Evaluation of multi-mode CryoSat-2 altimetry data over the Po River against in situ data and a hydrodynamic model

Raphael Schneider, Angelica Tarpanelli, Karina Nielsen, Henrik Madsen, Peter Bauer-Gottwein

Research output: Contribution to journalArticleResearchpeer-review

27 Citations (Scopus)


Coverage of in situ observations to monitor surface waters is insufficient on the global scale, and decreasing across the globe. Satellite altimetry has become an increasingly important monitoring technology for continental surface waters. The ESA CryoSat-2 altimetry mission, launched in 2010, has two novel features. (i) The radar altimeter instrument on board of CryoSat-2 is operated in three modes; two of them reduce the altimeter footprint by using Delay-Doppler processing. (ii) CryoSat-2 is placed on a distinct orbit with a repeat cycle of 369 days, leading to a drifting ground track pattern. The drifting ground track pattern challenges many common methods of processing satellite altimetry data over rivers. This study evaluates the observation error of CryoSat-2 water level observations over the Po River, Italy, against in situ observations. The average RMSE between CryoSat-2 and in situ observations was found to be 0.38 meters. CryoSat-2 was also shown to be useful for channel roughness calibration in a hydrodynamic model of the Po River. The small across-track distance of CryoSat-2 means that observations are distributed almost continuously along the river. This allowed resolving channel roughness with higher spatial resolution than possible with in situ or virtual station altimetry data. Despite the Po River being extensively monitored, CryoSat-2 still provides added value thanks to its unique spatio-temporal sampling pattern.

Original languageEnglish
Pages (from-to)17-26
Number of pages10
JournalAdvances in Water Resources
Publication statusPublished - Feb 2018
Externally publishedYes


  • Calibration
  • CryoSat-2
  • River channel roughness
  • Rivers
  • Satellite altimetry
  • Validation

Programme Area

  • Programme Area 2: Water Resources


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