1. 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.

2. GFZ Contribution

3. 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)

4. 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

5. 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)

6. 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

7. Multi-GNSS GFZ Activities
Since November 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/

8. Multi-GNSS High-resolution Tropospheric Gradients88
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).

9. Long-term variations in IWV/Temperature time series99
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

10. Contribution of German Weather Service DWD in cooperation with GFZ

11. 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

12. 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

13. GFZ cooperation with University Cologne

14. 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 at 25 GPS stations

15. Thank you very much!