TITLE: GRACE Technical Note 11 Monthly estimates of C20 from 5 SLR satellites based on GRACE RL06 models. UPDATE HISTORY: Created January 19, 2019 - last month reported is December 2019. NOTES: Please use these estimates to replace the C20 values from the GSM files of the GRACE and GRACE-FO RL06 products only. These estimates are not intended to be used with the GRACE RL05 or earlier products. SPECIAL NOTES: 1) Please note change in format. The first 5 columns are unchanged. Two additional columns are added to indicate the MJD and approximate year of the END of the solution interval. 2) A replacement C20 is only provided for months for which a GRACE or GRACE-FO solution is provided. The beginning date for each 'monthly' solution will match or will be within a few days of the corresponding GRACE epoch. In a number of cases, more days were used for the SLR solution than the corresponding GRACE solution to ensure a robust estimate. 3) For selected 'months', the GRACE solution spans more than one month. in these cases, the SLR estimate was based on approximately the same interval so that the epoch of the SLR estimate was close to the epoch of the GRACE 'monthly' solution. 4) Users looking for a complete regular monthly C20 series are directed to https://grace.jpl.nasa.gov/data/get-data/oblateness/ AUTHORS: M. Cheng & J. Ries Center for Space Research The University of Texas at Austin Email: grace@podaac.jpl.nasa.gov DESCRIPTION: As a convenience to users who wish to use a replacement value for C20, a monthly C20 estimate time series is provided. These estimates are obtained from the analysis of Satellite Laser Ranging (SLR) data to five geodetic satellites: LAGEOS-1 and 2, Starlette, Stella and Ajisai. The background gravity model used in the SLR analysis is consistent with the GRACE Release-06 processing, including the use of the same Atmosphere-Ocean De-aliasing product. Each estimate is valid for the 'month' whose STARTING MJD is provided in the first column. The product value for the C20 harmonic from the GSM-2 file may be replaced by the C20 value given in Column 3 below. This series may be cited as: Cheng, M.K. and J. C. Ries (2017) The unexpected signal in GRACE estimates of C20, J. Geodesy, DOI: 10.1007/s00190-016-0995-5. FORMAT: Column 1: MJD of BEGINNING of solution data span (0 hours) Column 2: Year and fraction of year of BEGINNING of solution data span (approximate) Column 3: Replacement C20 (Use this value instead of value in GSM-2 file) Column 4: Replacement C20 - mean C20 (1.0E-10) Column 5: C20 Sigma (1.0E-10) Column 6: MJD of END of solution data span (0 hours) Column 7: Year and fraction of year of END of solution data span (approximate) Mean C20: -4.8416945732000E-004 All values are normalized in the same sense as the GSM product conventions FORMAT(F7.1,F10.4,E22.13,2F8.4,F8.1,F10.4) PRODUCT: 52365.0 2002.2464 -0.4841693464445E-03 1.1088 0.3789 52395.0 2002.3285 52395.0 2002.3285 -0.4841693839423E-03 0.7338 0.3141 52426.0 2002.4134 52487.0 2002.5804 -0.4841695539997E-03 -0.9668 0.3164 52518.0 2002.6653 52518.0 2002.6653 -0.4841695367361E-03 -0.7942 0.3628 52548.0 2002.7474 52548.0 