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C-band Scatterometer (CScat): the first global long-term satellite radar backscatter data set with a C-band signal dynamic

hal.structure.identifierPeking University [Beijing]
hal.structure.identifierCentre d'études spatiales de la biosphère [CESBIO]
dc.contributor.authorTAO, Shengli
hal.structure.identifierSouth China Normal University
dc.contributor.authorAO, Zurui
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorWIGNERON, Jean-Pierre
hal.structure.identifierJet Propulsion Laboratory [JPL]
dc.contributor.authorSAATCHI, Sassan
hal.structure.identifierLaboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
dc.contributor.authorCIAIS, Philippe
hal.structure.identifierEvolution et Diversité Biologique [EDB]
dc.contributor.authorCHAVE, Jérôme
hal.structure.identifierCentre d'études spatiales de la biosphère [CESBIO]
dc.contributor.authorLE TOAN, Thuy
hal.structure.identifierLaboratoire sciences et technologies de l'information géographique [LaSTIG]
hal.structure.identifierCentre d'études spatiales de la biosphère [CESBIO]
dc.contributor.authorFRISON, Pierre-Louis
hal.structure.identifierPeking University [Beijing]
dc.contributor.authorHU, Xiaomei
hal.structure.identifierLawrence Berkeley National Laboratory [Berkeley] [LBNL]
dc.contributor.authorCHEN, Chi
hal.structure.identifierChongqing University [Chongqing]
dc.contributor.authorFAN, Lei
hal.structure.identifierZhengzhou University
dc.contributor.authorWANG, Mengjia
hal.structure.identifierPeking University [Beijing]
dc.contributor.authorZHU, Jiangling
hal.structure.identifierChinese Academy of Sciences [Beijing] [CAS]
dc.contributor.authorZHAO, Xia
hal.structure.identifierChinese Academy of Sciences [Beijing] [CAS]
dc.contributor.authorLI, Xiaojun
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorLIU, Xiangzhuo
hal.structure.identifierChinese Academy of Sciences [Beijing] [CAS]
dc.contributor.authorSU, Yanjun
hal.structure.identifierChinese Academy of Sciences [Beijing] [CAS]
dc.contributor.authorHU, Tianyu
hal.structure.identifierPeking University [Beijing]
dc.contributor.authorGUO, Qinghua
hal.structure.identifierPeking University [Beijing]
dc.contributor.authorWANG, Zhiheng
hal.structure.identifierPeking University [Beijing]
dc.contributor.authorTANG, Zhiyao
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorLIU, Yi
hal.structure.identifierPeking University [Beijing]
dc.contributor.authorFANG, Jingyun
dc.date.accessioned2024-04-08T11:38:22Z
dc.date.available2024-04-08T11:38:22Z
dc.date.issued2022-08-15
dc.identifier.issn1866-3508
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/195022
dc.description.abstractEnAbstract. Satellite radar backscatter contains unique information on land surface moisture, vegetation features, and surface roughness, and can be acquired in all weather conditions, thus has been used in a range of earth science disciplines. However, there is no single global radar data set that spans more than two decades. This has limited the use of radar data for trend analysis over extended time intervals. We here provide the first long-term (since 1992), high resolution (~8.9 km) satellite radar backscatter data set over global land areas, the C-band Scatterometer (CScat) data set, by fusing signals from European Remote Sensing satellite (ERS, 1992–2001, C-band, 5.3 GHz), Quick Scatterometer (QSCAT, 1999–2009, Ku-band, 13.4 GHz), and the Advanced Scatterometer (ASCAT, since 2007, C-band, 5.255 GHz). The six-year data gap between C-band ERS and ASCAT was filled out by modelling an equivalent C-band signal during 1999–2009 from Ku-band QSCAT signals and climatic information. Towards this purpose, we first rescaled the signals from different sensors, pixel by pixel, using a new signal rescaling method that is robust to limited overlapping observations among sensors. We then corrected the monthly signal differences between the C-band and the scaled Ku-band signals, by modelling the signal differences from climatic variables (i.e., monthly precipitation, skin temperature, and snow depth) using decision tree regression. The quality of the merged radar signal was assessed by computing the Pearson r, Root Mean Square Error (RMSE), and relative RMSE (rRMSE) between the C-band and the corrected Ku-band signals in the overlapping years (1999–2001 and 2007–2009). We obtained high Pearson r values and low RMSE values at both the regional (r ≥ 0.93, RMSE ≤ 0.16, rRMSE ≤0.37) and pixel levels (median r across pixels ≥ 0.80, median RMSE ≤ 0.38, median rRMSE ≤ 0.64), suggesting high accuracy for the data merging procedure. The merged radar signal was then validated with a continuous ERS-2 data set available between 1995 and 2011. ERS-2 stopped working in full mode after 2001 but observations are occasionally available for a subset of the pixels until 2011. Because the period of 1995–2011 fully overlaps with the working period of QSCAT (1999–2009), comparing the merged radar signal against the ERS-2 data in 1995–2011 is the most direct validation available. We found concordant monthly dynamics between the merged radar signals and the ERS-2 signals during 1995–2011, with Pearson r value ranging from 0.79 to 0.98 across regions. These results evidenced that our merged radar data have a consistent C-band signal dynamic. The CScat data set (https://doi.org/10.6084/m9.figshare.20407857, Tao et al. 2022a) is expected to advance our understanding of the long-term changes in, e.g., global vegetation and soil moisture. The data set will be updated on a regular basis.
dc.language.isoen
dc.publisherCopernicus Publications
dc.title.enC-band Scatterometer (CScat): the first global long-term satellite radar backscatter data set with a C-band signal dynamic
dc.typeArticle de revue
dc.identifier.doi10.5194/essd-2022-264
dc.subject.halSciences de l'environnement
bordeaux.journalEarth System Science Data
bordeaux.hal.laboratoriesInteractions Soil Plant Atmosphere (ISPA) - UMR 1391*
bordeaux.institutionBordeaux Sciences Agro
bordeaux.institutionINRAE
bordeaux.peerReviewedoui
hal.identifierhal-04428638
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-04428638v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Earth%20System%20Science%20Data&rft.date=2022-08-15&rft.eissn=1866-3508&rft.issn=1866-3508&rft.au=TAO,%20Shengli&AO,%20Zurui&WIGNERON,%20Jean-Pierre&SAATCHI,%20Sassan&CIAIS,%20Philippe&rft.genre=article


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