<?xml version="1.0" encoding="UTF-8"?> <Spase xmlns="http://www.spase-group.org/data/schema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.spase-group.org/data/schema http://cdpp.irap.omp.eu/AMDA-NG/public/schemas/spase-amda-1_2_0.xsd"> <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> </Spase>