Global GNSS Integrated Water Vapour data based on NGL repro3, 1994-2022

This data set contains daily and monthly Integrated Water Vapour (IWV) data from a global network of more than 6000 GNSS stations having more than 10 years of observations over the period 1994-2022. The GNSS data were reprocessed by the Nevada Geodetic Laboratory (NGL) (Blewitt et al., 2018) using the GIPSY-X software. The Zenith Tropospheric Delay (ZTD) were natively estimated with a sampling of 5 minutes. The data were post-processed by IPGP-IGN as follows: 1) ZTD data were averaged into daily bins with a minimum of 50% of data available per day, 2) ZTD data were converted to IWV using daily ERA5 pressure level data extracted at the four surrounding grid points and bi-linearly interpolated to the latitude/longitude coordinates of each GNSS station, 3) daily IWV data were screened for outliers with a new methodology based on : i) the detection of jumps in the GNSS formal errors and ii) the GNSS – ERA5 departures (with a 3.5-sigma threshold around a 60-day running median), 4) monthly IWV values were computed as the means of daily values with at least 15 valid data per month