<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.3 20210610//EN" "JATS-journalpublishing1-3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="1.3" xml:lang="en">
  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher-id">Ecological Safety of Coastal and Shelf Zones of Sea</journal-id>
      <journal-title-group>
        <journal-title>Ecological Safety of Coastal and Shelf Zones of Sea</journal-title>
      </journal-title-group>
      <issn publication-format="print">2413-5577</issn>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id">20250103</article-id>

      <article-categories>
        <subj-group subj-group-type="article-type">
          <subject>Research Article</subject>
        </subj-group>
      </article-categories>

      <title-group>
        <article-title>The Danube River Water Discharge According to Satellite Optical Data of the Landsat Series</article-title>
      </title-group>

      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Suslin</surname>
            <given-names>V. V.</given-names>
          </name>
          <address>
            <country country="RU">Russian Federation</country>
          </address>
          <email>slava.suslin@mhi-ras.ru</email>
          <xref ref-type="aff" rid="aff1"/>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Sholar</surname>
            <given-names>S. A.</given-names>
          </name>
          <address>
            <country country="RU">Russian Federation</country>
          </address>
          <email>sa.sholar@mail.ru</email>
          <xref ref-type="aff" rid="aff1"/>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Podgibailov</surname>
            <given-names>E. A.</given-names>
          </name>
          <address>
            <country country="RU">Russian Federation</country>
          </address>
          <email>e.podgibailov@yandex.ru</email>
          <xref ref-type="aff" rid="aff1"/>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Martynov</surname>
            <given-names>O. V.</given-names>
          </name>
          <address>
            <country country="RU">Russian Federation</country>
          </address>
          <email>oleg.martynov.49@mail.ru</email>
          <xref ref-type="aff" rid="aff1"/>
        </contrib>
      </contrib-group>

      <aff id="aff1">
        <institution>Marine Hydrophysical Institute of RAS</institution>
        <addr-line>Sevastopol</addr-line>
        <country country="RU">Russia</country>
      </aff>

      <pub-date date-type="pub" iso-8601-date="2025-03-31" publication-format="electronic">
        <day>31</day>
        <month>03</month>
        <year>2025</year>
      </pub-date>
      <volume>2025</volume>
      <issue>1</issue>
      <fpage>42</fpage>
      <lpage>50</lpage>

      <history>
        <date date-type="received" iso-8601-date="2024-07-08">
          <day>08</day>
          <month>07</month>
          <year>2024</year>
        </date>
        <date date-type="rev-recd" iso-8601-date="2024-12-17">
          <day>17</day>
          <month>12</month>
          <year>2024</year>
        </date>
        <date date-type="accepted" iso-8601-date="2024-09-30">
          <day>30</day>
          <month>09</month>
          <year>2024</year>
        </date>
      </history>

      <permissions>
        <copyright-statement>Copyright © 2025, V. V. Suslin, S. A. Sholar, E. A. Podgibailov, O. V. Martynov</copyright-statement>
        <copyright-year>2025</copyright-year>
        <copyright-holder>V. V. Suslin, S. A. Sholar, E. A. Podgibailov, O. V. Martynov</copyright-holder>
        <ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/>
        <license>
          <ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by-nc/4.0/</ali:license_ref>
        </license>
      </permissions>
      <self-uri xlink:href="https://ecological-safety.ru/en/repository/issues/2025/01/03/" xlink:title="Page of article">https://ecological-safety.ru/en/repository/issues/2025/01/03/</self-uri>

