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Arctic salinity from space: Monitoring the freshwater system.
  • +13
  • Justino Martínez,
  • Carolina Gabarró,
  • Veronica Gonzalez-Gambau,
  • Cristina González-Haro,
  • Estrella Olmedo,
  • Joaquim Ballabrera-Poy,
  • Antonio Turiel,
  • Rafael Catany,
  • Manuel Arias,
  • Rhiannon Davies,
  • Laurent Bertino,
  • Jiping Xie,
  • Roshin P. Raj,
  • Roberto Sabia,
  • Wenqing Tang,
  • Simon Yueh
Justino Martínez
Institute of Marine Sciences, CSIC

Corresponding Author:justino@icm.csic.es

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Carolina Gabarró
Barcelona Expert Center, Institute of Marine Sciences, CSIC
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Veronica Gonzalez-Gambau
Barcelona Expert Center, Institute of Marine Sciences, CSIC
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Cristina González-Haro
Institute of Marine Sciences, CSIC
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Estrella Olmedo
Barcelona Expert Center, Institute of Marine Sciences, CSIC
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Joaquim Ballabrera-Poy
Institute of Marine Sciences, CSIC
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Antonio Turiel
Institute of Marine Sciences, CSIC
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Rafael Catany
Argans Ltd.
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Manuel Arias
Argans Ltd.
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Rhiannon Davies
Argans Ltd.
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Laurent Bertino
Nansen Environmental and Remote Sensing Center
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Jiping Xie
Nansen Environmental and Remote Sensing Center
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Roshin P. Raj
Nansen Environmental and Remote Sensing Center
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Roberto Sabia
Telespazio-Vega for European Space Agency
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Wenqing Tang
Jet Propulsion Laboratory
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Simon Yueh
Jet Propulsion Laboratory
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Abstract

The Arctic Ocean contains only a 1% of the world’s ocean water, but the rivers that flow out into it account for the 10% of the volume world’s rivers freshwater. The upper layer of fresher water facilitates the creation of sea ice and plays an important role in the position of the jet stream and storms over the northern hemisphere [ISBN, 978-82-7971-097-4]. Remote sensing measurements are of special importance in the Arctic since in situ data is very scarce there. SMOS and SMAP are currently providing sea surface salinity (SSS) measures, but only the product provided by Barcelona Expert Center (BEC) is a dedicated product for the Arctic region. The product that we present in this work is an improvement of the BEC Arctic v2.0. The new version 3.0 has as the primary objective the describing better the river discharges. The spatial grid used is WGS84/NSIDC EASE-Grid 2.0 North for the all stages of the processing chain. This procedure avoids spatial interpolation, favoring the definition of river mouths. The salinity retrieval is based on the Debiased non-bayesian method [doi:10.1016/j.rse.2017.02.023] and similarly to what is done in the processing of altimetric data, SMOS salinity is corrected using a reference calculated from the own SMOS data for each latitude, longitude, pass orientation and antenna measuring position. Arctic v3.0 differs from current method [doi:10.3390/rs10111772] in two important points: the reference is computed for brightness temperature instead of SSS and the antenna has been divided in a more homogeneous grid. Other improvements concern to data filtering and propagation of the radiometric errors to SSS. All these improvements provide level 3 maps less noisy, increasing the effective resolution of salinity gradients. Freshwater gradients are much better resolved than in previous version (Fig. 1). Comparison with JPL SMAP product is also planned as a first step to generate a combined product. This work is funded by ESA Arctic + project and also includes the assimilation of the resulting SSS product in the ocean-sea ice data assimilation system TOPAZ as the next version TOPAZ5. A preliminary study [doi:10.5194/os-2018-163] has been performed concluding that BEC product could be a good candidate to be assimilated by TOPAZ. Moreover, some preliminary tests with a pre-release v3.0 version will start shortly.