Preliminary Assessment of SARAL/AltiKa Observations over the Ganges-Brahmaputra and Irrawaddy Rivers |
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| Authors: | F Frappart F Papa V Marieu Y Malbeteau F Jordy S Calmant |
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| Institution: | 1. Géosciences Environnement Toulouse (GET), Groupe de Recherches de Géodésie Spatiale (GRGS), UMR 5563, CNRS/IRD/Université de Toulouse, Observatoire Midi-Pyrénées, Toulouse, France;2. Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UMR 5566, CNES/CNRS/IRD/Université de Toulouse, Observatoire Midi-Pyrénées, Toulouse, Francefrederic.frappart@get.obs-mip.fr;4. Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UMR 5566, CNES/CNRS/IRD/Université de Toulouse, Observatoire Midi-Pyrénées, Toulouse, France;5. Indo-French Cell for Water Sciences (IFCWS), IISc-NIO-IITM-IRD International Joint Laboratory, Bangalore, India;6. Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), UMR 5805, CNRS, Université de Bordeaux, Pessac, France;7. Centre d'Etudes Spatiales de la Biosphère (CESBIO), CNES/CNRS/IRD/UPS, Toulouse, France;8. Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UMR 5566, CNES/CNRS/IRD/Université de Toulouse, Observatoire Midi-Pyrénées, Toulouse, France;9. Ecole Supérieure des Géomètres et Topographes (ESGT), Le Mans, France |
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| Abstract: | Radar altimetry has demonstrated strong capabilities for the monitoring of water levels of lakes, rivers and wetlands over the last 20 years. The Indo-French SARAL/AltiKa mission, launched in February 2013, is the first satellite radar altimetry mission to carry onboard a Ka-band sensor. We propose here to evaluate the potential of this new instrument for land hydrology through comparisons with other altimetry-derived stages and discharges in the Ganges-Brahmaputra and Irrawaddy river basins using its first year of data. Due to the lack of concomitant in situ measurements for the current period, Jason-2 data, previously evaluated against in situ gauge records, were used as reference. Comparisons between Jason-2 and SARAL-derived water levels and discharges, and Jason-2 and Envisat (which flew the same orbit as SARAL from 2002 to 2010)-derived ones, was performed. Time-series of only one year of SARAL-derived water levels and discharges present better performances (lower RMSE and higher R, generally greater than 0.95) than the ones derived from Envisat when compared with Jason-2. |
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| Keywords: | Satellite altimetry validation water level discharge |
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