      <abstract>
        <p>The paper aims to find the correlation relationship between the land–water area ratio for a fixed area of the Danube Delta and the total river discharge using Landsat series satellite products and SMHI Hypeweb hydrological model. The study period covered 1984–2010. We used a total of 132 satellite images in one band in the near-infrared spectral range with a spatial resolution of 30 m. Two study areas were selected: the delta area with channel and land (44.9–45.4°N, 29.55–29.60°E) and the control area of the mouth seashore (44.9–45.4°N and 29.80–29.85°E). For each of them a histogram was plotted which characterised the reflected light in relative units and their corresponding numbers of pixels. The signal from the first area was found to be in the range of 7000–26,000 r.u., whereas from the second one it was 7000–8000 r.u. This distinction allowed us to separate the delta areas occupied by river water from those of land. For this purpose, we calculated the ratio between the number of pixels corresponding to a value of 7000–8000 r.u. to all pixels in the area. Then we found the correlation between the river discharge from the SMHI Hypeweb hydrological model and the proportion of pixels corresponding to areas occupied by water. The regression y = 7.78·10⁻⁴·x⁰·⁰⁹ – 5.98·10⁻⁴ was obtained. The analysis of seasonal variability showed that in the studied delta area, the share of pixels related to water-occupied areas > 0.5 corresponds to the months from March to May, and the minimum values &lt; 0.3 correspond to July–September. All this is consistent with the period of intensity of precipitation and snowmelt in the Danube River basin area. The data from this work may be useful to researchers assessing the impact of this river discharge on the hydrological regime and condition of the Black Sea.</p>
      </abstract>

      <kwd-group>
        <kwd>remote sensing</kwd>
        <kwd>Danube River</kwd>
        <kwd>river discharge</kwd>
        <kwd>Landsat TM</kwd>
        <kwd>SMHI Hypeweb</kwd>
        <kwd>hydrological model</kwd>
        <kwd>Black Sea</kwd>
      </kwd-group>

      <funding-group>
        <funding-statement>The work was carried out under state assignment of MHI RAS FNNN-2024-0012 "Analysis, diagnosis and operational forecast of the state of hydrophysical and hydrochemical fields of marine areas based on mathematical modeling using data from remote and contact measurement methods".</funding-statement>
      </funding-group>

      <author-notes>
        <p><bold>About the authors:</bold></p>
        <p><bold>Vyacheslav V. Suslin</bold>, Head of Department of the Oceanic Processes Dynamics, Leading Research Associate, Marine Hydrophysical Institute of RAS (2 Kapitanskaya Str., 299011, Sevastopol, Russia), PhD (Phys.-Math.), ORCID ID: 0000-0002-8627-7603, Scopus Author ID: 6603566261, ResearcherID: B-4994-2017, <email>slava.suslin@mhi-ras.ru</email></p>
        <p><bold>Stanislav A. Sholar</bold>, Research Associate, Marine Hydrophysical Institute of RAS (2 Kapitanskaya Str., 299011, Sevastopol, Russia), PhD (Tech.), ORCID ID: 0000-0002-7242-3403, Scopus Author ID: 57189886286, ResearcherID: GSD-9744-2022, <email>sa.sholar@mail.ru</email></p>
        <p><bold>Evgeny A. Podgibailov</bold>, Leading Engineer, Marine Hydrophysical Institute of RAS (2 Kapitanskaya Str., 299011, Sevastopol, Russia), ORCID ID: 0009-0002-2570-1367, Scopus Author ID: 58687010100, ResearcherID: KHZ-5622-2024, <email>e.podgibailov@yandex.ru</email></p>
        <p><bold>Oleg V. Martynov</bold>, Senior Research Associate, Marine Hydrophysical Institute of RAS (2 Kapitanskaya Str., 299011, Sevastopol, Russia), PhD (Tech.), Scopus Author ID: 57201603369, <email>oleg.martynov.49@mail.ru</email></p>
        <p><bold>Contribution of the authors:</bold></p>
        <p><bold>Vyacheslav V. Suslin</bold> – problem statement, concept development, results analysis, manuscript writing</p>
        <p><bold>Stanislav A. Sholar</bold> – graphical material construction, literature review on the study problem, discussion of results, formulation of conclusions</p>
        <p><bold>Evgeny A. Podgibailov</bold> – collection of study materials, primary processing and sorting of data, discussion of the results, article execution</p>
        <p><bold>Oleg V. Martynov</bold> – literature review on the study problem, discussion of the results, article execution</p>
        <p><italic>All the authors have read and approved the final manuscript.</italic></p>
      </author-notes>
    </article-meta>
  </front>

