***************************************************************************= *** dorisreport 09-Jul-2019 19:38:38 Message No 4791 ***************************************************************************= *** Author: "Lemoine, Frank G. (GSFC-61A0)" Subject: Deliver of SINEX series updates, gscwd32, gscwd33, gscwd34 Dear Colleagues. The GSC/DORIS analysis center has delivered the following SINEX series upda= tes to the NASA CDDIS, and we confirm its successful upload. The delivery includes SINEX files from January 2016 to March 2019. The seri= es have the following attributes: Wd31 =3D Current baseline operational series: itrf2014 stations, Jason-3 SA= A Strategy applied.=20 Wd32 =3D wd31 with update for strategy of estimating troposphere and range-= rate biases. Wd33 =3D wd32 with Jason-2 SAA strategy applied. Wd34 =3D wd32 excluding all J2 and all J3 In principle gscwd33 should become the operational series, until further up= dates are made. The next update we envisage would be a reprocessing, so we can include the new stations that came on line in late 2017 through early 2019. This is indispensable in order to make sure the newer stations are included in further IDS Combination updates. We deliver the above series (wd32, wd33, wd34) as per the request of the IDS Combination Center and IDS Analysis Coordinators to support the ITRF2020 reprocessing and validation of the processing strategies. Now a few words about the update from gscwd31 to gscwd32. As we have described at the IDS AWG meeting in Munich (April 2019), our POD= software (GEODYN) has been updated to update a more mathemathically rigorous estima= tion of troposphere and range-rate biases. In addition, the reprocessing will eliminate very short passes with few poi= nts (four or fewer). So it means sometimes slightly fewer observations in a given arc. Without bori= ng you with arcane and sacred mysteries of the GEODYN code, the change will make future work = easier, especially for the GEODYN code software developers, as well as for the users. We rigorously evaluated the new bias estimation strategy in a number of way= s. The Average SLR fits (for SLR+DORIS arcs) processing are listed below: Satellite Time Span gscwd31 processing gscwd32 processing Avg. SLR fits = Avg. SLR fits. Cryosat2 2010-2019 1.17 cm 1.17 cm HY-2A 2011-2019 1.45 cm 1.36 cm Jason-2 2008-2019 1.10 cm 1.09 cm Jason-3 2016-2019 1.23 cm 1.21 cm Saral 2013-2019 1.348 cm 1.353 cm In terms of WRMS, we note from 2016 to 2018.0, a degradation in the WRMS of about 1mm; Therafter, the change in WRMS is negligible. In terms of the number of stations, both series, wd31, wd32 have the same number of stations. In terms of scale, we find the gscwd32 scale (wrt. ITRF2014/DPOD2014) has shifted downward, a few mm compared to gscwd31. The addition of the SAA strategy to Jason-2 has appeared to not significantly impact the scale. In contrast, removing both Jason-2 & Jason-3 shifts the scale generally by about + 5 mm. We find that the WRMS of the different series (2016-2019) are as follows wd31: 9.347 cm wd32: 9.719 cm wd33: 9.947 cm wd34: 10.856 cm We are happy to answer any questions. Our plans will be to make gscwd33 the basis of any further operational improvements, pending the evaluation by the IDS CC. Sincerely, Frank Lemoine & Doug Chinn Geodesy & Geophysics Laboratory NASA Goddard Space Flight Center Please do not reply directly to this message, but send comments and suggestions to IDS.central.bureau@cls.fr