EUMETSAT Profiles the Scientist Readying Sentinel-3C's Ocean Data Chain

EUMETSAT has published a profile of Dr Estelle Obligis, the scientist coordinating its scientific teams on the Copernicus Sentinel-3 mission, as the European satellite agency prepares for the launch of Copernicus Sentinel-3C, which it says is planned for later this year. The feature, written by Sarah Puschmann and dated 30 July 2026, is part of a series introducing the people working behind the mission.

According to EUMETSAT, Obligis holds a dual role as Marine Applications Competence Area Manager and deputy to the head of the organisation's scientific division. Her responsibilities include coordinating the scientific teams working on Sentinel-3 and supporting the preparations for bringing the new satellite into service. EUMETSAT says she came to the agency with twenty years of scientific and management experience from Collecte Localisation Satellites, a subsidiary of the French space agency.

What Sentinel-3C is meant to do

EUMETSAT describes the Copernicus Sentinel-3 mission as carrying three main instruments that collect observations of the ocean and the atmosphere. The ocean parameters it lists — chlorophyll, sea level, wind, waves and sea surface temperature — are described by the agency as essential inputs for ocean forecast models, maritime security and climate monitoring. Sea surface temperature and sea level are the same families of measurement that underpin the long-term ocean records used in ENSO monitoring, which depends on uninterrupted time series rather than one-off snapshots.

Continuity is the mission's stated purpose. EUMETSAT says the first two satellites in the series, Copernicus Sentinel-3A and -3B, are currently in orbit, and that Sentinel-3C will replace -3A, contributing to the long-term continuity of a mission the agency expects to last into the 2030s.

The agency says Obligis and its scientific teams are preparing the algorithms that convert raw satellite observations into high-quality geophysical products, giving wind speed at the sea surface, the concentration of chlorophyll and the radiative power of wildfires as examples. EUMETSAT adds that the teams also verify product quality by comparing the satellite retrievals against ground-based measurements and observations from other satellites, and that products are updated over time to reflect scientific advances and the changing needs of users. Those users, the agency says, include the Copernicus Marine Service, implemented by Mercator Ocean International as part of the Copernicus Programme, and the Copernicus Atmosphere Monitoring Service, implemented by the European Centre for Medium-Range Weather Forecasts as part of the same programme.

A method from the 1990s still in the processing chain

EUMETSAT traces Obligis's route into satellite oceanography to 1998, when Dr Laurence Eymard invited her to work on the European Space Agency's Environmental Satellite (ENVISAT) mission at her remote sensing and atmospheric science laboratory in Paris. Obligis, who had completed a PhD in microwave radiometry, worked on the ENVISAT microwave radiometer, which EUMETSAT describes as a highly sensitive sensor that measured atmospheric humidity.

"Laurence was an excellent scientist, willing to share her knowledge, and very open and curious about new topics," Obligis said in the EUMETSAT feature. She recalled that almost thirty years ago the pair began investigating artificial intelligence and neural networks to retrieve water vapour and sea surface salinity, at a time when "a lot of experts in our community were very sceptical." According to Obligis, the approach they developed then "is still being used as part of our Sentinel-3 operational processing today."

She also pointed to the practical difficulty of the current phase. "Our operational users rely on high-quality data from Sentinel-3A and -3B, so it is particularly challenging to continue to support the operations of these two satellites while at the same time preparing everything needed to bring Sentinel-3C into the fleet," Obligis told EUMETSAT.

The agency quotes her as saying that the arrival of first data remains the moment scientists wait for: "It is always incredibly exciting for us scientists to see the first data coming from the instruments once the satellite is in orbit." She cautioned in the same feature that considerable work on calibration and product delivery would still follow, but said real observations "demonstrate the potential of the mission."

The full profile is available on the EUMETSAT website. Related entries in the series cover EUMETSAT colleagues Ed Trollope and Milen Tahtadjiev.