  <body>
    <p>Article text not included.</p>
  </body>

  <back>
    <ref-list>
      <title>REFERENCES</title>
      <ref id="B1">
        <label>1.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Tsyganova</surname><given-names>M.V.</given-names></name>
            <name><surname>Lemeshko</surname><given-names>E.M.</given-names></name>
            <name><surname>Ryabtsev</surname><given-names>Yu.N.</given-names></name>
          </person-group>
          <article-title>Influence of Upwelling on River Plume Development in the Coastal Zone of the North-Western Black Sea Shelf Based on Numerical Modelling</article-title>
          <source>Ecological Safety of Coastal and Shelf Zones of Sea</source>
          <year>2023</year>
          <issue>1</issue>
          <fpage>20</fpage>
          <lpage>30</lpage>
        </element-citation>
      </ref>
      <ref id="B2">
        <label>2.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Kondratev</surname><given-names>S.I.</given-names></name>
          </person-group>
          <article-title>Three Typical Hydrological-Hydrochemical Situations near the Danube River Mouth Based on the Marine Hydrophysical Institute Research Expeditions in 1997-2013</article-title>
          <source>Physical Oceanography</source>
          <year>2019</year>
          <volume>26</volume>
          <issue>4</issue>
          <fpage>326</fpage>
          <lpage>340</lpage>
          <pub-id pub-id-type="doi">10.22449/1573-160X-2019-4-326-340</pub-id>
        </element-citation>
      </ref>
      <ref id="B3">
        <label>3.</label>
        <element-citation publication-type="book">
          <person-group person-group-type="author">
            <name><surname>Goryachkin</surname><given-names>Yu.N.</given-names></name>
            <name><surname>Ivanov</surname><given-names>V.A.</given-names></name>
          </person-group>
          <source>Black Sea Level: Past, Present and Future</source>
          <publisher-loc>Sevastopol</publisher-loc>
          <publisher-name>MHI NAS of Ukraine</publisher-name>
          <year>2006</year>
          <size units="pages">210</size>
          <comment>(in Russian)</comment>
        </element-citation>
      </ref>
      <ref id="B4">
        <label>4.</label>
        <element-citation publication-type="paper-conference">
          <person-group person-group-type="author">
            <name><surname>Terekhov</surname><given-names>A.G.</given-names></name>
            <name><surname>Dolgikh</surname><given-names>S.A.</given-names></name>
            <name><surname>Pak</surname><given-names>I.T.</given-names></name>
            <name><surname>Makarenko</surname><given-names>N.G.</given-names></name>
          </person-group>
          <article-title>Satellite-Based Diagnostics of Water Discharge in Snow-Ice Fed Rivers Using the Kash River as an Example (PRC)</article-title>
          <source>Proceedings of the 13th All-Russian Open Conference "Current Problems of Remote Sensing of Earth from Space"</source>
          <year>2015</year>
          <fpage>140</fpage>
          <comment>(in Russian)</comment>
        </element-citation>
      </ref>
      <ref id="B5">
        <label>5.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Mukhamedjanov</surname><given-names>I.D.</given-names></name>
            <name><surname>Konstantinova</surname><given-names>A.M.</given-names></name>
            <name><surname>Loupian</surname><given-names>E.A.</given-names></name>
            <name><surname>Umirzakov</surname><given-names>G.U.</given-names></name>
          </person-group>
          <article-title>Evaluation of Satellite Monitoring Capabilities of Stream Runoff Based on the Amu Darya River State Analysis</article-title>
          <source>Sovremennye Problemy Distantsionnogo Zondirovaniya Zemli iz Kosmosa</source>
          <year>2022</year>
          <volume>19</volume>
          <issue>1</issue>
          <fpage>87</fpage>
          <lpage>103</lpage>
          <pub-id pub-id-type="doi">10.21046/2070-7401-2022-19-1-87-103</pub-id>
          <comment>(in Russian)</comment>
        </element-citation>
      </ref>
      <ref id="B6">
        <label>6.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Gleason</surname><given-names>C.J.</given-names></name>
            <name><surname>Durand</surname><given-names>M.T.</given-names></name>
