1. IWF/ÖAW GRAZ Jason-2 Altimeter Calibration Status Quo Walter Hausleitner, Jörg Weingrill Altimeter Calibration Workshop 2010 Graz, Austria

2. IWF/ÖAW GRAZ Transponder Experiments  Transponder site on Gavdos, Greece  Jason-2 calibration –present status problems

3. IWF/ÖAW GRAZ Transponder site

4. IWF/ÖAW GRAZ Transponder instrument  Frequency / Bandwidth  Centre Frequ. 13.7 GHz  Bandwidth:600 MHz  Total gain:77 dB  Intrument delay:13.25 ns

5. IWF/ÖAW GRAZ Ocean vs. point target response

6. IWF/ÖAW GRAZ Point target response

7. IWF/ÖAW GRAZ Calibration data availability 2009 PassCal StatusData DateCycleOK / failS-IGDRSIMPACAL Cal. range comm.Aux. Data 09 09 1244OK YES 09 09 2245failYES 09 10 0146failYES 09 10 1147OK YES 09 10 2148no CAL 09 10 3149OK YES 09 11 1050OKYES 09 11 2051failYES 09 11 3052no CALYES 09 12 1053no CALYES 09 12 2054no CALYES 09 12 3055no CALYES 09 01 0956no CALYES 09 01 1957no CALYES

8. IWF/ÖAW GRAZ Calibration data availability 2010 PassCal StatusData DateCycleOK / failS-IGDRSIMPACAL Calibration Range commandAux. Data 10 01 2858failYES 10 02 0859no CALYES 10 02 1760failYES 10 02 2761no CALYES 10 03 0962OKYES 10 03 1963failYES 10 03 2964OKYES 10 04 0865failYES 10 04 1866failYES 10 04 2867no CALYES 10 05 0868OKYES 10 05 1769failYES 10 05 2770OKYES 10 06 0671OKYES 10 06 1672failYES

9. IWF/ÖAW GRAZ Data processing concept Reproduce obs. corr. Combine S-IGDR+Calibr. Interp. TRP meas. corr. Geometric Corr. Precise range residual Geophysical Corr. Atmospheric Corr. S-IGDR data extraction Calibration DataS-IGDR Compute absolute times Fit parabola to echo bins

10. IWF/ÖAW GRAZ S-IGDR  Sensor Interim Geophysical Data Records (S- IGDRR)  NetCDF Files from podaac.jpl.nasa.gov  1 Hz data + 20 Hz high-rate data  Waveforms  Latency: 2 days  Pass 018  Descending Gavdos pass Pass 018

11. IWF/ÖAW GRAZ S-IGDR  S-IGDRRm data records used  lat  lat_20hz  lon  lon_20hz  range_ku  range_20hz_ku  rad_wet_tropo_corr  model_dry_tropo_corr  iono_corr_alt_ku  sea_state_bias_ku  model_wet_tropo_corr  alt  alt_20hz  mean_sea_surface  solid_earth_tide  pole_tide  inv_bar_corr  hf_fluctuations_corr  net_instr_corr_range_ku

12. IWF/ÖAW GRAZ Jason-2 Calibration  S-IGDR error budget From Jason-2 Products Handbook

13. IWF/ÖAW GRAZ Calibration analysis concept 11 sec data gap 3 sec calibration waveforms  Computation of closest approach time from S-IGDR orbit  Identification of TRP echo bin for each elementary waveform  Parabola fit and determination of vertex  Tie vertex of parabola to closest orbit point for aligning the calibrations to the orbit  Derive absolute times for each TRP echo bin through the relative times given calibration interval and bin-size 

14. IWF/ÖAW GRAZ S-IGDR data interpolation

15. IWF/ÖAW GRAZ Poseidon-2 elementary calibration

16. IWF/ÖAW GRAZ TRP echo bin detection  Lagrange interpolation of TRP power response  Numerical differentiation and Gaussian curve fitting  Power dependent weighting for each bin

17. IWF/ÖAW GRAZ Closest approach time/distance  Parabola fitting through TRP echo bins  Determination of fractional calibration number at parabola vertex  Aligning vertex with absolute time of closest approach

18. IWF/ÖAW GRAZ Altimeter range command Date2009/11/10 Time14:19:34 Date Exec. CAL2Only known to integer seconds ? Ho4604232 LSB Ho.0073191518 m NSPEC3 NCAL32 3.125 ns NSPEC * 0.05100769

19. IWF/ÖAW GRAZ Ambiguity of cal range  Altimeter range command  34 km  Ambiguity = (18/PRF)*c/2  PRF = 2058.513239 Hz   1310 km Ambiguity + Calibration range  1344 km

20. IWF/ÖAW GRAZ Altitude vs. Ku-band range

21. IWF/ÖAW GRAZ Propagation and reflection effects Source Uncorr. effect Cycle 50 Corr. Wet Troposph 0-30 cm15 cm Dry troposphere 230 cm229.5 cm Iono troposphere 0.2-20 cm1.6 cm Sea state bias 0-20 cm8.8 cm

22. IWF/ÖAW GRAZ Corrected range    m

23. IWF/ÖAW GRAZ Sea surface height

24. IWF/ÖAW GRAZ Geophysical corrections Mean sea surface Solid Earth tide Geocentr. Ocean tide Pole tide height Inv. barom. height eff. HF fluctuations of SST

25. IWF/ÖAW GRAZ Geophysical corrections (cont’d)

26. IWF/ÖAW GRAZ Interpolation effects  There is a significant difference between either  interpolating the individual corrections and sum up the interpolated corrections  Summing up the corrections and interpolate the sum of corrections

27. IWF/ÖAW GRAZ Signal runtime corrections r Geoid Ellipsoid hShS Center of mass correction Altimeter instrument delay hThT h ref SST GPS Transponder/Altimetry Dry troposphere Wet troposphere Ionosphere Transponder delay Offset station marker Slant range correction Solid Earth tides Pole tides

28. IWF/ÖAW GRAZ TRP range residuals r Geoid Ellipsoid Calibration bin range Ambiguity Altimeter delay CoM Correction Dry troposphere Wet (water vapour) Ionosphere TRP delay (electronic) TRP delay (geometric) Station marker eccentricity Slant range correction TRP ell.height Solid earth tides Corrections EffectMagnitude (m) Orbital height Residual 33738.088 1310718.858 -5.173 0.471 - 3.972 -1.477 -0.824 251.169 -0.060 1344398.967 44.575 -2.297 -0.116 -0.016