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dc.contributor.authorGabarró Prats, Carolina
dc.contributor.authorGonzalez Gambau, Verónica
dc.contributor.authorCorbella Sanahuja, Ignasi
dc.contributor.authorTorres Torres, Francisco
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions
dc.identifier.citationGabarro, C., Gonzalez, V., Corbella, I., Torres, F. Impact of the local oscillator calibration rate on the SMOS measurements and retrieved salinities. "IEEE transactions on geoscience and remote sensing", 02 Setembre 2013, vol. 51, núm. 9, p. 4633-4642.
dc.description.abstractThe local oscillators (LOs) of the Soil Moisture and Ocean Salinity mission payload are used to shift the operating frequency of the 72 receivers to an optimal intermediate frequency needed for the signal processing. The LO temperature variations produce phase errors in the visibility, which result in a blurring of the reconstructed brightness temperature (Tb) image. At the end of the commissioning phase, it was decided to calibrate the LO every 10 min while waiting for a more in-depth analysis. During short periods of time, the LOcalibration has been performed every 2 min to assess the impact of a higher calibration rate on the quality of the data. In this paper, by means of a decimation experiment, the relative errors of 6- and 10-min calibration interval data sets are estimated using the 2 min as a reference. A noticeable systematic across- and along-track pattern of amplitude ±0.3 K is observed for Tb differences between 10 and 2 min, whereas this is reduced between 6 and 2 min. A simulation experiment confirms that the nature of such systematic pattern is due to the visibility phase errors induced by the LO calibration rate. Such pattern is propagated into the sea surface salinity (SSS) retrievals. Overall, the SSS error increase (relative to the 2min SSS data) is about 0.39 and 0.14 psu for the 10- and 6-min data sets, respectively. This paper shows that a LO calibration rate of at least 6 min would noticeably improve the SSS retrievals.
dc.format.extent10 p.
dc.publisherInstitute of Electrical and Electronics Engineers (IEEE)
dc.subjectÀrees temàtiques de la UPC::Enginyeria de la telecomunicació::Radiocomunicació i exploració electromagnètica::Circuits de microones, radiofreqüència i ones mil·limètriques
dc.subject.lcshMicrowave communication systems
dc.subject.lcshSoil moisture--Measurement
dc.subject.otherBrightness temperature
dc.subject.otherMicrowave Imaging Radiometer by Aperture Synthesis (MIRAS)
dc.subject.otherSoil Moisture and Ocean Salinity (SMOS)
dc.titleImpact of the local oscillator calibration rate on the SMOS measurements and retrieved salinities
dc.subject.lemacSistemes de comunicació de microones
dc.subject.lemacSòls -- Humitat -- Mesurament
dc.contributor.groupUniversitat Politècnica de Catalunya. RF&MW - Grup de Recerca de sistemes, dispositius i materials de RF i microones
dc.contributor.groupUniversitat Politècnica de Catalunya. RSLAB - Grup de Recerca en Teledetecció
dc.description.peerreviewedPeer Reviewed
dc.rights.accessRestricted access - publisher's policy
dc.description.versionPostprint (published version)
local.citation.authorGabarro, C.; Gonzalez, V.; Corbella, I.; Torres, F.
local.citation.publicationNameIEEE transactions on geoscience and remote sensing

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