          </person-group>
          <article-title>Remote Sensing of River Discharge: A Review and a Framing for the Discipline</article-title>
          <source>Remote Sensing</source>
          <year>2020</year>
          <volume>12</volume>
          <issue>7</issue>
          <fpage>1107</fpage>
          <pub-id pub-id-type="doi">10.3390/rs12071107</pub-id>
        </element-citation>
      </ref>
      <ref id="B7">
        <label>7.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Bjerklie</surname><given-names>D.M.</given-names></name>
            <name><surname>Birkett</surname><given-names>C.M.</given-names></name>
            <name><surname>Jones</surname><given-names>J.W.</given-names></name>
            <name><surname>Carabajal</surname><given-names>C.</given-names></name>
            <name><surname>Rover</surname><given-names>J.A.</given-names></name>
            <name><surname>Fulton</surname><given-names>J.W.</given-names></name>
            <name><surname>Garambois</surname><given-names>P.-A.</given-names></name>
          </person-group>
          <article-title>Satellite Remote Sensing Estimation of River Discharge: Application to the Yukon River Alaska</article-title>
          <source>Journal of Hydrology</source>
          <year>2018</year>
          <volume>561</volume>
          <fpage>1000</fpage>
          <lpage>1018</lpage>
          <pub-id pub-id-type="doi">10.1016/j.jhydrol.2018.04.005</pub-id>
        </element-citation>
      </ref>
      <ref id="B8">
        <label>8.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Bjerklie</surname><given-names>D.M.</given-names></name>
            <name><surname>Dingman</surname><given-names>S.L.</given-names></name>
            <name><surname>Vorosmarty</surname><given-names>C.J.</given-names></name>
            <name><surname>Bolster</surname><given-names>C.H.</given-names></name>
            <name><surname>Congalton</surname><given-names>R.G.</given-names></name>
          </person-group>
          <article-title>Evaluating the Potential for Measuring River Discharge from Space</article-title>
          <source>Journal of Hydrology</source>
          <year>2003</year>
          <volume>278</volume>
          <issue>1-4</issue>
          <fpage>17</fpage>
          <lpage>38</lpage>
          <pub-id pub-id-type="doi">10.1016/S0022-1694(03)00129-X</pub-id>
        </element-citation>
      </ref>
      <ref id="B9">
        <label>9.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Sichangi</surname><given-names>A.W.</given-names></name>
            <name><surname>Wang</surname><given-names>L.</given-names></name>
            <name><surname>Yang</surname><given-names>K.</given-names></name>
            <name><surname>Chen</surname><given-names>D.</given-names></name>
            <name><surname>Wang</surname><given-names>Z.</given-names></name>
            <name><surname>Li</surname><given-names>X.</given-names></name>
            <name><surname>Zhou</surname><given-names>J.</given-names></name>
            <name><surname>Liu</surname><given-names>W.</given-names></name>
            <name><surname>Kuria</surname><given-names>D.</given-names></name>
          </person-group>
          <article-title>Estimating Continental River Basin Discharges Using Multiple Remote Sensing Datasets</article-title>
          <source>Remote Sensing of Environment</source>
          <year>2016</year>
          <volume>179</volume>
          <fpage>36</fpage>
          <lpage>53</lpage>
          <pub-id pub-id-type="doi">10.1016/j.rse.2016.03.019</pub-id>
        </element-citation>
      </ref>
      <ref id="B10">
        <label>10.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Filippucci</surname><given-names>P.</given-names></name>
            <name><surname>Brocca</surname><given-names>L.</given-names></name>
            <name><surname>Bonafoni</surname><given-names>S.</given-names></name>
            <name><surname>Saltalippi</surname><given-names>C.</given-names></name>
            <name><surname>Wagner</surname><given-names>W.</given-names></name>
            <name><surname>Tarpanelli</surname><given-names>A.</given-names></name>
          </person-group>
          <article-title>Sentinel-2 High-Resolution Data for River Discharge Monitoring</article-title>
          <source>Remote Sensing of Environment</source>
          <year>2022</year>
