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    <Version>2.2.6</Version>
    <NumericalData>
        <ResourceID>spase://CDPP/NumericalData/AMDA/MEX/MARSIS/mex-marsis-ele</ResourceID>
        <ResourceHeader>

            <ResourceName>total electron content</ResourceName>

            <ReleaseDate>2015-10-15T10:14:00</ReleaseDate>

            <Description>The level 5 TEC data are derived following a method described in 
             details by Mouginot et al. Planetary Space Science, V56, 2008. 
             The correction method consists in finding the three parameters [ a1 ; a2 ; a3 ] 
             defining the signal distortion phase Δφ induced by the ionosphere. 
             In the time domain, the ionosphere distortion generates a delay and a spreading 
             of the radar pulse. It is clearly visible on MARSIS radargram without correction. 
             A by-product of the ionospheric correction is the TEC, that can be easily obtained
             from the [ a1 ; a2 ; a3 ] parameters. [ a1 ; a2 ; a3 ] are 
             investigated in ordrer to get Δφ with the best SNR As initial conditions for this
             optimization, we use the parameters fitting with a simplified Gaussian 
             density-profile of the ionosphere.
Then the optimization is done by using the following constraints:
 * A constraint on the vertical position of the surface echo estimated with the digital elevation model MOLA.
 * A constraint on the SNR. The signal amplitude must be maximal after correction.
</Description>
            <Contact> 
                <PersonID>spase://CDPP/Person/W.Kofman</PersonID>
                <Role>DataProducer</Role>

            </Contact>

            <Contact> 
                <PersonID>spase://CDPP/Person/C.Grima</PersonID>
                <Role>DataProducer</Role>
            </Contact> 
            <InformationURL>
        <Name>MARSIS TEC documentation</Name>
        <URL>ftp://psa.esac.esa.int/pub/mirror/MARS-EXPRESS/MARSIS/MEX-M-MARSIS-5-DDR-SS-TEC-V1.0/DOCUMENT/MARSIS_EAICD_TEC.PDF</URL>
      </InformationURL> 

        </ResourceHeader>
        <AccessInformation>
            <RepositoryID>spase://SMWG/Repository/CDPP/AMDA</RepositoryID>
            <Availability>Online</Availability>
            <AccessRights>Open</AccessRights>
            <AccessURL>
                <URL>http://amda.cdpp.eu</URL>
            </AccessURL>
            <Format>NetCDF</Format>
        </AccessInformation>

        <ProviderName>PSA</ProviderName>
        <ProviderResourceName>MEX-M-MARSIS-5-DDR-SS-TEC-[EXT1]-V1.0</ProviderResourceName>
        <ProviderProcessingLevel>L5</ProviderProcessingLevel>

        <InstrumentID>spase://CDPP/Instrument/AMDA/MEX/MARSIS</InstrumentID>

        <MeasurementType>Waves</MeasurementType>

        <TemporalDescription>
            <TimeSpan>

                <StartDate>2005-06-19T04:03:28Z</StartDate>
                <StopDate>2007-09-30T23:41:11Z</StopDate>

            </TimeSpan>
            <Cadence_Min>PT1S</Cadence_Min>
            <Cadence_Max>PT10S</Cadence_Max>
        </TemporalDescription>

        <ObservedRegion>Mars</ObservedRegion>

        <Caveats>Data Quality Description :

              * -1: percentage of low SNR data not available
              * 0: no low SNR data                         
              * 1: less than 25% low SNR data               
              * 2: less than 50% low SNR data              
              * 3: less than 75% low SNR data               
              * 4: more than 75% low SNR data       
        </Caveats>        

        <Parameter>
            <Name>tec</Name>
            <ParameterKey>mex_marsis_tec</ParameterKey>

            <Description>Total electron content derived from the ionosphere        
                   distortion correction</Description>

            <Ucd>phys.density;phys.electron</Ucd>

            <Units>m-2</Units>

            <RenderingHints>
                <DisplayType>TimeSeries</DisplayType>
            </RenderingHints>
            <Support>
                <SupportQuantity>Other</SupportQuantity>
            </Support>
        </Parameter>

        <Parameter>
            <Name>quality flag</Name>
            <ParameterKey>mex_marsis_tecflag</ParameterKey>
            <Description/>
            <Ucd/>
            <Units/>
            <RenderingHints>
                <DisplayType>TimeSeries</DisplayType>
            </RenderingHints>
            <Support>
                <SupportQuantity>Other</SupportQuantity>
            </Support>
        </Parameter>

     </NumericalData>
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