2002.7474 -0.4841695220603E-03 -0.6474 0.3292 52579.0 2002.8323 52579.0 2002.8323 -0.4841694955987E-03 -0.3828 0.3440 52609.0 2002.9144 52609.0 2002.9144 -0.4841694511530E-03 0.0617 0.3556 52640.0 2003.0000 52640.0 2003.0000 -0.4841694111596E-03 0.4616 0.3660 52671.0 2003.0849 52671.0 2003.0849 -0.4841694222631E-03 0.3506 0.3124 52699.0 2003.1615 52699.0 2003.1615 -0.4841693811858E-03 0.7613 0.2755 52730.0 2003.2464 52730.0 2003.2464 -0.4841694007696E-03 0.5655 0.3646 52760.0 2003.3285 52760.0 2003.3285 -0.4841694119354E-03 0.4538 0.3141 52791.0 2003.4134 52821.0 2003.4956 -0.4841695471392E-03 -0.8982 0.3368 52852.0 2003.5804 52852.0 2003.5804 -0.4841695852588E-03 -1.2794 0.2771 52883.0 2003.6653 52883.0 2003.6653 -0.4841695357461E-03 -0.7843 0.2940 52913.0 2003.7474 52913.0 2003.7474 -0.4841695594780E-03 -1.0216 0.3304 52944.0 2003.8323 52944.0 2003.8323 -0.4841695126190E-03 -0.5530 0.3620 52974.0 2003.9144 52974.0 2003.9144 -0.4841694368697E-03 0.2045 0.3261 53005.0 2004.0000 53005.0 2004.0000 -0.4841694396023E-03 0.1772 0.3175 53036.0 2004.0849 53036.0 2004.0849 -0.4841694378500E-03 0.1947 0.3364 53065.0 2004.1643 53065.0 2004.1643 -0.4841694244137E-03 0.3291 0.3424 53096.0 2004.2491 53096.0 2004.2491 -0.4841693961759E-03 0.6114 0.3993 53126.0 2004.3313 53126.0 2004.3313 -0.4841693903986E-03 0.6692 0.3398 53157.0 2004.4162 53157.0 2004.4162 -0.4841694165964E-03 0.4072 0.4006 53187.0 2004.4983 53187.0 2004.4983 -0.4841695176586E-03 -0.6034 0.3786 53218.0 2004.5832 53218.0 2004.5832 -0.4841695252014E-03 -0.6788 0.3131 53249.0 2004.6680 53249.0 2004.6680 -0.4841695294782E-03 -0.7216 0.3757 53279.0 2004.7502 53279.0 2004.7502 -0.4841694847133E-03 -0.2739 0.3625 53310.0 2004.8350 53310.0 2004.8350 -0.4841694920856E-03 -0.3477 0.3625 53340.0 2004.9172 53340.0 2004.9172 -0.4841693869316E-03 0.7039 0.3959 53371.0 2005.0000 53371.0 2005.0000 -0.4841694222766E-03 0.3504 0.3130 53402.0 2005.0849 53402.0 2005.0849 -0.4841693911623E-03 0.6616 0.3834 53430.0 2005.1615 53430.0 2005.1615 -0.4841693330012E-03 1.2432 0.3837 53461.0 2005.2464 53461.0 2005.2464 -0.4841693173220E-03 1.4000 0.3352 53491.0 2005.3285 53491.0 2005.3285 -0.4841693273691E-03 1.2995 0.3276 53522.0 2005.4134 53522.0 2005.4134 -0.4841693602032E-03 0.9712 0.3270 53552.0 2005.4956 53552.0 2005.4956 -0.4841694752994E-03 -0.1798 0.3075 53583.0 2005.5804 53583.0 2005.5804 -0.4841694929210E-03 -0.3560 0.3196 53614.0 2005.6653 53614.0 2005.6653 -0.4841695264719E-03 -0.6915 0.3421 53644.0 2005.7474 53644.0 2005.7474 -0.4841694830620E-03 -0.2574 0.3202 53675.0 2005.8323 53675.0 2005.8323 -0.4841694718633E-03 -0.1454 0.3695 53705.0 2005.9144 53705.0 2005.9144 -0.4841694272157E-03 0.3010 0.3573 53736.0 2006.0000 53736.0 2006.0000 -0.4841694435805E-03 0.1374 0.3278 53767.0 2006.0849 53767.0 2006.0849 -0.4841694123886E-03 0.4493 0.3647 53795.0 2006.1615 53795.0 2006.1615 -0.4841693943110E-03 0.6301 0.3714 53826.0 2006.2464 53826.0 2006.2464 -0.4841693890904E-03 0.6823 0.3520 53856.0 2006.3285 53856.0 2006.3285 -0.4841694075030E-03 0.4982 0.3137 53887.0 2006.4134 53887.0 2006.4134 -0.4841694043674E-03 0.5295 0.2850 53917.0 2006.4956 53917.0 2006.4956 -0.4841695066079E-03 -0.4929 0.2639 53948.0 2006.5804 53948.0 2006.5804 -0.4841695044186E-03 -0.4710 0.2771 53979.0 2006.6653 53979.0 2006.6653 -0.4841695271240E-03 -0.6980 0.2917 54009.0 2006.7474 54009.0 2006.7474 -0.4841694931552E-03 -0.3584 0.2874 54040.0 2006.8323 54040.0 2006.8323 -0.4841694452194E-03 0.1210 0.3033 54070.0 2006.9144 54070.0 2006.9144 -0.4841694137197E-03 0.4360 0.3086 54101.0 2007.0000 54101.0 2007.0000 -0.4841694682483E-03 -0.1093 0.3091 54132.0 2007.0849 54132.0 2007.0849 -0.4841693813988E-03 0.7592 0.3642 54160.0 2007.1615 54160.0 2007.1615 -0.4841693716473E-03 0.8567 0.2787 54191.0 2007.2464 54191.0 2007.2464 -0.4841693943543E-03 0.6297 0.2977 54221.0 2007.3285 54221.0 2007.3285 -0.4841693713372E-03 0.8598 0.2804 54252.0 2007.4134 54252.0 2007.4134 -0.4841694082228E-03 0.4910 0.2851 54282.0 2007.4956 54282.0 2007.4956 -0.4841695002483E-03 -0.4293 0.3018 54313.0 2007.5804 54313.0 2007.5804 -0.4841695236387E-03 -0.6632 0.2848 54344.0 2007.6653 54344.0 2007.6653 -0.4841695142614E-03 -0.5694 0.3156 54374.0 2007.7474 54374.0 2007.7474 -0.4841695422137E-03 -0.8489 0.3050 54405.0 2007.8323 54405.0 2007.8323 -0.4841695347417E-03 -0.7742 0.3380 54435.0 2007.9144 54435.0 2007.9144 -0.4841694560098E-03 0.0131 0.3540 54466.0 2008.0000 54466.0 2008.0000 -0.4841694795046E-03 -0.2218 0.3459 54497.0 2008.0849 54497.0 2008.0849 -0.4841694559124E-03 0.0141 0.2990 54526.0 2008.1643 54526.0 2008.1643 -0.4841694050421E-03 0.5228 0.3112 54557.0 2008.2491 54557.0 2008.2491 -0.4841693589691E-03 0.9835 0.3369 54587.0 2008.3313 54587.0 2008.3313 -0.4841693882915E-03 0.6903 0.3014 54618.0 2008.4162 54618.0 2008.4162 -0.4841694668615E-03 -0.0954 0.3183 54648.0 2008.4983 54648.0 2008.4983 -0.4841695407709E-03 -0.8345 0.2930 54679.0 2008.5832 54679.0 2008.5832 -0.4841695896078E-03 -1.3229 0.2786 54710.0 2008.6680 54710.0 2008.6680 -0.4841695379895E-03 -0.8067 0.3135 54740.0 2008.7502 54740.0 2008.7502 -0.4841695239234E-03 -0.6660 0.2877 54771.0 2008.8350 54771.0 2008.8350 -0.4841695349115E-03 -0.7759 0.3297 54801.0 2008.9172 54801.0 2008.9172 -0.4841695135090E-03 -0.5619 0.3307 54832.0 2009.0000 54832.0 2009.0000 -0.4841694586329E-03 -0.0131 0.3084 54863.0 2009.0849 54863.0 2009.0849 -0.4841694610104E-03 -0.0369 0.3336 54891.0 2009.1615 54891.0 2009.1615 -0.4841694539342E-03 0.0339 0.3022 54922.0 2009.2464 54922.0 2009.2464 -0.4841694220362E-03 0.3528 0.3214 54952.0 2009.3285 54952.0 2009.3285 -0.4841694427870E-03 0.1453 0.3197 54983.0 2009.4134 54983.0 2009.4134 -0.4841694314731E-03 0.2585 0.3998 55013.0 2009.4956 55013.0 2009.4956 -0.4841695010748E-03 -0.4375 0.3077 55044.0 2009.5804 55044.0 2009.5804 -0.4841695349555E-03 -0.7764 0.3031 55075.0 2009.6653 55075.0 2009.6653 -0.4841695517195E-03 -0.9440 0.3094 55105.0 2009.7474 55105.0 2009.7474 -0.4841694918100E-03 -0.3449 0.3254 55136.0 2009.8323 55136.0 2009.8323 -0.4841695122805E-03 -0.5496 0.3502 55166.0 2009.9144 55166.0 2009.9144 -0.4841694568555E-03 0.0046 0.3613 55197.0 2010.0000 55197.0 2010.0000 -0.4841694196090E-03 0.3771 0.3173 55228.0 2010.0849 55228.0 2010.0849 -0.4841694492871E-03 0.0803 0.3332 55256.0 2010.1615 55256.0 2010.1615 -0.4841694121017E-03 0.4522 0.3120 55287.0 2010.2464 55287.0 2010.2464 -0.4841694561815E-03 0.0114 0.3963 55317.0 2010.3285 55317.0 2010.3285 -0.4841693989410E-03 0.5838 0.3530 55348.0 2010.4134 55348.0 2010.4134 -0.4841694456587E-03 0.1166 0.3611 55378.0 2010.4956 55378.0 2010.4956 -0.4841695796745E-03 -1.2235 0.3448 55409.0 2010.5804 55409.0 2010.5804 -0.4841696115140E-03 -1.5419 0.3004 55440.0 2010.6653 55440.0 2010.6653 -0.4841696045051E-03 -1.4719 0.3018 55470.0 2010.7474 55470.0 2010.7474 -0.4841695986337E-03 -1.4131 0.3131 55501.0 2010.8323 55501.0 2010.8323 -0.4841695395086E-03 -0.8219 0.3207 55531.0 2010.9144 55531.0 2010.9144 -0.4841694683909E-03 -0.1107 0.3658 55562.0 2011.0000 55593.0 2011.0849 -0.4841694630134E-03 -0.0569 0.3644 55621.0 2011.1615 55621.0 2011.1615 -0.4841694817091E-03 -0.2439 0.2902 55652.0 2011.2464 55652.0 2011.2464 -0.4841694822531E-03 -0.2493 0.3544 55682.0 2011.3285 55682.0 2011.3285 -0.4841694663413E-03 -0.0902 0.2814 55713.0 2011.4134 55743.0 2011.4956 -0.4841695930894E-03 -1.3577 0.2990 55774.0 2011.5804 55774.0 2011.5804 -0.4841695921082E-03 -1.3479 0.2879 55805.0 2011.6653 55805.0 2011.6653 -0.4841695727579E-03 -1.1544 0.2778 55835.0 2011.7474 55835.0 2011.7474 -0.4841696132149E-03 -1.5589 0.2913 55866.0 2011.8323 55851.0 2011.7912 -0.4841695915529E-03 -1.3423 0.3071 55881.0 2011.8734 55907.0 2011.9446 -0.4841695657588E-03 -1.0844 0.2924 55937.0 2012.0274 55927.0 2012.0000 -0.4841695822964E-03 -1.2498 0.2990 55958.0 2012.0849 55958.0 2012.0849 -0.4841695546750E-03 -0.9735 0.3038 55987.0 2012.1643 55987.0 2012.1643 -0.4841695208291E-03 -0.6351 0.2782 56018.0 2012.2491 56006.0 2012.2163 -0.4841695007286E-03 -0.4341 0.2992 56036.0 2012.2984 56079.0 2012.4162 -0.4841695575778E-03 -1.0026 0.3101 56109.0 2012.4983 56109.0 2012.4983 -0.4841696556564E-03 -1.9834 0.2622 56140.0 2012.5832 56140.0 2012.5832 -0.4841696466609E-03 -1.8934 0.2725 56171.0 2012.6680 56171.0 2012.6680 -0.4841696393174E-03 -1.8200 0.3054 56201.0 2012.7502 56232.0 2012.8350 -0.4841695694784E-03 -1.1216 0.3523 56262.0 2012.9172 56262.0 2012.9172 -0.4841695834536E-03 -1.2613 0.4000 56293.0 2013.0000 56293.0 2013.0000 -0.4841695293808E-03 -0.7206 0.3285 56324.0 2013.0849 56324.0 2013.0849 -0.4841695487387E-03 -0.9142 0.3238 56352.0 2013.1615 56393.0 2013.2738 -0.4841694736865E-03 -0.1637 0.3060 56413.0 2013.3285 56413.0 2013.3285 -0.4841694738652E-03 -0.1655 0.3038 56444.0 2013.4134 56444.0 2013.4134 -0.4841695101847E-03 -0.5286 0.3165 56474.0 2013.4956 56474.0 2013.4956 -0.4841696422616E-03 -1.8494 0.3073 56505.0 2013.5804 56566.0 2013.7474 -0.4841696235121E-03 -1.6619 0.3106 56597.0 2013.8323 56597.0 2013.8323 -0.4841696242441E-03 -1.6692 0.3453 56627.0 2013.9144 56627.0 2013.9144 -0.4841695166379E-03 -0.5932 0.3253 56658.0 2014.0000 56658.0 2014.0000 -0.4841695485061E-03 -0.9119 0.3048 56689.0 2014.0849 56717.0 2014.1615 -0.4841695157095E-03 -0.5839 0.2921 56748.0 2014.2464 56748.0 2014.2464 -0.4841695099531E-03 -0.5263 0.3069 56778.0 2014.3285 56778.0 2014.3285 -0.4841694905007E-03 -0.3318 0.2993 56809.0 2014.4134 56809.0 2014.4134 -0.4841695488512E-03 -0.9153 0.2839 56839.0 2014.4956 56870.0 2014.5804 -0.4841696337368E-03 -1.7642 0.2918 56901.0 2014.6653 56901.0 2014.6653 -0.4841696760553E-03 -2.1874 0.3282 56931.0 2014.7474 56931.0 2014.7474 -0.4841696455319E-03 -1.8821 0.2994 56962.0 2014.8323 56962.0 2014.8323 -0.4841695708759E-03 -1.1356 0.3168 56992.0 2014.9144 57023.0 2015.0000 -0.4841696084135E-03 -1.5109 0.3547 57054.0 2015.0849 57054.0 2015.0849 -0.4841695287111E-03 -0.7139 0.4129 57082.0 2015.1615 57082.0 2015.1615 -0.4841695274714E-03 -0.7015 0.3051 57113.0 2015.2464 57113.0 2015.2464 -0.4841695353990E-03 -0.7808 0.3163 57143.0 2015.3285 57124.0 2015.2765 -0.4841695203166E-03 -0.6300 0.2651 57154.0 2015.3587 57204.0 2015.4956 -0.4841696340685E-03 -1.7675 0.2874 57235.0 2015.5804 57235.0 2015.5804 -0.4841696597474E-03 -2.0243 0.2810 57266.0 2015.6653 57266.0 2015.6653 -0.4841696537363E-03 -1.9642 0.3110 57296.0 2015.7474 57362.0 2015.9281 -0.4841695296394E-03 -0.7232 0.2729 57393.0 2016.0137 57388.0 2016.0000 -0.4841695285985E-03 -0.7128 0.3940 57419.0 2016.0849 57419.0 2016.0849 -0.4841694695182E-03 -0.1220 0.2751 57448.0 2016.1643 57448.0 2016.1643 -0.4841695043479E-03 -0.4703 0.3372 57479.0 2016.2491 57509.0 2016.3313 -0.4841694839000E-03 -0.2658 0.3394 57540.0 2016.4162 57540.0 2016.4162 -0.4841695349363E-03 -0.7762 0.3603 57570.0 2016.4983 57570.0 2016.4983 -0.4841696507098E-03 -1.9339 0.3725 57601.0 2016.5832 57601.0 2016.5832 -0.4841696457497E-03 -1.8843 0.3155 57632.0 2016.6680 57705.0 2016.8679 -0.4841695428547E-03 -0.8553 0.3176 57732.0 2016.9418 57733.0 2016.9446 -0.4841695182314E-03 -0.6091 0.3282 57759.0 2017.0137 57760.0 2017.0164 -0.4841695591986E-03 -1.0188 0.3049 57787.0 2017.0903 57829.0 2017.2053 -0.4841695534330E-03 -0.9611 0.3327 57857.0 2017.2820 57853.0 2017.2710 -0.4841695179447E-03 -0.6062 0.2869 57881.0 2017.3477 57874.0 2017.3285 -0.4841695158384E-03 -0.5852 0.3027 57904.0 2017.4107 57896.0 2017.3888 -0.4841694719537E-03 -0.1463 0.2539 57933.0 2017.4901 58270.0 2018.4134 -0.4841695134825E-03 -0.5616 0.4176 58300.0 2018.4956 58300.0 2018.4956 -0.4841696496806E-03 -1.9236 0.3675 58331.0 2018.5804 58413.0 2018.8049 -0.4841696472474E-03 -1.8993 0.3053 58431.0 2018.8542 58423.0 2018.8323 -0.4841695952520E-03 -1.3793 0.4544 58453.0 2018.9144 58453.0 2018.9144 -0.4841695786428E-03 -1.2132 0.4706 58484.0 2019.0000 58484.0 2019.0000 -0.4841695669065E-03 -1.0959 0.4315 58515.0 2019.0849 58509.0 2019.0684 -0.4841695317334E-03 -0.7441 0.4219 58548.0 2019.1752 58543.0 2019.1615 -0.4841695449796E-03 -0.8766 0.3312 58574.0 2019.2464 58574.0 2019.2464 -0.4841694877166E-03 -0.3040 0.3169 58604.0 2019.3285 58604.0 2019.3285 -0.4841695018010E-03 -0.4448 0.3659 58635.0 2019.4134 58635.0 2019.4134 -0.4841695496504E-03 -0.9233 0.4319 58665.0 2019.4963 58665.0 2019.4956 -0.4841696929991E-03 -2.3568 0.3813 58696.0 2019.5812 58696.0 2019.5804 -0.4841696664659E-03 -2.0915 0.3739 58727.0 2019.6662 58727.0 2019.6653 -0.4841697073407E-03 -2.5002 0.3547 58757.0 2019.7483 58757.0 2019.7474 -0.4841697005154E-03 -2.4320 0.3769 58788.0 2019.8333 58788.0 2019.8323 -0.4841695932084E-03 -1.3589 0.4151 58818.0 2019.9155 58818.0 2019.9144 -0.4841695721554E-03 -1.1484 0.5115 58849.0 2020.0000