Recent GNSS activities in Germany for COST G. Dick1 F. Alshawaf1, Z. Deng1, X. Li1 , F. Zus1 , J. Wickert1, R. Potthast2, M. Bender2, S. Crewell3, S. Steinke3 1GFZ German Research Centre for Geosciences 2German Weather Service DWD 3University Cologne COST GNSS4SWEC Workshop and MC Meeting March 8-10, 2016 Reykjavik, Iceland COLAGE invited talk: When: April 2 (Friday) at Conference (Atibaia city): Subject: General information of CHAMP mission, Application of GPS occultation data to retrieve TEC, Temperature profile and water vapor, and CHAMP data bank. Audience: South America's Space geophysics community and Graduate students.

GFZ Contribution

Operational ZTD/IWV/STD Monitoring at GFZ in NRT D Hurricane Xaver December 8, 2013 Severe weather warning for Hamburg Hourly processing of GNSS data of ~300 stations (SAPOS network) Delay < 30 min after the last epoch of hour (near real-time)

Pre-operational NRT Processing EPOS8 software (updated models), PPP strategy ZTD/IWV/STD/Gradi products, GPS only, GLONASS will be included ~450 stations in processing (SAPOS + EUREF+ global IGS stations) pre-operational test run since January 2014 goal: uploading to E-GVAP STDs delivered to DWD for testing of STD assimilation operator D

Real-time processing ZTD products, GPS only, GLO+GAL+BeiDou will be possible 15 Bavarian SAPOS stations in processing since August 2014 30 EPN/IGS sites included for COST RT demonstration campaign since April 2015 Example: real time ZTDs for BRST (September 2015)

COST Benchmark Processing EPOS8 software, PPP strategy, GPS only ~550 stations processed (Benchmark + global IGS stations) post-processing (daily) / simulated NRT mode (12h sliding window) ZTD/IWV/STD/gradients products slants with and without residuals future plans: GLONASS + simulated RT D

Multi-GNSS GFZ Activities Since November 2015 GFZ provides ultra-rapid multi-GNSS orbit and clock product (GBU) for every 3 hour; Includes GPS, GLO, GAL, BDS and QZSS satellites; Latency is less than 2 hours since the last observation. Orbit & Clock differences: GBU (00:00 run, 6 hours prediction part) vs GBM ftp://ftp.gfz-potsdam.de/GNSS/products/mgex/

Multi-GNSS High-resolution Tropospheric Gradients 88 Multi-GNSS High-resolution Tropospheric Gradients We expect that the improved observation geometry allows a more robust and accurate estimation of ZTDs and horizontal delay gradients... Reference: Horizontal Delay Gradients from a NWM refractivity field (ECMWF analysis) Li et al. 2015, Retrieving high-resolution tropospheric gradients from multi-GNSS observations, GRL. The reference Horizontal Delay Gradients stem from a NWM refractivity field (ECMWF analysis).

Long-term variations in IWV/Temperature time series 99 Long-term variations in IWV/Temperature time series Monitoring atmospheric variables: Temperature Precipitable water vapor Precipitation Ice and snow GNSS, meteorological data, reanalysis and model data Site 0897 Berlin Airport 0.488 mm/decade 0.33 °C/decade

Contribution of German Weather Service DWD in cooperation with GFZ

Assimilation of STD observations Focus: Improving the humidity distribution in NWP models by assimilation of STD observations Strategy: Validating the impact of STD/ZTD data on weather forecasts STD assimilation Operator has interfaces to all DWD models (GME/ICON, COSMO-DE) and works with the corresponding assimilation systems (LETKF and 3d-Var) Current status: Assimilation experiments with COSMO Tuning of the assimilation system (LETKF) and validation of the forecast quality Goal: Operational STD assimilation 11

STD Observation Statistics STD assimilation experiment with COSMO-DE/KENDA: Two weeks: 16 May 2014 – 1 June 2014 Assimilation of conventional data and GPS STDs

GFZ cooperation with University Cologne

Evaluation of diurnal cycle of IWV in COSMO-REA Mean diurnal cycle of IWV measured with GPS and simulated with COSMO-REA during spring and summer 2007-2013 at 25 GPS stations

Thank you very much!