[G06-1] Troposphere monitoring I

[G06-1-05] Heterogeneity of residuals from GNSS and ray-traced tropospheric delays as an indicator of hydrometeors

^○Pawel Hordyniec, Witold Rohm, Jan Kaplon (Wroclaw University of Environmental and Life Sciences, Institute of Geodesy and Geoinformatics, Wroclaw, Poland)

We attempt to indicate hydrometeors content along ray-path trajectories between ground-based receivers and respective GNSS satellites. Using tropospheric delays retrieved from GNSS data in Precise Point Positioning (PPP) and associated ray-traced delays in Numerical Weather Prediction (NWP) model, we are able to calculate residuals resulting from different processing approaches. When precise satellite orbits and clocks are applied, GNSS post-fit residuals carry the troposphere information except of multipath and residual antenna Phase Centre Variations (PCVs). After post-fit residuals are reduced by site-dependent systematic effect, they are introduced to GNSS-based delays increasing discrepancies with respect to ray-traced delays. Assuming the hydrometeor information in GNSS solution is correct, we expect the effect to be significant during severe weather events since ray-traced tropospheric delays exclude aerosols contributions. We conducted spatial and temporal correlation analysis of the slant delay residuals (GNSS minus ray-traced) with weather phenomena recorded during the COST ES1206 GNSS4SWEC benchmark period (May 5th - June 29th, 2013). We also discuss results that arise from different GNSS PPP slant delay estimation approaches related to coordinates constraining and inclusion of ZTD horizontal gradients.