Topic outline

  • New approaches and tools for performing ocean colour match-up analyses with OLCI

    Webinar with Ben Loveday, Hayley Evers-King, Juan Ignacio Gossn and Noemi Marsico (EUMETSAT)

    29 March 2023, 11:00 UTC | Register

    This advanced to expert level short course will focus on recent changes to data access for Sentinel-3 Ocean and Land Colour Instrument (OLCI) products, and introduce new tools and approaches for performing ocean colour match-up analyses.

    The event will:

    • present the available operational and reprocessed OLCI products through the EUMETSAT Data Store
    • detail web-based (GUI) and automated (API) methods to search for and retrieve these products
    • introduce the ThoMaS (Tool to generate Matchups of OC products with Sentinel-3/OLCI) toolkit for automating OLCI ocean colour data acquisition and match-up analysis
    • demonstrate the use of the tool using multiple example use cases.


    The short course will consist of a 2-hour webinar on March 29th (11:00 - 13:00 UTC), which will include a Q&A and feedback session. To support participants in using the ThoMaS toolkit, we will keep the online Q&A platform open for one week following the webinar, responding quickly to any queries posted. We will close the Q&A portion of the course with a second live feedback session on April 12th (11:00 - 13:00 UTC), giving those interested a chance to share their experiences using the tool, make recommendations for improvements or seek more advanced guidance on their specific workflows. Participants who attend the initial webinar will be automatically invited to the follow up session by email.

    Optional preparatory steps

    There are no prerequisites for this course, but if you intend to use the EUMETSAT Data Store and/or the ThoMaS toolkit, you will require the following; 

    • Searching for products in the EUMETSAT Data Store does not require authentication. However, in order to download products you will require a EUMETSAT Earth Observation Portal account. You can apply for one via this link
    • The ThoMaS toolkit is now available via the EUMETSAT Gitlab account. We encourage you to check the README for more information on using it.
    • The ThoMaS match-up routines require ancillary atmospheric data that is retrieved from ECMWF using their cdsapi. In order to use this, you will require accounts to use the CDS and ADS services.

    Target audience

    All attendees are welcome. However, the course is predominantly aimed at;

    • Established and early career ocean colour researchers
    • Operational oceanographers performing validation studies
    • Private and public sector specialists engaged in marine monitoring activities
    • Previous attendees of EUMETSAT Supporting Marine Applications courses that focussed on ocean colour applications

    At the end of the event, participants will:

    • Recall how to access the EUMETSAT Data Store and identify the Sentinel-3 OLCI products that it contains.
    • Use the EUMETSAT data access client (eumdac) to search for and retrieve Sentinel-3 OLCI products from the store via API.
    • Recall how to acquire and configure the EUMETSAT ThoMaS ocean colour match-up toolkit.
    • (Optionally) implement ThoMaS to perform match-up analyses using Sentinel-3 OLCI products.
    • (Optionally) evaluate the utility of the toolkit in the context of their own workflows.

    We look forward to seeing you at the course!

  • How to participate

    We'll meet you on Zoom Webinar 

    Zoom is a web-based video conferencing tool with a local, desktop client and a mobile app that allows us to meet online. 
    You do not need an account to join the session. To join, simply click the link provided when registering. (Troubles joining?)

    Here are a few tips you may consider:

    1. For better audio quality, please prepare a headset with a microphone.
    2. Join 5-10 minutes early to test your audio. Here is how to do it
    3. Use your real name. 

    Need help in Zoom?

    We want to make sure you get support when you need it. During the session, please use the Chat window and select Send to: Support to send a message to our colleagues who can help you. 

    Your questions on

    During the webinar, we will be using Slido to answer your questions. Go to and use #EUMSC35 or click hereNo log in required. You can join Slido from your phone.

  • Recording and resources

    Recording of the webinar:

    Data Store Access and EUMETSAT Data Access Client, presented by Noemi Marsico, EUMETSAT
    ThoMaS - a Tool to generate Matchups of OC products with Sentinel-3/OLCI, presented by Juan Ignacio Gossn, EUMETSAT

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