This dataset provides estimates of water vapour derived from atmospheric delays in Global Navigation Satellite System
(GNSS) radio signals.
The initial data is collected from two in situ ground-based network of GNSS receivers – the International GNSS Service
(IGS) and EUREF Permanent Network (EPN). The IGS collects, archives, and freely distributes GNSS data from a
cooperatively operated global network of more than 500 ground-based GNSS stations since 1994. The EPN is a European
network of more than 300 continuously operating GNSS reference stations with precisely known coordinates.
The fundamental observable of ground-based GNSS is the Zenith Total Delay (ZTD). This observable represents the
propagation delay induced by the atmosphere on GNSS signals between the GNSS satellites and a GNSS receiver.
Using in-situ measurements of ZTD as well as ancillary meteorological data at the site, the vertically-integrated total
amount if water vapour in the air column can be retrieved. This integrated quantity is referred to as Total Column
Water Vapour (TCWV), or Precipitable Water Column (PWC), Total Precipitable Water (TPW),
or Integrated Precipitable Water (IPW), or also Integrated Water Vapour (IWV).
The TCWV values, with corresponding uncertainties, are available from the 2nd reprocessing campaign
of the EPN (EPN-repro2), the 3rd reprocessing campaign of the IGS (IGS-repro3), and the daily product of IGS.
All networks provide hourly records of ZTD as part of the products derived from GNSS data processing.
The GNSS TCWV derived from these ZTD data is a new product, made available exclusively for the Climate Data Store (CDS).
The data user must consider that while the EPN-repro2 and IGS-repro3 consist of tropospheric parameters derived from consistently
reprocessed data spanning multiple decades, the IGS daily product is a near real-time product which may contain jumps
in the time-series when a new processing model is introduced. Therefore, IGS daily ZTD and TCWV should not be considered
as reference products.
The method for retrieval of GNSS TCWV and details on the algorithms can be found in the documentation. For comparison,
TCWV values from the ECMWF ERA5 reanalysis are also made available for the user.
The datasets can be downloaded as NetCDF files (CDM-Obs-Core, see documentation) or as comma-separated values (CSV) files.
(GNSS) radio signals.
The initial data is collected from two in situ ground-based network of GNSS receivers – the International GNSS Service
(IGS) and EUREF Permanent Network (EPN). The IGS collects, archives, and freely distributes GNSS data from a
cooperatively operated global network of more than 500 ground-based GNSS stations since 1994. The EPN is a European
network of more than 300 continuously operating GNSS reference stations with precisely known coordinates.
The fundamental observable of ground-based GNSS is the Zenith Total Delay (ZTD). This observable represents the
propagation delay induced by the atmosphere on GNSS signals between the GNSS satellites and a GNSS receiver.
Using in-situ measurements of ZTD as well as ancillary meteorological data at the site, the vertically-integrated total
amount if water vapour in the air column can be retrieved. This integrated quantity is referred to as Total Column
Water Vapour (TCWV), or Precipitable Water Column (PWC), Total Precipitable Water (TPW),
or Integrated Precipitable Water (IPW), or also Integrated Water Vapour (IWV).
The TCWV values, with corresponding uncertainties, are available from the 2nd reprocessing campaign
of the EPN (EPN-repro2), the 3rd reprocessing campaign of the IGS (IGS-repro3), and the daily product of IGS.
All networks provide hourly records of ZTD as part of the products derived from GNSS data processing.
The GNSS TCWV derived from these ZTD data is a new product, made available exclusively for the Climate Data Store (CDS).
The data user must consider that while the EPN-repro2 and IGS-repro3 consist of tropospheric parameters derived from consistently
reprocessed data spanning multiple decades, the IGS daily product is a near real-time product which may contain jumps
in the time-series when a new processing model is introduced. Therefore, IGS daily ZTD and TCWV should not be considered
as reference products.
The method for retrieval of GNSS TCWV and details on the algorithms can be found in the documentation. For comparison,
TCWV values from the ECMWF ERA5 reanalysis are also made available for the user.
The datasets can be downloaded as NetCDF files (CDM-Obs-Core, see documentation) or as comma-separated values (CSV) files.
Interval
DOI
10.24381/cds.34a04494
Portal
Climate Data Store
Product Family
Data
Product Type
In-situ observations
Provider
Copernicus C3S
Spatial Coverage
Global
Temporal Coverage
Past
Present
Variable Domain
Atmosphere (upper air)