December 9, 2025 Dataset Open Access

Sadikni, Remon; Kern, Stefan

DataCite XML Export

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  <identifier identifierType="DOI">10.25592/uhhfdm.18070</identifier>
  <creators>
    <creator>
      <creatorName>Sadikni, Remon</creatorName>
      <affiliation>Integrated Climate Data Center (ICDC), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany</affiliation>
    </creator>
    <creator>
      <creatorName>Kern, Stefan</creatorName>
      <nameIdentifier nameIdentifierScheme="ORCID" schemeURI="http://orcid.org/">0000-0001-7281-3746</nameIdentifier>
      <affiliation>Integrated Climate Data Center (ICDC), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany</affiliation>
    </creator>
  </creators>
  <titles>
    <title>Daily melt-pond fraction on Arctic sea ice from TERRA MODIS visible imagery</title>
  </titles>
  <publisher>Universität Hamburg</publisher>
  <publicationYear>2025</publicationYear>
  <subjects>
    <subject>sea ice</subject>
    <subject>melt ponds</subject>
    <subject>Arctic</subject>
    <subject>surface type fraction</subject>
    <subject>summer melt</subject>
    <subject>satellite remote sensing</subject>
    <subject>mixed pixel approach</subject>
    <subject>artificial neural network</subject>
    <subject>MODIS</subject>
    <subject>ICDC</subject>
  </subjects>
  <dates>
    <date dateType="Issued">2025-12-09</date>
  </dates>
  <language>en</language>
  <resourceType resourceTypeGeneral="Dataset"/>
  <alternateIdentifiers>
    <alternateIdentifier alternateIdentifierType="url">https://www.fdr.uni-hamburg.de/record/18070</alternateIdentifier>
  </alternateIdentifiers>
  <relatedIdentifiers>
    <relatedIdentifier relatedIdentifierType="DOI" relationType="Cites">10.5194/tc‐6‐431‐2012</relatedIdentifier>
    <relatedIdentifier relatedIdentifierType="DOI" relationType="IsNewVersionOf">10.1594/WDCC/MODIS__Arctic__MPF_V02</relatedIdentifier>
    <relatedIdentifier relatedIdentifierType="DOI" relationType="IsPartOf">10.25592/uhhfdm.18069</relatedIdentifier>
  </relatedIdentifiers>
  <version>2025_fv0.01</version>
  <rightsList>
    <rights rightsURI="https://creativecommons.org/licenses/by/4.0/legalcode">Creative Commons Attribution 4.0 International</rights>
    <rights rightsURI="info:eu-repo/semantics/openAccess">Open Access</rights>
  </rightsList>
  <descriptions>
    <description descriptionType="Abstract">&lt;p&gt;&lt;strong&gt;Abstract:&lt;/strong&gt;&amp;nbsp;Reflectance measurements carried out at Terra MODIS bands 1, 3 and 4 are combined in a spectral un-mixing approach to estimate the melt-pond fraction on Arctic sea ice north of 60&amp;deg;N for months June through August for the years 2000 through 2024. The resulting data set has daily temporal sampling and is offered on a polar-stereographic grid (true latitude is 70&amp;deg;N) with 500 m x 500 m and 12.5 km x 12.5 km grid resolution. The data files contain, in addition to the melt-pond fraction, also the fraction of open water between the sea ice and the net sea-ice surface fraction, i.e. the fraction of sea ice without melt ponds. For information about the approach used and the validation of the data set offered here we refer to &lt;a href="https://doi.org/10.5194/tc‐6‐431‐2012"&gt;R&amp;ouml;sel et al. (2012)&lt;/a&gt; and Sadikni and Kern (2025).&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;TableOfContents:&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
	&lt;li&gt;500 m x 500 m product: grid-cell fraction of melt ponds (on sea ice); grid-cell fraction of sea ice without melt ponds; grid-cell fraction of open water&lt;/li&gt;
	&lt;li&gt;12.5 km x 12.5 km product: grid-cell fraction of melt ponds (on sea ice); grid-cell fraction of sea ice without melt ponds; grid-cell fraction of open water; grid-cell_fraction_of_melt_ponds standard_deviation; grid-cell_fraction_of_sea_ice_without_melt_ponds standard_deviation; grid-cell_fraction_of_open_water standard_deviation; number of clear-sky 500 m grid cells; clear-sky mask&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;While the 12.5 km x 12.5 km comes with latitude and longitude values for each grid cell, those of the 500 m x 500 m product are provided in a separate netCDF file.&lt;/p&gt;

