Aim of the GNSS4SWEC WG3:

• Collect and inter-compare various reprocessed GNSS tropospheric products,
• Develop, validate and exchange methods to convert between ZTD and IWV,
• Detect and mitigate discontinuities in the IWV time series due to changes in equipment,
• Establish a GNSS climate data record based on existing and reprocessed and homogenised tropospheric products,
• Inter-compare and quantify reprocessed GNSS tropospheric products witht geodetic, atmospheric in-situ and remote sensing techniques,
• Evaluate the accuracy of NWP reanalysis products and climate models,
• Assess relevant diagnostics and indexes for quantifying climate trends and variability,
• Bring together GNSS data owners, both private and public, on a European scale.

WG3 contribution Bulgaria

• Assessment of GNSS water vapour for the 2007 heat wave in Bulgaria,
• Inter-comparison of water vapour from reprocessed GNSS, ALADIN-Climate and ERA Interim.

WG3 members Bulgaria

• Biliana Mircheva - 2007 heatwave study with reprocessed GNSS tropospheric products,
• Guergana Guerova - ALADIN-Climate comparison.

GNSS4SWEC official web sites at: 1) KNMI and 2) COST.