Presentation by Eva Stierman and Marieke Eleveld (Deltares) at the Symposium Earth Observation and Data Science, during Delft Software Days - Edition 2017. Friday, 3 November 2017, Delft.

1. 13 november 2017
Open-access Sentinel processing: Demo
and case North Sea water quality
Eva Stierman & Marieke Eleveld

2. 13 november 2017
Content
• Introduction Sentinel 1,2,3
• Demo Copernicus Open Access Hub
• Demo SNAP mention possibilities for batch processing through
Java and Python
• Water Quality from Sentinel-3 OLCI

3. Sentinel satellite mission
• ESA develops satellite missions to monitor global environment
• Atmosphere
• Ocean
• Land
• Currently 4 types of Sentinel satellites
• Sentinel-1 Land and ocean monitoring (Radar)
• Sentinel-2 Land monitoring (Optical)
• Sentinel-3 Marine observation (Radar altimeter & Optical)
• Sentinel-5P Atmospheric monitoring (Optical)
• Launched: 13 October
13 november 2017
https://sentinels.copernicus.eu/web/sentinel/home

4. Data accessibility
• Deltares through EUMETCAST system
Intern on: “P:1000375-eumetcast-data”
• Copernicus Open Access Hub
https://scihub.copernicus.eu/
13 november 2017

5. Data processing using SNAP and snapPy
• SNAP (SeNtinel Application Platform)
• Toolboxes for Sentinel data processing
• Fast image display
• Statistics
http://step.esa.int/main/download/
• snapPy (Sentinel Application Platform)
• SNAP Java API from Python
• STEP (Science Toolbox Exploitation Platform)
13 november 2017

6. Case study: Water quality from Sentinel-3A OLCI
• In-situ measurements
• Sentinel-3A Ocean Land Colour Instrument (OLCI)
• What are the possibilities and limitations of
Sentinel-3A data products in monitoring water
quality of the Dutch North Sea?
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7. Case study: Overview in-situ measurement locations
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8. Case study: In-situ measurements
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9. Case study: Spectra water quality products
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• Chlorophyll
• Distinctive absorption spectrum
• Total Suspended Matter (TSM)
• Scattering in the whole VIS and
absorption in the blue

10. Case study: Chl and TSM products
13 november 2017
(Copyright 2017 EUMETSAT) of 9 July 2017 (Eva Stierman, Deltares).
Contains modified Copernicus Sentinel data 2017.

11. Case study: Chlorophyll regression with in-situ
13 november 2017
Match-up conditions:
• Coordinates in-situ
measurements and satellite
data are the same
• Invalid pixels were filtered out
• Time difference between in-situ
and satellite measurement
Chl (ug/l) match-up data
with time difference of
maximum 2 hours.

12. Case study: TSM regression with in-situ
13 november 2017
TSM (g/l) match-up data
with time difference of
maximum 2 hours.

13. Case study: Conclusions
• Chlorophyll obtained from the Neural Network of OLCI
Sentinel-3A correlates well with the in-situ measurements when the time
difference was less than 1 day.
• TSM obtained from the Neural Network of OLCI
Sentinel-3A does not correlate well with in-situ measurements.
• Water-leaving radiance of OLCI correlates well, atmospheric parameters
show promising results when time difference is kept small.
• Further research recommendations:
• Radiative transfer models
• Lookup tables
• Vicarious calibrations
• Neural Networks
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14. Support the development of evidence-based policies
Chlorophyll as indicator of standing stock phytoplankton
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ICES boxes over the annual
geometric mean MERIS-
derived chlorophyll
concentration during the
growing season 15 Feb.15 to
15 Nov. 2003 (Peters et al.,
2005; Vermaat et al., 2008).
Development and
promotion of CMEMS
Downstream services
contributing to the
implementation of the
MSFD of the EU
(Eleveld, Blaas and
colleagues)
Eutrophication status of the
Greater North Sea (OSPAR
Region II) in the second
application of the OSPAR
Comprehensive Procedure for the
period 2001–2005 (OSPAR,
2010).