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<front>
<journal-meta>
<journal-id journal-id-type="publisher">TC</journal-id>
<journal-title-group>
<journal-title>The Cryosphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">TC</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">The Cryosphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1994-0424</issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/tc-7-1971-2013</article-id>
<title-group>
<article-title>Snow thickness retrieval over thick Arctic sea ice using SMOS satellite data</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Maaß</surname>
<given-names>N.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kaleschke</surname>
<given-names>L.</given-names>
<ext-link>https://orcid.org/0000-0001-7086-3299</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Tian-Kunze</surname>
<given-names>X.</given-names>
<ext-link>https://orcid.org/0000-0003-0796-9191</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Drusch</surname>
<given-names>M.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Institute of Oceanography, University of Hamburg, Bundesstraße 53, 20146 Hamburg, Germany</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>European Space Agency, ESA-ESTEC, 2200 AG Noordwijk, the Netherlands</addr-line>
</aff>
<pub-date pub-type="epub">
<day>20</day>
<month>12</month>
<year>2013</year>
</pub-date>
<volume>7</volume>
<issue>6</issue>
<fpage>1971</fpage>
<lpage>1989</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2013 N. Maaß et al.</copyright-statement>
<copyright-year>2013</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/3.0/">https://creativecommons.org/licenses/by/3.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://tc.copernicus.org/articles/7/1971/2013/tc-7-1971-2013.html">This article is available from https://tc.copernicus.org/articles/7/1971/2013/tc-7-1971-2013.html</self-uri>
<self-uri xlink:href="https://tc.copernicus.org/articles/7/1971/2013/tc-7-1971-2013.pdf">The full text article is available as a PDF file from https://tc.copernicus.org/articles/7/1971/2013/tc-7-1971-2013.pdf</self-uri>
<abstract>
<p>The microwave interferometric radiometer of the European Space
  Agency&apos;s Soil Moisture and Ocean Salinity (SMOS) mission measures at
  a frequency of 1.4 GHz in the L-band. In contrast to other
  microwave satellites, low frequency measurements in L-band have
  a large penetration depth in sea ice and thus contain information on
  the ice thickness. Previous ice thickness retrievals have neglected
  a snow layer on top of the ice. Here, we implement a snow layer in
  our emission model and investigate how snow influences L-band
  brightness temperatures and whether it is possible to retrieve snow
  thickness over thick Arctic sea ice from SMOS data.
&lt;br&gt;&lt;br&gt;
  We find that the brightness temperatures above snow-covered sea ice
  are higher than above bare sea ice and that horizontal polarisation
  is more affected by the snow layer than vertical polarisation. In
  accordance with our theoretical investigations, the root mean square
  deviation between simulated and observed horizontally polarised
  brightness temperatures decreases from 20.9 K to
  4.7 K, when we include the snow layer in the
  simulations. Although dry snow is almost transparent in L-band, we
  find brightness temperatures to increase with increasing snow
  thickness under cold Arctic conditions. The brightness temperatures&apos;
  dependence on snow thickness can be explained by the thermal
  insulation of snow and its dependence on the snow layer thickness.
