Synergy between satellite altimetry and optical water quality data towards improved estimation of lakes ecological status

Ave Ansper‐toomsalu, Krista Alikas, Karina Nielsen, Lea Tuvikene, Kersti Kangro

Research output: Contribution to journalJournal articleResearchpeer-review

1 Downloads (Pure)


European countries are obligated to monitor and estimate ecological status of lakes under European Union Water Framework Directive (2000/60/EC) for sustainable lakes’ ecosystems in the future. In large and shallow lakes, physical, chemical, and biological water quality parameters are influenced by the high natural variability of water level, exceeding anthropogenic variability, and causing large uncertainty to the assessment of ecological status. Correction of metric values used for the assessment of ecological status for the effect of natural water level fluctuation reduces the signal‐to‐noise ratio in data and decreases the uncertainty of the status estimate. Here we have explored the potential to create synergy between optical and altimetry data for more accurate estimation of ecological status class of lakes. We have combined data from Sentinel‐3 Synthetic Aperture Radar Altimeter and Cryosat‐2 SAR Interferometric Radar Altimeter to derive water level estimations in order to apply corrections for chlorophyll a, phytoplankton biomass, and Secchi disc depth estimations from Sentinel‐3 Ocean and Land Color Instrument data. Long‐term in situ data was used to develop the methodology for the correction of water quality data for the effects of water level applicable on the satellite data. The study shows suitability and potential to combine optical and altimetry data to support in situ measurements and thereby support lake monitoring and management. Combination of two different types of satellite data from the continuous Copernicus program will advance the monitoring of lakes and improves the estimation of ecological status under European Union Water Framework Directive.

Original languageEnglish
Article number770
JournalRemote Sensing
Issue number4
Number of pages23
Publication statusPublished - 2021

Bibliographical note

2021 by the authors.Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://


  • Altimetry data
  • Cryosat‐2
  • Ecological status class of lakes
  • European Union Water Framework Directive (2000/60/EC)
  • Optical data
  • Sentinel‐3
  • Shallow lakes
  • Synergy
  • Water level
  • Water quality parameters

Fingerprint Dive into the research topics of 'Synergy between satellite altimetry and optical water quality data towards improved estimation of lakes ecological status'. Together they form a unique fingerprint.

Cite this