1. 21-23/04/2015PM27 ACRI-ST ARGANS LOCEAN TEC follow-up

2. overview 21/23-04-2015PM 27 Problem in some descending orbits : OTT is biased. Induce strong latitudinal SSS biases. -> diagnostic : L1c TEC not adapted for OTT computation.

3. 3 © ACRI-ST, all rights reserved – 2015 Faraday estimation using Stokes 3 L2OS processor retrieves TEC (together with SSS) assuming that TEC is constant along a dwell line.  valid assumption for ascending orbits : low TEC gradients  problem with OTT computation for descending orbits where TEC is high L2OS processor uses a priori information on TEC values. Descending orbits show strong Faraday variations due to strong TEC gradients. A priori information is sometimes biased in this case. → impact on SSS estimation ? Stokes 3 allows to retrieve TEC gradient Faraday rotation from SMOS data (descending orbits, 11/2011) Large Faraday rotation with strong TEC gradient Low Faraday rotation Lon Lat TEC retrieved from St3 L1c TEC Lat TEC From SMOS + polarimetry study PM27

4. 4 © ACRI-ST, all rights reserved – 2015 Comparison with forest Forest : TX-TY vanishes but A3 should vanish too. Statistics of A3/(TX-TY) tan(2.far)=A3/(TX-TY) From SMOS + polarimetry study PM27

5. 5 © ACRI-ST, all rights reserved – 2015 Exemple of TEC retrieval (0.15<eta<0.2) Sensitivity of A3 to TEC along the swath Coast ? PM27

6. 6 © ACRI-ST, all rights reserved – 2015 OTT1 std/ra using L1c TEC: 10 descending orbits HH/VVHH/VV short PM27

7. 7 © ACRI-ST, all rights reserved – 2015 OTT1 std/ra using A3 TEC: 10 descending orbits HH/VVHH/VV short PM27

8. 8 © ACRI-ST, all rights reserved – 2015 OTT1 std/ra using L1c TEC: 10 descending orbits HHV (Stokes 3 & 4) VVH (Stokes 3 & 4) PM27

9. 9 © ACRI-ST, all rights reserved – 2015 OTT1 std/ra using A3 TEC: 10 descending orbits HHV (Stokes 3 & 4) VVH (Stokes 3 & 4) PM27

10. 10 © ACRI-ST, all rights reserved – 2015 SSS differences (ref – A3TEC): ascending (May 2011) SSS differences close to the coast where the TEC is badly estimated. Swath signature which shows that the differences come from few orbits.

11. 11 © ACRI-ST, all rights reserved – 2015 SSS differences (ref – A3TEC): descending (May 2011) SSS differences with latitudinal signature.

12. 12 © ACRI-ST, all rights reserved – 2015 November 2011 : high TEC in ascending Highest TEC is not in Pacific but in South Atlantic A3 TEC ascending PM27

13. 13 © ACRI-ST, all rights reserved – 2015 Some hot spots correspond to coast/RFI or island contamination. Highest TEC is not in Pacific but in South Atlantic A3 TEC ascending PM27

14. 14 © ACRI-ST, all rights reserved – 2015 As expected, the A3TEC dynamic along the swath is not the same as the L1c TEC. A3 TEC ascending PM27

15. 15 © ACRI-ST, all rights reserved – 2015 GPS TEC issue or SMOS A3 issue ? PM27

16. 16 © ACRI-ST, all rights reserved – 2015 Same thing in Aquarius (E. Dinnat, 2014) Other validations ? Altimeters ? PM27

17. 17 © ACRI-ST, all rights reserved – 2015 To be done from reprocessing data 21/23-04-2015PM 27 Try to conclude at high latitude Systematic comparison with GPS Systematic comparison with Aquarius Other data ? Altimeters ? with IPGP ? JASON (Elvira Astafyeva, 2014)