GRACE Technical Note 05 TITLE: Monthly estimates of C20 from 5 SLR satellites UPDATE HISTORY: Updated June 12, 2012 - last month reported is April 2012. An error in the year assigned to the last value was corrected. The MJD, corresponding to March 20, 2012, was correct. April 2012 will be the last update to TN05; all future updates will be based on the Release-05 models and provided in GRACE Technical Note 07. SPECIAL NOTES: 1) The GRACE gravity solution from CSR for 'November 2011' actually spans October 17, 2011 to November 16, 2011, due to the lack of useful accelerometer data in the latter half of November. A replacement value of C20 is provided for this special solution (denoted by *) as well as for the full calendar month of November 2011. 2) The GRACE gravity solution from CSR for 'December 2011' actually spans December 12, 2011 to January 11, 2012, due to the lack of useful accelerometer data in the first half of December. A replacement value of C20 is provided for this special solution (denoted by *) as well as for the full calendar month of December 2011. 3) The GRACE gravity solution from CSR for 'April 2012' actually spans March 20, 2012 to April 19, 2012, due to the lack of useful accelerometer data in the latter half of April. A replacement value of C20 is provided for this special solution (denoted by *). 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-04 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. and Tapley, B.D., "Variations in the Earth's oblateness during the past 28 years", Jour Geophys Res v109, B9, Sep 10, 2004. This file will be regularly updated with estimates for the latest months. FORMAT: Column 1: MJD of BEGINNING of month Column 2: Year and fraction of year of BEGINNING of month Column 3: Replacement C20 (Use this value instead of value in GSM-2 file) Column 4: Replacement C20 - reference C20 (1.0E-10) Column 5: C20 Sigma (1.0E-10) Reference C20: -0.48416948E-03 All values are normalized in the same sense as the GSM product conventions FORMAT(F7.1,F10.4,E22.13,2F8.4) PRODUCT: 52275.0 2002.0000 -0.4841694425181E-03 0.3748 0.2723 52306.0 2002.0849 -0.4841694265483E-03 0.5345 0.2563 52334.0 2002.1615 -0.4841694008316E-03 0.7917 0.2342 52365.0 2002.2464 -0.4841693426999E-03 1.3730 0.3266 52395.0 2002.3285 -0.4841693929676E-03 0.8703 0.2720 52426.0 2002.4134 -0.4841693985249E-03 0.8148 0.2822 52456.0 2002.4956 -0.4841695338340E-03 -0.5383 0.2753 52487.0 2002.5804 -0.4841695708282E-03 -0.9083 0.2578 52518.0 2002.6653 -0.4841695564300E-03 -0.7643 0.3195 52548.0 2002.7474 -0.4841695062217E-03 -0.2622 0.2641 52579.0 2002.8323 -0.4841694736500E-03 0.0635 0.2882 52609.0 2002.9144 -0.4841694303369E-03 0.4966 0.3202 52640.0 2003.0000 -0.4841694642891E-03 0.1571 0.2639 52671.0 2003.0849 -0.4841694564619E-03 0.2354 0.2586 52699.0 2003.1615 -0.4841693806304E-03 0.9937 0.2439 52730.0 2003.2464 -0.4841694042851E-03 0.7571 0.2934 52760.0 2003.3285 -0.4841693929284E-03 0.8707 0.2609 52791.0 2003.4134 -0.4841694114219E-03 0.6858 0.2375 52821.0 2003.4956 -0.4841695460098E-03 -0.6601 0.3077 52852.0 2003.5804 -0.4841695992510E-03 -1.1925 0.2545 52883.0 2003.6653 -0.4841695620719E-03 -0.8207 0.2297 52913.0 2003.7474 -0.4841695696268E-03 -0.8963 0.2839 52944.0 2003.8323 -0.4841695198454E-03 -0.3985 0.3236 52974.0 2003.9144 -0.4841694830751E-03 -0.0308 0.2809 53005.0 2004.0000 -0.4841694779359E-03 0.0206 0.2754 53036.0 2004.0849 -0.4841694572915E-03 0.2271 0.2803 53065.0 2004.1643 -0.4841694424091E-03 0.3759 0.3024 53096.0 2004.2491 -0.4841694090132E-03 0.7099 0.3435 53126.0 2004.3313 -0.4841694017495E-03 0.7825 0.2994 53157.0 2004.4162 -0.4841694409605E-03 0.3904 0.3469 53187.0 2004.4983 -0.4841695470337E-03 -0.6703 0.3926 53218.0 2004.5832 -0.4841695597722E-03 -0.7977 0.2523 53249.0 2004.6680 -0.4841695314044E-03 -0.5140 0.3329 53279.0 2004.7502 -0.4841694805225E-03 -0.0052 0.2952 53310.0 2004.8350 -0.4841695106230E-03 -0.3062 0.3036 53340.0 2004.9172 -0.4841694190011E-03 0.6100 0.3195 53371.0 2005.0000 -0.4841694529452E-03 0.2705 0.2452 53402.0 2005.0849 -0.4841694443754E-03 0.3562 0.3558 53430.0 2005.1615 -0.4841693653585E-03 1.1464 0.3077 53461.0 2005.2464 -0.4841693528450E-03 1.2716 0.2805 53491.0 2005.3285 -0.4841693721708E-03 1.0783 0.2608 53522.0 2005.4134 -0.4841693819826E-03 0.9802 0.2691 53552.0 2005.4956 -0.4841695000755E-03 -0.2008 0.2599 53583.0 2005.5804 -0.4841695353259E-03 -0.5533 0.2589 53614.0 2005.6653 -0.4841695400233E-03 -0.6002 0.2643 53644.0 2005.7474 -0.4841695022967E-03 -0.2230 0.2567 53675.0 2005.8323 -0.4841695124109E-03 -0.3241 0.2994 53705.0 2005.9144 -0.4841694619653E-03 0.1803 0.2847 53736.0 2006.0000 -0.4841694748992E-03 0.0510 0.2777 53767.0 2006.0849 -0.4841694539311E-03 0.2607 0.2956 53795.0 2006.1615 -0.4841694452804E-03 0.3472 0.2954 53826.0 2006.2464 -0.4841694518843E-03 0.2812 0.2970 53856.0 2006.3285 -0.4841694140319E-03 0.6597 0.2739 53887.0 2006.4134 -0.4841694085703E-03 0.7143 0.2357 53917.0 2006.4956 -0.4841695341589E-03 -0.5416 0.2263 53948.0 2006.5804 -0.4841695688403E-03 -0.8884 0.2369 53979.0 2006.6653 -0.4841695410748E-03 -0.6107 0.2438 54009.0 2006.7474 -0.4841695083633E-03 -0.2836 0.2413 54040.0 2006.8323 -0.4841694731976E-03 0.0680 0.2736 54070.0 2006.9144 -0.4841694102346E-03 0.6977 0.2753 54101.0 2007.0000 -0.4841693620861E-03 1.1791 0.2623 54132.0 2007.0849 -0.4841694051649E-03 0.7484 0.3367 54160.0 2007.1615 -0.4841693860674E-03 0.9393 0.2438 54191.0 2007.2464 -0.4841694431648E-03 0.3684 0.2702 54221.0 2007.3285 -0.4841694215049E-03 0.5850 0.2430 54252.0 2007.4134 -0.4841694394436E-03 0.4056 0.2604 54282.0 2007.4956 -0.4841695272857E-03 -0.4729 0.3142 54313.0 2007.5804 -0.4841696055919E-03 -1.2559 0.2631 54344.0 2007.6653 -0.4841695454502E-03 -0.6545 0.2791 54374.0 2007.7474 -0.4841695918638E-03 -1.1186 0.2780 54405.0 2007.8323 -0.4841695700254E-03 -0.9003 0.3031 54435.0 2007.9144 -0.4841695111055E-03 -0.3111 0.3235 54466.0 2008.0000 -0.4841693856587E-03 0.9434 0.3269 54497.0 2008.0849 -0.4841695090933E-03 -0.2909 0.2563 54526.0 2008.1643 -0.4841694617220E-03 0.1828 0.2697 54557.0 2008.2491 -0.4841694279114E-03 0.5209 0.3648 54587.0 2008.3313 -0.4841694684682E-03 0.1153 0.3171 54618.0 2008.4162 -0.4841694785346E-03 0.0147 0.3238 54648.0 2008.4983 -0.4841695727096E-03 -0.9271 0.3134 54679.0 2008.5832 -0.4841696054839E-03 -1.2548 0.2503 54710.0 2008.6680 -0.4841695664074E-03 -0.8641 0.3192 54740.0 2008.7502 -0.4841695502504E-03 -0.7025 0.2695 54771.0 2008.8350 -0.4841695134689E-03 -0.3347 0.2529 54801.0 2008.9172 -0.4841694991155E-03 -0.1912 0.2701 54832.0 2009.0000 -0.4841693836689E-03 0.9633 0.2942 54863.0 2009.0849 -0.4841694709599E-03 0.4904 0.2743 54891.0 2009.1615 -0.4841695119101E-03 0.0809 0.2986 54922.0 2009.2464 -0.4841694903522E-03 -0.1035 0.3153 54952.0 2009.3285 -0.4841694878858E-03 -0.0789 0.3206 54983.0 2009.4134 -0.4841695098709E-03 -0.2987 0.4214 55013.0 2009.4956 -0.4841695903354E-03 -1.1034 0.3198 55044.0 2009.5804 -0.4841695730651E-03 -0.9307 0.3010 55075.0 2009.6653 -0.4841695852126E-03 -1.0521 0.3122 55105.0 2009.7474 -0.4841695157727E-03 -0.3577 0.3072 55136.0 2009.8323 -0.4841695136433E-03 -0.3364 0.3453 55166.0 2009.9144 -0.4841694794992E-03 0.0050 0.3997 55197.0 2010.0000 -0.4841694682856E-03 0.1171 0.3512 55228.0 2010.0849 -0.4841694931419E-03 -0.1314 0.3778 55256.0 2010.1615 -0.4841694377747E-03 0.4223 0.2956 55287.0 2010.2464 -0.4841694633484E-03 0.1665 0.3706 55317.0 2010.3285 -0.4841694244640E-03 0.5554 0.3582 55348.0 2010.4134 -0.4841694466682E-03 0.3333 0.3656 55378.0 2010.4956 -0.4841695767282E-03 -0.9673 0.3411 55409.0 2010.5804 -0.4841696158774E-03 -1.3588 0.3010 55440.0 2010.6653 -0.4841696268998E-03 -1.4690 0.3291 55470.0 2010.7474 -0.4841696056521E-03 -1.2565 0.3354 55501.0 2010.8323 -0.4841695580179E-03 -0.7802 0.3478 55531.0 2010.9144 -0.4841695280215E-03 -0.4802 0.4425 55562.0 2011.0000 -0.4841695522219E-03 -0.7222 0.3460 55593.0 2011.0849 -0.4841695153315E-03 -0.3533 0.3959 55621.0 2011.1615 -0.4841695149662E-03 -0.3497 0.3041 55652.0 2011.2464 -0.4841695311160E-03 -0.5112 0.3730 55682.0 2011.3285 -0.4841695330692E-03 -0.5307 0.2972 55713.0 2011.4134 -0.4841695224736E-03 -0.4247 0.3238 55743.0 2011.4956 -0.4841696112239E-03 -1.3122 0.3420 55774.0 2011.5804 -0.4841696030472E-03 -1.2305 0.3083 55805.0 2011.6653 -0.4841696066921E-03 -1.2669 0.3035 55835.0 2011.7474 -0.4841696196161E-03 -1.3962 0.3350 55851.0 2011.7912 -0.4841695822274E-03 -1.0223 0.3925 * 55866.0 2011.8323 -0.4841695680528E-03 -0.8805 0.3729 55896.0 2011.9144 -0.4841695679571E-03 -0.8796 0.4664 55907.0 2011.9446 -0.4841695900015E-03 -1.1000 0.4030 * 55927.0 2012.0000 -0.4841696218418E-03 -1.4184 0.3415 55958.0 2012.0849 -0.4841696062245E-03 -1.2622 0.3550 55987.0 2012.1643 -0.4841695653778E-03 -0.8538 0.3181 56006.0 2012.2190 -0.4841695813378E-03 -1.0134 0.3293 *