Quarterly VLBI EOP Solution opa2011a 1. Purpose of solution: TRF/CRF and EOP series. 2. Analysis center: OPA (Paris Observatory). 3. Short narrative description of solution: The OPA quarterly solution estimates all EOP and rates and station positions/velocities and radio source coordinates. 4. Estimated parameters: a. celestial frame: right ascension, declination (some global, some local). b. terrestrial frame: X, Y, Z, Xdot, Ydot, Zdot (global). c. Earth orientation: x, y, UT1-UTC, xdot, ydot, UT1dot, dX, dY (all local). d. zenith troposphere: continuous piece-wise linear 20-min interval; VMF1 wet partial derivative (segmented). e. troposphere gradients: 8-hour East and North piece-wise continuous at all stations except a set of 105 stations (segmented). AUSTINTX AZORES BERMUDA BLKBUTTE BLOOMIND BREST CARNUSTY CARROLGA \ CHLBOLTN CTVASBAY CTVASTJ DAITO DEADMANL DSS13 DSS65A EFLSBERG \ ELY FLAGSTAF FORT ORD FORTORDS FTD 7900 GIFU11 GIFU3 GOLDMARS \ GOLDVENU GORF7102 GRASSE HALEAKAL HOBART12 HOFN HOHENFRG HOHNBERG \ JPL MV1 KAINAN KANOZAN KARLBURG KASHIM11 KIRSBERG KODIAK KOGANEI \ KOGANEI3 KWAJAL26 LEONRDOK MADRID64 MAMMOTHL MARCUS MCD 7850 METSAHOV \ METSHOVI MIAMI20 MILESMON MIURA MIYAZAKI MIZNAO10 MIZUSGSI MOJ 7288 \ MON PEAK MV2ONSLA NOBEY 6M NOME NRAO 140 NRAO85 1 OCOTILLO OVR 7853 \ PBLOSSOM PENTICTN PINFLATS PLATTVIL PRESIDIO PT REYES PVERDES QUINCY \ ROBLED32 SAGARA SANPAULA SEATTLE1 SEST SHANGHAI SINTOTU SNDPOINT \ SOURDOGH SUWON TATEYAMA TIDBIN64 TIGOWTZL TITIJIMA TOMAKO11 TOULOUSE \ TROMSONO TRYSILNO TSUKU3 TSUKUBA UCHINOUR USSURISK USUDA64 VERAISGK \ VERNAL VICTORIA VLA-N8 WHTHORSE YAKATAGA YEBES YEBES40M YELLOWKN \ YUMA f. station clocks: quadratic + continuous piece-wise linear with 60-min interval (segmented). g. baseline clocks: set in initial analysis - usually used (local). h. other: global antenna axis offsets for 77 stations (global). AIRA ALGOPARK BADARY BR-VLBA CHICHI10 CRIMEA CTVASTJ DSS13 \ DSS15 DSS45 DSS65 EFLSBERG FD-VLBA FORTLEZA GGAO7108 GIFU11 \ GILCREEK HARTRAO HATCREEK HAYSTACK HN-VLBA HOBART12 HOBART26 HRAS 085 \ JPL MV1 KASHIM34 KASHIMA KAUAI KOKEE KP-VLBA KWAJAL26 LA-VLBA \ MARPOINT MATERA MEDICINA METSAHOV MIAMI20 MK-VLBA MOJAVE12 MON PEAK \ NL-VLBA NOTO NRAO20 NRAO85 3 NYALES20 OHIGGINS ONSALA60 OV-VLBA \ OVRO 130 PARKES PENTICTN PIETOWN PINFLATS PLATTVIL PRESIDIO QUINCY \ RICHMOND SANTIA12 SC-VLBA SESHAN25 SINTOTU3 SVETLOE SYOWA TIGOCONC \ TIGOWTZL TSUKUB32 URUMQI VERAISGK VERAMZSW VNDNBERG WESTFORD WETTZELL \ YEBES YEBES40M YLOW7296 YUMA ZELENCHK 5. Celestial reference frame: a. a priori source positions: ICRF2. b. source positions adjusted in solution: yes. If yes, c. definition of orientation: NNR tie to the 295 ICRF2 defining sources. d. source position estimation: mostly global and some local. 6. Terrestrial reference frame: a. a priori station positions: VTRF 2008a. b. a priori station velocities: VTRF 2008a. c. reference epoch for site positions: 2000.01.01. d. station positions/velocities adjusted in solution: yes. If yes, e. definition of origin, orientation, and their time evolution: no-net- translation and no-net-rotation of position and velocity with respect to VTRF 2008a for 35 stations: ALGOPARK BR-VLBA DSS45 FD-VLBA FORTLEZA HARTRAO HATCREEK HAYSTACK \ HN-VLBA HOBART26 KASHIM34 KASHIMA KAUAI KOKEE KP-VLBA LA-VLBA \ MATERA MK-VLBA NL-VLBA NOTO NRAO20 NRAO85_3 NYALES20 ONSALA60 \ OV-VLBA OVRO_130 PIETOWN RICHMOND SANTIA12 SC-VLBA SESHAN25 SVETLOE \ VNDNBERG WESTFORD WETTZELL f. station parameter estimation: X, Y, Z, Xdot, Ydot, Zdot