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   <identifier identifierType="DOI">10.5880/isg.2021.006</identifier>
   <creators>
      <creator>
         <creatorName nameType="Personal">de Matos, Ana Cristina Oliveira Cancoro</creatorName>
         <givenName>Ana Cristina Oliveira Cancoro</givenName>
         <familyName>de Matos</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0002-0040-588X</nameIdentifier>
         <affiliation>Centro de Estudos de Geodesia (CENEGEO), São Paulo, Brazil</affiliation>
      </creator>
      <creator>
         <creatorName nameType="Personal">Blitzkow, Denizar</creatorName>
         <givenName>Denizar</givenName>
         <familyName>Blitzkow</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0003-1412-3063</nameIdentifier>
         <affiliation>Escola Politécnica da Universidade de São Paulo (EPUSP) and Centro de Estudos de Geodesia (CENEGEO), São Paulo, Brazil</affiliation>
      </creator>
      <creator>
         <creatorName nameType="Personal">Guimarães, Gabriel do Nascimento</creatorName>
         <givenName>Gabriel do Nascimento</givenName>
         <familyName>Guimarães</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0003-4380-4650</nameIdentifier>
         <affiliation>Instituto de Geografia, Universidade Federal de Uberlândia (UFU), Uberlândia, Brazil</affiliation>
      </creator>
      <creator>
         <creatorName nameType="Personal">Silva, Valéria Cristina</creatorName>
         <givenName>Valéria Cristina</givenName>
         <familyName>Silva</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0003-1499-6956</nameIdentifier>
         <affiliation>Escola Politécnica da Universidade de São Paulo (EPUSP), São Paulo, Brazil</affiliation>
      </creator>
   </creators>
   <titles>
      <title>The South American gravimetric geoid: GEOID2021</title>
   </titles>
   <publisher>GFZ Data Services</publisher>
   <publicationYear>2021</publicationYear>
   <subjects>
      <subject>Geodesy</subject>
      <subject>Geoid model</subject>
      <subject>ISG</subject>
      <subject>Fast Fourier Transform</subject>
      <subject>South America</subject>
      <subject subjectScheme="NASA/GCMD Earth Science Keywords">EARTH SCIENCE &gt; SOLID EARTH &gt; GEODETICS &gt; GEOID CHARACTERISTICS</subject>
      <subject subjectScheme="NASA/GCMD Earth Science Keywords">EARTH SCIENCE &gt; SOLID EARTH &gt; GRAVITY/GRAVITATIONAL FIELD &gt; GRAVITY</subject>
   </subjects>
   <contributors>
      <contributor contributorType="DataCurator">
         <contributorName nameType="Personal">Reguzzoni, Mirko</contributorName>
         <givenName>Mirko</givenName>
         <familyName>Reguzzoni</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0002-4027-9347</nameIdentifier>
         <affiliation>International Service for the Geoid (ISG), Politecnico di Milano, Italy</affiliation>
      </contributor>
      <contributor contributorType="DataCurator">
         <contributorName nameType="Personal">Carrion, Daniela</contributorName>
         <givenName>Daniela</givenName>
         <familyName>Carrion</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0003-1262-9394</nameIdentifier>
         <affiliation>International Service for the Geoid (ISG), Politecnico di Milano, Italy</affiliation>
      </contributor>
      <contributor contributorType="DataManager">
         <contributorName nameType="Personal">Rossi, Lorenzo</contributorName>
         <givenName>Lorenzo</givenName>
         <familyName>Rossi</familyName>
         <nameIdentifier nameIdentifierScheme="ORCID">0000-0001-6050-1972</nameIdentifier>
         <affiliation>International Service for the Geoid (ISG), Politecnico di Milano, Italy</affiliation>
      </contributor>
      <contributor contributorType="ContactPerson">
         <contributorName>de Matos, Ana Cristina Oliveira Cancoro</contributorName>
         <affiliation>Centro de Estudos de Geodesia (CENEGEO), São Paulo, Brazil</affiliation>
      </contributor>
      <contributor contributorType="ContactPerson">
         <contributorName>ISG Staff</contributorName>
         <affiliation>International Service for the Geoid (ISG)</affiliation>
      </contributor>
   </contributors>
   <dates>
      <date dateType="Created">2021</date>
   </dates>
   <resourceType resourceTypeGeneral="Dataset">Dataset</resourceType>
   <relatedIdentifiers>
      <relatedIdentifier relatedIdentifierType="URL" relationType="IsDocumentedBy">https://www.isgeoid.polimi.it/Geoid/America/Southamerica/SIRGAS2021_sesion3_martes_geoid2021_Matos.pdf</relatedIdentifier>
      <relatedIdentifier relatedIdentifierType="URL" relationType="References">http://www2.unb.ca/gge/Research/GRL/GeodesyGroup/SHGeo/1_Stokes-Helmert_Technique/1987_Vanicek_et_al.pdf</relatedIdentifier>
      <relatedIdentifier relatedIdentifierType="DOI" relationType="References">10.5194/essd-13-1653-2021</relatedIdentifier>
      <relatedIdentifier relatedIdentifierType="URL" relationType="References">http://www.isgeoid.polimi.it/</relatedIdentifier>
      <relatedIdentifier relatedIdentifierType="DOI" relationType="IsVariantFormOf">10.5880/isg.2021.005</relatedIdentifier>
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   <version>1.0</version>
   <rightsList>
      <rights rightsURI="http://creativecommons.org/licenses/by/4.0/">CC BY 4.0</rights>
   </rightsList>
   <descriptions>
      <description descriptionType="Abstract">The South American gravimetric geoid model, named GEOID2021, was computed thanks to a collaboration of several institutions, companies and universities of South America. The model covers the area between 15°N and 60°S in latitude and 100°W and 30°W in longitude, with a grid resolution of 5' x 5'. It is based on 959,404 terrestrial gravimetric points, the XGM2019 global geopotential model up to degree and order 200 and the SRTMv3 digital terrain model. The short wavelengths of the solution were estimated via Fast Fourier Transform (FFT) with the modified Stokes kernel proposed by Vaníček and Kleusberg (1987). On the other hand, long and medium wavelengths were removed and replaced in the framework of a remove-compute-restore procedure. Regions without gravimetric observations were completed using XGM2019 to its full degree. The calculation of the geoid model was performed by the Canadian package SHGEO (Stokes-Helmert Geoid Software). The comparison between the estimated geoid heights and GPS/levelling data at 4464 points in Argentina, Chile, Colombia, Ecuador and Venezuela (2931, 176, 464, 703 and 190 points, respectively) shows differences with an RMS ranging from 34 cm for Argentina to 92 cm for Ecuador.   <br/>
         <br/>
The geoid model is provided in ISG format 2.0 (ISG Format Specifications), while the file in its original data format is available at the model ISG webpage.   <br/>
      </description>
      <description descriptionType="Other">The International Service for the Geoid (ISG) was founded in 1992 (as International Geoid Service - IGeS) and it is now an official service of the International Association of Geodesy (IAG), under the umbrella of the International Gravity Field Service (IGFS). The main activities of ISG consist in collecting, analysing and redistributing local and regional geoid models, as well as organizing international schools on the geoid determination (Reguzzoni et al., 2021).   <br/>
      </description>
   </descriptions>
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