          <volume>281</volume>
          <fpage>113255</fpage>
          <pub-id pub-id-type="doi">10.1016/j.rse.2022.113255</pub-id>
        </element-citation>
      </ref>
      <ref id="B11">
        <label>11.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Mukhamediev</surname><given-names>R.I.</given-names></name>
            <name><surname>Terekhov</surname><given-names>A.</given-names></name>
            <name><surname>Sagatdinova</surname><given-names>G.</given-names></name>
            <name><surname>Amirgaliyev</surname><given-names>Y.</given-names></name>
            <name><surname>Gopejenko</surname><given-names>V.</given-names></name>
            <name><surname>Abayev</surname><given-names>N.</given-names></name>
            <name><surname>Kuchin</surname><given-names>Y.</given-names></name>
            <name><surname>Popova</surname><given-names>Y.</given-names></name>
            <name><surname>Symagulov</surname><given-names>A.</given-names></name>
          </person-group>
          <article-title>Estimation of the Water Level in the Ili River from Sentinel-2 Optical Data Using Ensemble Machine Learning</article-title>
          <source>Remote Sensing</source>
          <year>2023</year>
          <volume>15</volume>
          <issue>23</issue>
          <fpage>5544</fpage>
          <pub-id pub-id-type="doi">10.3390/rs15235544</pub-id>
        </element-citation>
      </ref>
      <ref id="B12">
        <label>12.</label>
        <element-citation publication-type="paper-conference">
          <person-group person-group-type="author">
            <name><surname>Mukhamedjanov</surname><given-names>I.D.</given-names></name>
            <name><surname>Konstantinova</surname><given-names>A.M.</given-names></name>
            <name><surname>Loupian</surname><given-names>E.A.</given-names></name>
          </person-group>
          <article-title>The Use of Satellite Data for Monitoring Rivers in the Amu Darya Basin</article-title>
          <source>Regional Problems of Earth Remote Sensing</source>
          <year>2020</year>
          <volume>223</volume>
          <fpage>03008</fpage>
          <pub-id pub-id-type="doi">10.1051/e3sconf/202022303008</pub-id>
        </element-citation>
      </ref>
      <ref id="B13">
        <label>13.</label>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name><surname>Terekhov</surname><given-names>A.G.</given-names></name>
            <name><surname>Abayev</surname><given-names>N.N.</given-names></name>
            <name><surname>Sagatdinova</surname><given-names>G.N.</given-names></name>
            <name><surname>Mukhamediev</surname><given-names>R.I.</given-names></name>
            <name><surname>Amirgaliyev</surname><given-names>E.N.</given-names></name>
          </person-group>
          <article-title>Satellite Estimation of River Water Level from Shoal Monitoring Data: The Case of the Transboundary Ili River (Central Asia)</article-title>
          <source>Sovremennye Problemy Distantsionnogo Zondirovaniya Zemli iz Kosmosa</source>
          <year>2023</year>
          <volume>20</volume>
          <issue>4</issue>
          <fpage>227</fpage>
          <lpage>238</lpage>
          <pub-id pub-id-type="doi">10.21046/2070-7401-2023-20-4-227-238</pub-id>
          <comment>(in Russian)</comment>
        </element-citation>
      </ref>
      <ref id="B14">
        <label>14.</label>
        <element-citation publication-type="paper-conference">
          <person-group person-group-type="author">
            <name><surname>Suslin</surname><given-names>V.V.</given-names></name>
            <name><surname>Podgibailov</surname><given-names>E.A.</given-names></name>
            <name><surname>Martynov</surname><given-names>O.V.</given-names></name>
            <name><surname>Sholar</surname><given-names>S.A.</given-names></name>
          </person-group>
          <article-title>Water Discharge of the Danube River According to Medium-Resolution Optical Satellite Data</article-title>
          <source>Proceedings of the XII All-Russian Conference with International Participation "Current Problems in Optics of Natural Waters"</source>
          <year>2023</year>
          <volume>13</volume>
          <fpage>240</fpage>
          <lpage>245</lpage>
          <comment>(in Russian)</comment>
        </element-citation>
      </ref>
    </ref-list>
  </back>
</article>