globally for all stations. g. stations with constraints: a priori velocity of U, E, and N components were constrained to the VTRF 2008a velocities with reciprocal weights 0.1, 3.0, and 3.0 mm/yr respectively for stations having too short history of observations, in many cases only one occupation. h. stations with discontinuous positions and date of discontinuity: YAKATAGA 1987.12.01: Earthquake SOURDOGH 1987.12.01: Earthquake WHTHORSE 1987.12.01: Earthquake FORTORDS 1989.10.01: Earthquake PRESIDIO 1989.10.01: Earthquake MOJAVE12 1992.06.27: Earthquake DSS15 1992.06.27: Earthquake MEDICINA 1996.06.01: Rail repair EFLSBERG 1996.10.01: Rail repair DSS65 1997.04.15: Rail repair MIURA 2000.06.01: Earthquake TATEYAMA 2000.06.01: Earthquake GGAO7108 2003.01.01: Station relocation SINTOTU3 2003.09.15: h/z i. stations with nonlinear velocities: GILCREEK, HRAS_085, PIETOWN, TIGOGONC, and TSUKUB32. j. relativity scale: G_oo = -1 + (2W/c^2 + W^2/c^4) - 2L_g G_oa = -4W^a/c^3 G_ab = \delta_ab (1 + 2W/c^2 - 2L_g) k. permanent tide correction: yes. 7. Earth orientation: a. a priori precession model: IAU 2006. b. a priori nutation model: IAU 2006. c. a priori short-period tidal variations in x, y, UT1: IERS 2003. d. EOP estimation: X, Y, UT1, Xdot, Ydot, UT1dot, dX, dY each day. In this solution, the option NUTATION XY_OFFSET is turned on, so that estimated nutation quantities are the celestial pole offsets dX, dY wrt the IAU 2006 precession-nutation (consisting of the IAU 2000A nutation and the P03 precession) using the non-rotating origin-based coordinate transformation between the TRF and the CRF (Capitaine et al. 2003). The .eob file produced by a homemade getpar program contains dX and dY (and NOT dpsi and deps) wrt IAU 2006. Time tag of EOP series is the middle epoch of the observing session. The IERS 2003 model of high frequency variations in polar motion and UT1 was added to the apriori EOP during data reduction. The reported values of polar motion and UT1 are the sum of the adjustments and the apriori EOP without contribution due to the high frequency variations. Thus, the final series of polar motion and UT1 DO NOT contain contributions due to the high frequency variations. 8. A priori geophysical models: a. troposphere: VMF1 mapping function; a priori mean gradients from VLBI data or DAO weather model. b. solid Earth tide: IERS Conventions 1996, p.56-65, step 1 and step 2, anelasticity variant, including tides of the 3-rd order. c. pressure loading: ocean loading displacements computed from FES 2004. Atmospheric loading displacements obtained from the APLO service (Petrov & Boy 2004). d. thermal expansion modeling: model of Nothnagel (2008). 9. Data type: group delays. 10. Data editing: 5 degree elevation cutoff. 11. Data weighting: weights are defined as follows: 1/sqrt ( f**2 + a**2 ) where "f" is the formal uncertainty of the ionosphere free linear combination of group delays at X- and S-band obtained by fringe fitting on the base of achieved signal to noise ratio. Station-dependent parameter "a" was computed for each session by an iterative procedure such that the ratio of the sum of squares of the weighted residuals to the estimate of their mathematical expectation is about unity. 12. Standard errors reported: all errors are derived from least-squares estimation propagated from the data weights and the constraints applied to the troposphere, clock and EOP parameters. 13. Software: CALC 10.0, SOLVE revision date 2010.05.21. 14. Other information: solution is reported at http://ivsopar.obspm.fr.