<?xml version="1.0" encoding="UTF-8"?>
<gmd:MD_Metadata xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xmlns:gco="http://www.isotc211.org/2005/gco"
                 xmlns:gmd="http://www.isotc211.org/2005/gmd"
                 xmlns:srv="http://www.isotc211.org/2005/srv"
                 xmlns:gmx="http://www.isotc211.org/2005/gmx"
                 xmlns:gts="http://www.isotc211.org/2005/gts"
                 xmlns:gsr="http://www.isotc211.org/2005/gsr"
                 xmlns:gmi="http://www.isotc211.org/2005/gmi"
                 xmlns:gml="http://www.opengis.net/gml"
                 xmlns:xlink="http://www.w3.org/1999/xlink"
                 xsi:schemaLocation="http://www.isotc211.org/2005/gmd http://www.isotc211.org/2005/gmx/gmx.xsd">
   <gmd:fileIdentifier>
      <gco:CharacterString>edu.ucar.opensky::articles:27166</gco:CharacterString>
   </gmd:fileIdentifier>
   <gmd:language>
      <gmd:LanguageCode codeList="http://www.loc.gov/standards/iso639-2/"
                        codeListValue="eng; USA"/>
   </gmd:language>
   <gmd:characterSet>
      <gmd:MD_CharacterSetCode codeListValue="utf8"
                               codeList="http://www.isotc211.org/namespace/resources/codeList.xml#MD_CharacterSetCode"/>
   </gmd:characterSet>
   <gmd:hierarchyLevel>
      <gmd:MD_ScopeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/codelist/ML_gmxCodelists.xml#MD_ScopeCode"
                        codeListValue="document"/>
   </gmd:hierarchyLevel>
   <gmd:contact>
      <gmd:CI_ResponsibleParty>
         <gmd:organisationName>
            <gco:CharacterString>UCAR/NCAR - Library</gco:CharacterString>
         </gmd:organisationName>
         <gmd:positionName>
            <gco:CharacterString>OpenSky Support</gco:CharacterString>
         </gmd:positionName>
         <gmd:contactInfo>
            <gmd:CI_Contact>
               <gmd:address>
                  <gmd:CI_Address>
                     <gmd:deliveryPoint>
                        <gco:CharacterString>PO Box 3000</gco:CharacterString>
                     </gmd:deliveryPoint>
                     <gmd:city>
                        <gco:CharacterString>Boulder</gco:CharacterString>
                     </gmd:city>
                     <gmd:administrativeArea>
                        <gco:CharacterString>CO</gco:CharacterString>
                     </gmd:administrativeArea>
                     <gmd:postalCode>
                        <gco:CharacterString>80307-3000</gco:CharacterString>
                     </gmd:postalCode>
                     <gmd:electronicMailAddress>
                        <gco:CharacterString>opensky@ucar.edu</gco:CharacterString>
                     </gmd:electronicMailAddress>
                  </gmd:CI_Address>
               </gmd:address>
               <gmd:onlineResource>
                  <gmd:CI_OnlineResource>
                     <gmd:linkage>
                        <gmd:URL>http://opensky.ucar.edu/</gmd:URL>
                     </gmd:linkage>
                     <gmd:name>
                        <gco:CharacterString>homepage</gco:CharacterString>
                     </gmd:name>
                  </gmd:CI_OnlineResource>
               </gmd:onlineResource>
            </gmd:CI_Contact>
         </gmd:contactInfo>
         <gmd:role>
            <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode>
         </gmd:role>
      </gmd:CI_ResponsibleParty>
   </gmd:contact>
   <gmd:dateStamp>
      <gco:DateTime>2025-12-24T18:50:33.587889</gco:DateTime>
   </gmd:dateStamp>
   <gmd:metadataStandardName>
      <gco:CharacterString>ISO 19115-2 Geographic Information - Metadata - Part 2:
                    Extensions for Imagery and Gridded Data</gco:CharacterString>
   </gmd:metadataStandardName>
   <gmd:metadataStandardVersion>
      <gco:CharacterString>ISO 19115-2:2009(E)</gco:CharacterString>
   </gmd:metadataStandardVersion>
   <gmd:dataSetURI>
      <gco:CharacterString>https://n2t.org/ark:/85065/d7dr30pj</gco:CharacterString>
   </gmd:dataSetURI>
   <gmd:identificationInfo>
      <gmd:MD_DataIdentification>
         <gmd:citation>
            <gmd:CI_Citation>
               <gmd:title>
                  <gco:CharacterString>Enhanced aerosol mass in the tropical tropopause layer linked to ozone abundance</gco:CharacterString>
               </gmd:title>
               <gmd:date>
                  <gmd:CI_Date>
                     <gmd:date>
                        <gco:DateTime>2024-04-28T00:00:00Z</gco:DateTime>
                     </gmd:date>
