tidal Geocenter Variations: Modelled per GOT4p10. =20=20=20=20=20=20=20 -data corrections: + SAA models used for Jason-1, SPOT-5 (Capdeville et al. 2016) + Antenna Phase Law applied for DORIS antennae (Alcatel, Starec B and Starec C) + Offset corrections:=20=20 +Apply tracking point offset corrections in GEODYN. Generally a priori values from Cerri et al., (2019). +HY-2A C.M. Corrections: DORISMAIL 1092, Dec. 7, 2017, 16:11:16, "HY-2A POD instrument location updates", by Alexandre Couhert +SARAL C.M. Updated per Zelensky et al. (2016). Please do not reply directly to this message, but send comments and suggestions to IDS.central.bureau@cls.fr