  This temperature effect allows us to retrieve snow thickness over
  thick sea ice. For the best simulation scenario and snow thicknesses
  up to 35 cm, the average snow thickness retrieved from
  horizontally polarised SMOS brightness temperatures agrees within
  0.1 cm with the average snow thickness measured during the
  IceBridge flight campaign in the Arctic in spring 2012. The
  corresponding root mean square deviation is 5.5 cm, and the
  coefficient of determination is &lt;i&gt;r&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt; = 0.58.</p>
</abstract>
<counts><page-count count="19"/></counts>
</article-meta>
</front>
<body/>
<back>
<ref-list>
<title>References</title>
<ref id="ref1">
<label>1</label><mixed-citation publication-type="other" xlink:type="simple">Andersen, S., Tonboe, R., Kaleschke, L., Heygster, G., and Pedersen, L.: Intercomparison of passive microwave sea ice concentration retrievals over the high-concentration Arctic sea ice, J. Geophys. Res, 112, C08004, &lt;a href=&quot;http://dx.doi.org/10.1029/2006JC003543&quot;&gt;https://doi.org/10.1029/2006JC003543&lt;/a&gt;, 2007.</mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple">Bourke, R. and Garrett, R.: Sea ice thickness distribution in the Arctic Ocean, Cold Reg. Sci. Technol., 13, 259–280, 1987.</mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple">Burke, W., Schmugge, T., and Paris, J.: Comparison of 2.8 and 21 cm microwave radiometer observations over soils with emission model calculations, J. Geophys. Res., 84, 287–294, 1979.</mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple">Camps, A., Gourrion, J., Tarongi, J., Gutierrez, A., Barbosa, J., and Castro, R.: RFI analysis in SMOS imagery, in: Proceedings IGARSS, 2007–2010, 2010.</mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple">Comiso, J., Cavalieri, D., and Markus, T.: Sea ice concentration, ice temperature, and snow depth using AMSR-E data, IEEE T. Geosci. Remote, 41, 243–252, 2003.</mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple">Cox, G. and Weeks, W.: Salinity variations in sea ice, J. Glaciol., 13, 109–120, 1974.</mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple">Cox, G. and Weeks, W.: Equations for determining the gas and brine volumes in sea ice samples, J. Glaciol., 29, 306–316, 1983.</mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple">Doronin, Y.: Thermal interaction of the atmosphere and the hydrosphere in the Arctic, CoronetBooks, Philadelphia, 1971.</mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple">Eicken, H.: Salinity profiles of Antarctic sea ice: Field data and model results, J. Geophys. Res., 97, 15545–15557, 1992.</mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple">Farrell, S., Kurtz, N., Connor, L., Elder, B., Leuschen, C., Markus, T., McAdoo, D., Panzer, B., Richter-Menge, J., and Sonntag, J.: A first assessment of IceBridge snow and ice thickness data over Arctic sea ice, IEEE T. Geosci. Remote, 50, 2098–2111, 2012.</mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple">Giles, K., Laxon, S., Wingham, D., Wallis, D., Krabill, W., Leuschen, C., McAdoo, D., Manizade, S., and Raney, R.: Combined airborne laser and radar altimeter measurements over the Fram Strait in May 2002, Remote Sens. Environ., 111, 182–194, 2007.</mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple">Hall, D.: Remote sensing applications to hydrology: imaging radar, Hydrolog. Sci. J., 41, 609–624, 1996.</mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple">Hall, D., Key, J., Casey, K., Riggs, G., and Cavalieri, D.: Sea ice surface temperature product from MODIS, IEEE T. Geosci. Remote, 42, 1076–1087, 2004.</mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple">Hallikainen, M.: Microwave radiometry of snow, Adv. Space Res., 9, 267–275, 1989.</mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple">Kaleschke, L., Lüpkes, C., Vihma, T., Haarpaintner, J., Bochert, A., Hartmann, J., and Heygster, G.: SSM/I sea ice remote sensing for mesoscale ocean-atmosphere interaction analysis, Can. J. Remote Sens., 27, 526–537, 2001.</mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple">Kaleschke, L., Maaß, N., Haas, C., Hendricks, S., Heygster, G., and Tonboe, R. T.: A sea-ice thickness retrieval model for 1.4 GHz radiometry and application to airborne measurements over low salinity sea-ice, The Cryosphere, 4, 583–592, &lt;a href=&quot;http://dx.doi.org/10.5194/tc-4-583-2010&quot;&gt;https://doi.org/10.5194/tc-4-583-2010&lt;/a&gt;, 2010.</mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple">Kaleschke, L., Tian-Kunze, X., Maaß, N., Mäkynen, M., and Drusch, M.: Sea ice thickness retrieval from SMOS brightness temperatures during the Arctic freeze-up period, Geophys. Res. Lett., 39, L05501, &lt;a href=&quot;http://dx.doi.org/10.1029/2012GL050916&quot;&gt;https://doi.org/10.1029/2012GL050916&lt;/a&gt;, 2012.</mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple">Kerr, Y., Waldteufel, P., Wigneron, J., Martinuzzi, J., Font, J., and Berger, M.: Soil moisture retrieval from space: the Soil Moisture and Ocean Salinity (SMOS) mission, IEEE T. Geosci. Remote, 39, 1729–1735, 2001.</mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple">Klein, L. and Swift, C.: An improved model for the dielectric constant of sea water at microwave frequencies, IEEE T. Antenn. Propag., 25, 104–111, 1977.</mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple">Krabill, W. B.: IceBridge KT19 IR Surface Temperature, online, NASA DAAC at NSIDC, Boulder, Colorado, USA, 2012.</mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple">Kurtz, N.: IceBridge Quick Look Sea Ice Freeboard, Snow Depth, and Thickness Product Manual, 2012.</mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple">Kurtz, N. and Farrell, S.: Large-scale surveys of snow depth on Arctic sea ice from operation IceBridge, Geophys. Res. Lett., 38, L20505, &lt;a href=&quot;http://dx.doi.org/10.1029/2011GL049216&quot;&gt;https://doi.org/10.1029/2011GL049216&lt;/a&gt;, 2011.</mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple">Kurtz, N., Studinger, M., Harbeck, J., Onana, V., and Farrell, S.: IceBridge Sea Ice Freeboard, Snow Depth, and Thickness, online, NASA DAAC at NSIDC, Boulder, Colorado USA, 2012.</mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple">Kurtz, N., Farrell, S., Studinger, M., Galin, N., Harbeck, J., Lindsay, R., Onana, V., Panzer, B., and Sonntag, J.: Sea ice thickness, freeboard, and snow depth products from Operation IceBridge airborne data, The Cryosphere, 7, 1035–1056, &lt;a href=&quot;http://dx.doi.org/10.5194/tc-7-1035-2013&quot;&gt;https://doi.org/10.5194/tc-7-1035-2013&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple">Kwok, R. and Cunningham, G.: ICESat over Arctic sea ice: estimation of snow depth and ice thickness, J. Geophys. Res., 113, C08010, &lt;a href=&quot;http://dx.doi.org/10.1029/2008JC004753&quot;&gt;https://doi.org/10.1029/2008JC004753&lt;/a&gt;, 2008.</mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple">Kwok, R., Panzer, B., Leuschen, C., Pang, S., Markus, T., Holt, B., and Gogineni, S.: Airborne surveys of snow depth over Arctic sea ice, J. Geophys. Res., 116, C11018, &lt;a href=&quot;http://dx.doi.org/10.1029/2011JC007371&quot;&gt;https://doi.org/10.1029/2011JC007371&lt;/a&gt;, 2011.</mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple">Maaß, N.: Remote sensing of sea ice thickness using SMOS data, Reports on Earth System Science, 131, available at: &lt;a href=&quot;www.mpimet.mpg.de/fileadmin/publikationen/Reports/WEB_BzE_131.pdf&quot;&gt;www.mpimet.mpg.de/fileadmin/publikationen/Reports/WEB_BzE_131.pdf&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple">Markus, T. and Cavalieri, D. J.: Snow depth distribution over sea ice in the Southern Ocean from satellite passive microwave data, Antarct. Res. Ser., 74, 19–39, 1998.</mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple">Massom, R., Drinkwater, M., and Haas, C.: Winter snow cover on sea ice in the Weddell Sea, J. Geophys. Res., 102, 1101–1117, 1997.</mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple">Maykut, G. and Untersteiner, N.: Some results from a time-dependent thermodynamic model of sea ice, J. Geophys. Res., 76, 1550–1575, 1971.</mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple">Menashi, J., Germain, K., Swift, C., Comiso, J., and Lohanick, A.: Low-frequency passive-microwave observations of sea ice in the Weddell Sea, J. Geophys. Res., 98, 22569–22577, 1993.</mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple">Misra, S. and Ruf, C.: Analysis of radio frequency interference detection algorithms in the angular domain for SMOS, IEEE T. Geosci. Remote, 50, 1448–1457, 2012.</mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple">Oliva, R., Daganzo, E., Kerr, Y., Mecklenburg, S., Nieto, S., Richaume, P., and Gruhier, C.: SMOS radio frequency interference scenario: status and actions taken to improve the RFI environment in the 1400–1427-MHz passive band, IEEE T. Geosci. Remote, 50, 1427–1439, 2012.</mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple">Pinori, S., Crapolicchio, R., and Mecklenburg, S.: Preparing the ESA-SMOS (soil moisture and ocean salinity) mission-overview of the user data products and data distribution strategy, in: Microwave Radiometry and Remote Sensing of the Environment, MICRORAD, IEEE, 1–4, 2008.</mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple">Pounder, E.: The Physics of Ice, Pergamon Press, the Commonwealth and International Library, Geophysics Division, Oxford, 1965.</mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple">Rothrock, D., Yu, Y., and Maykut, G.: Thinning of the Arctic sea-ice cover, Geophys. Res. Lett., 26, 3469–3472, 1999.</mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple">Rott, H. and Mätzler, C.: Possibilities and limits of synthetic aperture radar for snow and glacier surveying, Ann. Glaciol., 9, 195–199, 1987.</mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple">Spreen, G., Kaleschke, L., and Heygster, G.: Sea ice remote sensing using AMSR-E 89 &lt;abbr&gt;GHz&lt;/abbr&gt; channels, J. Geophys. Res., 113, C02S03, &lt;a href=&quot;http://dx.doi.org/10.1029/2005JC003384&quot;&gt;https://doi.org/10.1029/2005JC003384&lt;/a&gt;, 2008.</mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple">Stroeve, J. C., Markus, T., Maslanik, J. A., Cavalieri, D. J., Gasiewski, A. J., Heinrichs, J. F., Holmgren, J., Perovich, D. K., and Sturm, M.: Impact of surface roughness on AMSR-E sea ice products, IEEE T. Geosci. Remote, 44, 3103–3117, 2006.</mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple">Tiuri, M., Sihvola, A., Nyfors, E., and Hallikainen, M.: The complex dielectric constant of snow at microwave frequencies, IEEE J. Oceanic Eng., 9, 377–382, 1984.</mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple">Tonboe, R.: Simulations of the snow covered sea ice surface temperature and microwave effective temperature at L-Band, in: ESA Support To Science Element (STSE) Final Report, edited by: Kaleschke, L., ESA ESTEC Contract No.: 4000101476/10/NL/CT, 380 pp., Univ. Hamburg, Institute of Oceanography, available at: &lt;a href=&quot;https://icdc.zmaw.de/fileadmin/user_upload/icdc_Dokumente/SMOSICE_FinalReport_2013.pdf&quot;&gt;https://icdc.zmaw.de/fileadmin/user_upload/icdc_Dokumente/SMOSICE_FinalReport_2013.pdf&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple">Ulaby, F., Moore, R., and Fung, A.: Microwave Remote Sensing: Active and Passive, vol. 1 – Microwave Remote Sensing Fundamentals and Radiometry, Addison-Wesley, London, UK, 1981.</mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple">Untersteiner, N.: Calculations of temperature regime and heat budget of sea ice in the Central Arctic, J. Geophys. Res., 69, 4755–4766, 1964.</mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple">Vant, M., Ramseier, R., and Makios, V.: The complex-dielectric constant of sea ice at frequencies in the range 0.1–40 &lt;abbr&gt;GHz&lt;/abbr&gt;, J. Appl. Phys., 49, 1264–1280, 1978.</mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple">Warren, S., Rigor, I., Untersteiner, N., Radionov, V., Bryazgin, N., Aleksandrov, Y., and Colony, R.: Snow depth on Arctic sea ice, J. Climate, 12, 1814–1829, 1999.</mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple">Yu, Y. and Rothrock, D.: Thin ice thickness from satellite thermal imagery, J. Geophys. Res., 101, 25753–25766, 1996.</mixed-citation>
</ref>
<ref id="ref47">
<label>47</label><mixed-citation publication-type="other" xlink:type="simple">Zine, S., Boutin, J., Font, J., Reul, N., Waldteufel, P., Gabarró, C., Tenerelli, J., Petitcolin, F., Vergely, J., Talone, M., and Delwart, S.: Overview of the SMOS sea surface salinity prototype processor, IEEE T. Geosci. Remote, 46, 621–645, 2008.</mixed-citation>
</ref>
</ref-list>
</back>
</article>