                     <gmd:dateType>
                        <gmd:CI_DateTypeCode codeList="codeListLocation#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode>
                     </gmd:dateType>
                  </gmd:CI_Date>
               </gmd:date>
               <gmd:identifier>
                  <gmd:RS_Identifier>
                     <gmd:code>
                        <gco:CharacterString>https://n2t.org/ark:/85065/d7dr30pj</gco:CharacterString>
                     </gmd:code>
                  </gmd:RS_Identifier>
               </gmd:identifier>
               <gmd:identifier>
                  <gmd:RS_Identifier>
                     <gmd:code>
                        <gco:CharacterString>https://doi.org/10.1029/2023GL107451</gco:CharacterString>
                     </gmd:code>
                  </gmd:RS_Identifier>
               </gmd:identifier>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:individualName>
                        <gco:CharacterString>LIU, S.</gco:CharacterString>
                     </gmd:individualName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="author">author</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:individualName>
                        <gco:CharacterString>Thornberry, T. D.</gco:CharacterString>
                     </gmd:individualName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="author">author</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:individualName>
                        <gco:CharacterString>Yu, P.</gco:CharacterString>
                     </gmd:individualName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="author">author</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:individualName>
                        <gmx:Anchor xlink:href="https://orcid.org/0000-0003-2174-8889"
                                    xlink:title="Woods, Sarah"
                                    xlink:actuate="onRequest">Woods, Sarah</gmx:Anchor>
                     </gmd:individualName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="author">author</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:individualName>
                        <gco:CharacterString>Rosenlof, K. H.</gco:CharacterString>
                     </gmd:individualName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="author">author</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:individualName>
                        <gco:CharacterString>Gao, R.</gco:CharacterString>
                     </gmd:individualName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="author">author</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
               <gmd:citedResponsibleParty>
                  <gmd:CI_ResponsibleParty>
                     <gmd:organisationName>
                        <gco:CharacterString>UCAR/NCAR - Library</gco:CharacterString>
                     </gmd:organisationName>
                     <gmd:role>
                        <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="publisher">publisher</gmd:CI_RoleCode>
                     </gmd:role>
                  </gmd:CI_ResponsibleParty>
               </gmd:citedResponsibleParty>
            </gmd:CI_Citation>
         </gmd:citation>
         <gmd:abstract>
            <gco:CharacterString>Aerosol particles play a critical role in the tropical tropopause layer (TTL) through cloud formation and heterogeneous chemistry, influencing the radiative and chemical balance of the stratosphere. However, aerosol measurements in the TTL are sparse, resulting in poor knowledge of aerosol abundance and distribution in this important region. Here, we present in situ aircraft measurements over the western tropical Pacific, revealing a persistent and altitude-dependent enhancement of aerosol mass in the TTL compared to the convectively influenced troposphere below. Notably, our data demonstrate a striking positive correlation between aerosol mass and ozone. Model simulations suggest that organic materials constitute a substantial fraction of the total aerosol mass within the TTL. We further derived an empirical parameterization of TTL aerosol mass as a function of ozone based on their linear relationship. This framework holds potential for estimating the TTL aerosol abundance but requires further validation and refinement through future measurements.</gco:CharacterString>
         </gmd:abstract>
         <gmd:pointOfContact>
            <gmd:CI_ResponsibleParty>
               <gmd:organisationName>
                  <gco:CharacterString>UCAR/NCAR - Library</gco:CharacterString>
