A data assimilation system combining CryoSat-2 data and hydrodynamic river models

Raphael Schneider, Marc Etienne Ridler, Peter Nygaard Godiksen, Henrik Madsen, Peter Bauer-Gottwein

Research output: Contribution to journalArticleResearchpeer-review

19 Citations (Scopus)

Abstract

There are numerous hydrologic studies using satellite altimetry data from repeat-orbit missions such as Envisat or Jason over rivers. This study is one of the first examples for the combination of altimetry from drifting-ground track satellite missions, namely CryoSat-2, with a river model. CryoSat-2 SARIn Level 2 data is used to improve a 1D hydrodynamic model of the Brahmaputra River in South Asia, which is based on the Saint-Venant equations for unsteady flow and set up in the MIKE HYDRO River software. After calibration of discharge and water level the hydrodynamic model can accurately and bias-free represent the spatio-temporal variations of water levels. A data assimilation framework has been developed and linked with the model. It is a flexible framework that can assimilate water level data which are arbitrarily distributed in time and space. The setup has been used to assimilate CryoSat-2 water level observations over the Assam valley for the years 2010–2015, using an Ensemble Transform Kalman Filter (ETKF). Performance improvement in terms of discharge forecasting skill was then evaluated. For experiments with synthetic CryoSat-2 data the continuous ranked probability score (CRPS) was improved by up to 32%, whilst for experiments assimilating real data it could be improved by up to 10%. The developed methods are expected to be transferable to other rivers and altimeter missions. The model setup and calibration is based almost entirely on globally available remote sensing data.

Original languageEnglish
Pages (from-to)197-210
Number of pages14
JournalJournal of Hydrology
Volume557
DOIs
Publication statusPublished - Feb 2018
Externally publishedYes

Keywords

  • CryoSat-2
  • Data assimilation
  • Hydrodynamic models
  • Rivers
  • Satellite altimetry

Programme Area

  • Programme Area 2: Water Resources

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