Today atmospheric remote sensing of the neutral atmosphere with space geodetic techniques is a very established field of research and applications thanks to the technological advances and developments of models and algorithms as well as the availability of regional and global ground-based networks and satellite-based missions. Water vapour is under sampled in current operational meteorological and climate observing systems. Advancements in Numerical Weather Prediction Models (NWP) (higher resolution and hourly cycling update), to improve forecasting of extreme precipitation, requires GNSS observations with a higher resolution in space and short delivery times than currently available. Homogeneously reprocessed GNSS observations on a regional and global scale have high potential for monitoring water vapour climatic trends and variability. Unfortunately, these time series suffer from inhomogeneities (for example instrumental changes, changes in the station environment) which can affect the analysis of the long-term variability. NWP data has recently been used for deriving new generation of mapping functions. In Real-Time GNSS processing there is currently an interest in using atmospheric NWP data to initialise Precise Point Positioning (PPP) processing algorithms, which can provide shorter convergence time and improve positioning.
We welcome, but not limit, contributions on the subjects below: Physical modelling of the neutral atmosphere using ground-based and radio-occultation data. Multi-GNSS, and multi-instruments approaches to retrieve and inter-compare tropospheric parameters. Real-Time and reprocessed tropospheric products for forecasting, now-casting and climate monitoring applications. Assimilation of GNSS measurements in weather forecasting (NWP and now-casting) and in climate models. Methods for homogenization of long-term dataset of GNSS tropospheric products. Studies on how to mitigate atmospheric effects GNSS positioning and navigation, as well as observations at radio wavelengths. Usage of NWP data in PPP processing algorithms.