EO:EUM:DAT:1122

OLCI Total Column Water Vapour (TCWV) at Reduced Resolution (RR) - Sentinel-3

EUMETSAT has funded studies for developing Total Column Water Vapour (TCWV) retrievals from the OLCI instrument. Although the primary focus of OLCI is on ocean and land, the atmosphere has become important user driven application, both for atmospheric correction and deriving stand-alone dedicated atmospheric products. These developments have resulted in the TCWV product, also known as COWa (Copernicus Sentinel-3 OLCI Water vapour). The algorithm uses a 1D-Var optimal estimation scheme and multiple spectral bands around 0.9 microns. The output is produced in cloud-free daytime only, with a known higher information content above land (bright surface signal). Water vapour (H₂O) in the atmosphere is a key component of the Earth’s hydrological cycle, critical in shaping the global environment and supporting life on Earth as we know it. Manifold physical processes thereby help redistributing the water from the oceans to the land involving the formation of clouds, precipitation, and extreme weather events. Water vapour also has a key role in constraining the Earth’s energy balance. It is the single most important natural greenhouse gas in the atmosphere and constitutes a strong positive feedback to anthropogenic climate forcing from carbon dioxide (CO₂). The water vapour feedback is critically important in understanding past and determining future climate change and its global and regional impacts. This is a dedicated and standalone Sentinel-3 L2 Atmospheric TCWV product, directly driven by Meteorology and Numerical Weather Prediction (NWP) user needs. It differs from the historical TCWV product (see Collection EO:EUM:DAT:0553), based on the Integrated Water Vapour (IWV) parameter present in the OLCI L2 Marine product, and which is planned to be discontinued by 2028.

Satellite: Sentinel-3

Instrument: OLCI

Temporal Extent: 2026-06-16 - now

Orbit Type: LEO

Data Policy: Copernicus

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