MATHEMATICAL AND PHYSICAL APPROACHES TO INFER ABSOLUTE ZENITH WET DELAYS FROM DOUBLE DIFFERENTIAL INTERFEROMETRIC OBSERVATIONS USING ERA5 ATMOSPHERIC REANALYSIS

Temperature changes make the ground and GNSS monuments expand and contract, producing millimetre-level vertical signals in station height time series. We release an open global dataset of temperature-driven vertical thermoelastic displacement for ~15,000 stations (2000–2023), computed from hourly temperature fields and site-specific soil and rock properties. The dataset helps improve the consistency of GNSS height time series for long-term land-motion studies.

Water vapour plays an important role in various weather and climate processes. However, due to its large spatiotemporal variability, its high-accuracy quantification remains a challenge. In this study, 20+ years of GPS-derived integrated water vapour (IWV) retrievals in Europe were obtained. They were then used to characterise the temporal features of Europe's IWV and assess six atmospheric reanalyses. Results show that ERA5 outperforms the other reanalyses at most temporal scales.

We developed a 5 min global integrated water vapour (IWV) product from 12 552 ground-based GPS stations in 2020. It contains more than 1 billion IWV estimates. The dataset is an enhanced version of the existing operational GPS IWV dataset from the Nevada Geodetic Laboratory. The enhancement is reached by using accurate meteorological information from ERA5 for the GPS IWV retrieval with a significantly higher spatiotemporal resolution. The dataset is recommended for high-accuracy applications.

In this study, a comprehensive multi-disciplinary dataset for tropospheric water vapor was developed. Geodetic, photogrammetric, and atmospheric modeling and data fusion techniques were used to obtain maps of water vapor in a high spatial and temporal resolution. It could be shown that regional weather simulations for different seasons benefit from assimilating these maps and that the combination of the different observation techniques led to positive synergies.