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Geoid variations observed over South America that can be largely attributed to surface water and groundwater changes show a clear separation between the large Amazon watershed and the smaller watersheds to the north. Such observations will help hydrologists to connect processes at traditional length scales (tens of kilometers or less) to those at regional and global scales.<\/jats:p>","DOI":"10.1126\/science.1099192","type":"journal-article","created":{"date-parts":[[2004,7,22]],"date-time":"2004-07-22T20:38:37Z","timestamp":1090528717000},"page":"503-505","source":"Crossref","is-referenced-by-count":2222,"title":["GRACE Measurements of Mass Variability in the Earth System"],"prefix":"10.1126","volume":"305","author":[{"given":"Byron D.","family":"Tapley","sequence":"first","affiliation":[{"name":"Center for Space Research, University of Texas, Austin, TX 78712, USA."},{"name":"Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Srinivas","family":"Bettadpur","sequence":"additional","affiliation":[{"name":"Center for Space Research, University of Texas, Austin, TX 78712, USA."},{"name":"Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John C.","family":"Ries","sequence":"additional","affiliation":[{"name":"Center for Space Research, University of Texas, Austin, TX 78712, USA."},{"name":"Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul F.","family":"Thompson","sequence":"additional","affiliation":[{"name":"Center for Space Research, University of Texas, Austin, TX 78712, USA."},{"name":"Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael M.","family":"Watkins","sequence":"additional","affiliation":[{"name":"Center for Space Research, University of Texas, Austin, TX 78712, USA."},{"name":"Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","unstructured":"National Research Council Satellite Gravity and the Geosphere (National Academies Press Washington DC 1997)."},{"key":"e_1_3_1_3_2","doi-asserted-by":"publisher","DOI":"10.1029\/2004GL019920"},{"key":"e_1_3_1_4_2","first-page":"3031","volume":"108","year":"2003","unstructured":"S. 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The GRACE mission consists of two identical satellites in near-circular orbits at \u223c500 km altitude separated from each other by \u223c220 km along-track and linked by a highly accurate intersatellite K-band microwave ranging system. Each satellite carries Global Positioning System (GPS) receivers and attitude sensors and high-precision accelerometers to measure the surface forces. Through the dynamical evolution of the orbits the intersatellite distance change (which is extracted from phase measurements of the K-band signal transmitted between the two satellites) contains implicitly the influence of the globally integrated mass distribution and its movements within the Earth system."},{"key":"e_1_3_1_19_2","first-page":"L06619","volume":"31","year":"2004","unstructured":"P. F. Thompson, S. V. Bettadpur, B. D. Tapley, Geophys. Res. Lett.31, L06619 (2004).","journal-title":"Geophys. Res. Lett."},{"key":"e_1_3_1_20_2","unstructured":"T. Gruber T. Peters in IERS Technical Note No. 30 B. Richter W. Schwegmann W. Dick Eds. (Verlag des Bundesamts f\u00fcr Kartographie und Geod\u00e4sie Frankfurt 2003) pp. 157\u2013160 (www.iers.org\/iers\/publications\/tn\/tn30)."},{"key":"e_1_3_1_21_2","unstructured":"Data processing standards and a user handbook for the monthly gravity solutions are available at www.csr.utexas.edu\/grace\/publications\/handbook."},{"key":"e_1_3_1_22_2","doi-asserted-by":"publisher","DOI":"10.1175\/BAMS-85-3-381"},{"key":"e_1_3_1_23_2","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/0022-1694(95)02965-6","volume":"184","year":"1996","unstructured":"D. Entekhabi, I. Rodriguez-Iturbe, F. Castelli, J. Hydrol.184, 3 (1996).","journal-title":"J. Hydrol."},{"key":"e_1_3_1_24_2","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/S0921-8181(98)00047-2","volume":"19","year":"1998","unstructured":"A. Robocket al., Global Planet. Change19, 181 (1998).","journal-title":"Global Planet. 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Jekeli Alternative Methods to Smooth the Earth's Gravity Field (Department of Geodetic Science and Surveying Ohio State University Columbus OH 1981)."},{"key":"e_1_3_1_30_2","unstructured":"See supporting text at Science Online."},{"key":"e_1_3_1_31_2","first-page":"2193","volume":"107","year":"2002","unstructured":"S. Swenson, J. Wahr, J. Geophys. Res.107, 2193 (2002).","journal-title":"J. Geophys. Res."},{"key":"e_1_3_1_32_2","unstructured":"We thank M. Rodell for providing terrestrial water storage output from the GLDAS model T. Pekker and J. Chen for conversion of the GLDAS output into geopotential coefficients and W. Bertiger F. Flechtner B. Gunter Z. Kang G. Kruizinga P. Nagel R. Pastor S. Poole L. Romans H.-J. Rim S.-C. Wu S. Yoon and D.-N. Yuan for their vital contributions to the software development algorithm testing and data processing required to accomplish these results. Supported by NASA contract NAS5-97213."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.1099192","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,10]],"date-time":"2024-01-10T01:52:39Z","timestamp":1704851559000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.1099192"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,7,23]]},"references-count":31,"journal-issue":{"issue":"5683","published-print":{"date-parts":[[2004,7,23]]}},"alternative-id":["10.1126\/science.1099192"],"URL":"https:\/\/doi.org\/10.1126\/science.1099192","relation":{},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,7,23]]}}}