Global GNSS Integrated Water Vapour data, 1994-2020

This data set contains daily and monthly Integrated Water Vapour (IWV) data from a global network of 434 GNSS stations for the period 1994-2020. The GNSS data were processed by Center for Orbit Determination in Europe (CODE) in two batches: CODE REPRO_2015 for the period 1994-2014 (Susnik et al., 2016) and CODE operational solution for the period 2015-2020 (Dach et al., 2018). Both solutions were obtained by consistent processing with Bernese GNSS software v5.3 and included : GPS observations (1994..2001) and GPS+GLONASS (2002..2020). satellite ephemerids and clocks, ERPs, station coordinates and tropospheric parameters were estimated from one inversion of the normal equations based on a long-arc (3-days) solution (ftp.aiub.unive.ch/REPRO_2015; ftp.aiub.unive.ch/CODE). The Zenith Tropospheric Delay (ZTD) were estimated with a sampling of 2 hours. The ZTD data were post-processed by IPGP-IGN as follows: ZTD were screened (range-check and outlier check) and converted to IWV (ERA5 6-hourly pressure level data with bi-linear horizontal interpolation from the four surrounding grid points). Daily IWV values were computed as weighted means of 00, 06, 12, 18 UTC of the day and 00 UTC the next day. Monthly IWV values were computed from the 6-hourly data with a minimum of 60 values per month. More information about the post-processing can be found in Bock and Parracho (2019).