The VAPOUR project will provide the next generation, space-geodetic, high-quality, spatiotemporal, asymmetric (Slant Total Delay (STD) in addition to legacy Zenith Total Delay (ZTD) and gradients (GRD)) tropospheric products, to improve numerical weather prediction (NWP) models for forecasting and derived re-analysis models on national and international levels. VAPOUR will employ Global Navigation Satellite System (GNSS) observations, including those of the European Galileo, and Synthetic Aperture Radar Interferometry (InSAR) data, such as from the Copernicus Sentinel missions.
The advanced products will take better account of the distribution of atmospheric water vapour within the troposphere, which is the most prominent greenhouse gas and is directly linked to precipitation and weather. Most current GNSS-derived tropospheric products do not fully account for these variations or suffer from unresolved issues such as multipath and the development of such products from SAR data is still largely experimental.

With the interest of the meteorological services for these products growing, VAPOUR is timely and highly relevant.