               </gmd:organisationName>
               <gmd:positionName>
                  <gco:CharacterString>OpenSky Support</gco:CharacterString>
               </gmd:positionName>
               <gmd:contactInfo>
                  <gmd:CI_Contact>
                     <gmd:address>
                        <gmd:CI_Address>
                           <gmd:deliveryPoint>
                              <gco:CharacterString>PO Box 3000</gco:CharacterString>
                           </gmd:deliveryPoint>
                           <gmd:city>
                              <gco:CharacterString>Boulder</gco:CharacterString>
                           </gmd:city>
                           <gmd:administrativeArea>
                              <gco:CharacterString>CO</gco:CharacterString>
                           </gmd:administrativeArea>
                           <gmd:postalCode>
                              <gco:CharacterString>80307-3000</gco:CharacterString>
                           </gmd:postalCode>
                           <gmd:electronicMailAddress>
                              <gco:CharacterString>opensky@ucar.edu</gco:CharacterString>
                           </gmd:electronicMailAddress>
                        </gmd:CI_Address>
                     </gmd:address>
                     <gmd:onlineResource>
                        <gmd:CI_OnlineResource>
                           <gmd:linkage>
                              <gmd:URL>http://opensky.ucar.edu/</gmd:URL>
                           </gmd:linkage>
                           <gmd:name>
                              <gco:CharacterString>homepage</gco:CharacterString>
                           </gmd:name>
                        </gmd:CI_OnlineResource>
                     </gmd:onlineResource>
                  </gmd:CI_Contact>
               </gmd:contactInfo>
               <gmd:role>
                  <gmd:CI_RoleCode codeList="codeListLocation#CI_RoleCode" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode>
               </gmd:role>
            </gmd:CI_ResponsibleParty>
         </gmd:pointOfContact>
         <gmd:resourceFormat>
            <gmd:MD_Format>
               <gmd:name>
                  <gco:CharacterString>PDF</gco:CharacterString>
               </gmd:name>
               <gmd:version/>
            </gmd:MD_Format>
         </gmd:resourceFormat>
         <gmd:descriptiveKeywords>
            <gmd:MD_Keywords>
               <gmd:keyword>
                  <gco:CharacterString>Text</gco:CharacterString>
               </gmd:keyword>
               <gmd:type>
                  <gmd:MD_KeywordTypeCode codeList="codeListLocation#MD_KeywordTypeCode" codeListValue="theme">theme</gmd:MD_KeywordTypeCode>
               </gmd:type>
               <gmd:thesaurusName>
                  <gmd:CI_Citation>
                     <gmd:title>
                        <gco:CharacterString>Resource Type</gco:CharacterString>
                     </gmd:title>
                     <gmd:date>
                        <gmd:CI_Date>
                           <gmd:date>
                              <gco:DateTime>2016-01-01T00:00:00Z</gco:DateTime>
                           </gmd:date>
                           <gmd:dateType>
                              <gmd:CI_DateTypeCode codeList="codeListLocation#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode>
                           </gmd:dateType>
                        </gmd:CI_Date>
                     </gmd:date>
                  </gmd:CI_Citation>
               </gmd:thesaurusName>
            </gmd:MD_Keywords>
         </gmd:descriptiveKeywords>
         <gmd:resourceConstraints>
            <gmd:MD_LegalConstraints>
               <gmd:useLimitation>
                  <gco:CharacterString>Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</gco:CharacterString>
               </gmd:useLimitation>
               <gmd:otherConstraints>
                  <gco:CharacterString>None</gco:CharacterString>
               </gmd:otherConstraints>
            </gmd:MD_LegalConstraints>
         </gmd:resourceConstraints>
         <gmd:language>
            <gmd:LanguageCode codeList="codeListLocation#LanguageCode" codeListValue="eng">eng</gmd:LanguageCode>
         </gmd:language>
         <gmd:topicCategory>
            <gmd:MD_TopicCategoryCode>geoscientificInformation</gmd:MD_TopicCategoryCode>
         </gmd:topicCategory>
      </gmd:MD_DataIdentification>
   </gmd:identificationInfo>
</gmd:MD_Metadata>