&lt;p&gt;Note that the grid resolution of 12.5 km (and 500m) is only valid at the latitude at which the tangential plane of the polar stereographic projection touches the Earth&amp;#39;s surface - here 70&amp;deg;N. North of this latitude the actual grid cell area is smaller, south of it it is larger (see also&amp;nbsp;&lt;a href="https://nsidc.org/data/user-resources/help-center/guide-nsidcs-polar-stereographic-projection#anchor-grid-distortion"&gt;https://nsidc.org/data/user-resources/help-center/guide-nsidcs-polar-stereographic-projection#anchor-grid-distortion&lt;/a&gt;). In order to assist in the computation of the actual area (in km2) covered by melt ponds (or the other two surface types) we provide a netCDF file of the true area of each grid cell of the 12.5 km x 12.5 km product.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Technical Info:&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
	&lt;li&gt;500 m x 500 m product: dimensions: 13286 columns x 13293 rows; temporalExtent_startDate: 2000-06-01; temporalExtent_endDate: 2024-08-31; temporalResolution: daily; spatialResolution: 500; spatialResolutionUnit: meter; horizontalResolutionXdirection: 500; horizontalResolutionXdirectionUnit: meter; horizontalResolutionYdirection: 500; horizontalResolutionYdirectionUnit: meter; verticalResolution: none; verticalResolutionUnit: none; verticalStart: none; verticalEnd: none; instrumentName: Moderate Resolution Spectroradiometer (MODIS); instrumentType: 32-band imaging spectroradiometer; instrumentLocation: Earth Observation Satellite (EOS) Terra; instrumentProvider: NOAA/NASA&lt;/li&gt;
	&lt;li&gt;12.5 km x 12.5 km product:&amp;nbsp;dimensions: 531 columns x 531 rows; temporalExtent_startDate: 2000-06-01; temporalExtent_endDate: 2024-08-31; temporalResolution: daily; spatialResolution: 12500; spatialResolutionUnit: meter; horizontalResolutionXdirection: 12500; horizontalResolutionXdirectionUnit: meter; horizontalResolutionYdirection: 12500; horizontalResolutionYdirectionUnit: meter; verticalResolution: none; verticalResolutionUnit: none; verticalStart: none; verticalEnd: none; instrumentName: Moderate Resolution Spectroradiometer (MODIS); instrumentType: 32-band imaging spectroradiometer; instrumentLocation: Earth Observation Satellite (EOS) Terra; instrumentProvider: NOAA/NASA&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Missing data (either because the MOD09GA product has gaps or because the melt-pond fraction retrieval failed): 2000-08-06 to 2000-08-17; 2001-06-16 to 2001-07-02; 2002-06-15 to 2002-06-19; 2002-07-11; 2004-06-20 to 2004-06-22; 2005-07-21; 2008-08-06 to 2008-08-08; 2008-08-11; 2008-08-22; 2010-06-17; 2010-08-01; 2010-08-16; 2013-06-09; 2013-06-15; 2014-08-02; 2016-06-07; 2016-06-08; 2016-06-11; 2016-08-12; 2018-08-04; 2021-08-11; 2024-06-21; 2024-06-22; 2024-06-25.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; For a description of the methods used see Sadikni and Kern, 2025.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Units:&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
	&lt;li&gt;500 m x 500 m product: 1, 1, 1&lt;/li&gt;
	&lt;li&gt;12500 m x 12500 m product: 1, 1, 1, 1, 1, 1, 1, 1&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;geoLocations:&lt;/strong&gt; westBoundLongitude: -180.0 degrees East; eastBoundLongitude: 180.0 degrees East; southBoundLatitude: 60.0 degrees North; northBoundLatitude: 90.0 degrees North; geoLocationPlace: northern hemisphere&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Size:&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
	&lt;li&gt;500 m x 500 m product: Single file: 2.1 GigaByte; zip-file or one month: 1.5 to 4.0 GigaByte (depends on gaps due to cloud cover); total volume (as unpacked netCDF): 4.87 TeraByte&amp;nbsp;&lt;/li&gt;
	&lt;li&gt;12.5 km x 12.5 km product: Single file: ~10 MegaByte; zip-file of one month: 60 to 100 MegaByte (depends on gaps due to cloud cover);&amp;nbsp; total volume (as unpacked netCDF): 22.8 GigaByte&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Format:&lt;/strong&gt; netCDF&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;DataSources:&amp;nbsp;&lt;/strong&gt;MODerate resolution Imaging Spectroradiometer MODIS aboard the Earth Observation Satellite (EOS) Terra collection 6.1 product MOD09A1 of the surface spectral reflectance:&amp;nbsp;&lt;a href="https://lpdaac.usgs.gov/products/mod09gav061/"&gt;https://lpdaac.usgs.gov/products/mod09gav061/&lt;/a&gt; (last access: Dec. 6, 2024).&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Contact:&lt;/strong&gt;&amp;nbsp;&lt;a href="mailto:remon.sadikni@uni-hamburg.de"&gt;remon.sadikni (at) uni-hamburg.de&lt;/a&gt;;&amp;nbsp;&lt;a href="mailto:stefan.kern@uni-hamburg.de"&gt;stefan.kern (at) uni-hamburg.de&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Web page:&lt;/strong&gt; &lt;a href="https://www.cen.uni-hamburg.de/en/icdc/data/cryosphere/arctic-meltponds.html"&gt;https://www.cen.uni-hamburg.de/en/icdc/data/cryosphere/arctic-meltponds.html&lt;/a&gt;&lt;/p&gt;</description>
  </descriptions>
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