Global GNSS IWV data at 436 stations over the 1994-2018 period

Global GNSS IWV data at 436 sites built up from CODE REPRO_2015 solution for the period 1994-2014 and CODE operational solution for the period 2005-2018. Summary of data processing details: Bernese GNSS software v5.3 ; observations: GPS (1994..2011) and GPS+GLONASS (2002..2018); ephemerids, ERPs, station coordinates, and tropospheric parameters estimated from one inversion of the normal equations based on a long-arc (3-days) solution. Full information about GNSS data processing can be found at : ftp.aiub.unive.ch/REPRO_2015 and ftp.aiub.unive.ch/CODE for both solutions. Summary of post-processing details: ZTD parameters (one every 2 hours) are screened based on a range-check and outlier check of ZTD values and formal errors and converted to IWV using ERA-Interim pressure level data (one every 6 hours) with bi-linear horizontal interpolation from 4 surrounding grid points. Daily IWV value is computed as a weighted mean of values valid at 00, 06, 12, 18 UTC of the day and 00 UTC the next day. Monthly IWV value is 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).