Argo Errors and Estimating Heat Content and Argo Errors

1. Argo Errors and Estimating Heat Content and Argo Errors Argo Errors and Estimating Heat Content and Argo Errors Josh K. Willis joshua.k.willis@jpl.nasa.gov Jet Propulsion Laboratory

2. Overview • Ocean “cooling” – a rude awakening to depth errors • Argo and altimeter data as calibration tools • Time evolution of recent XBT biases • Remaining errors

3. The Problem

4. Cooling!!! 2003 to 2005 cooling: -1.0 ± 0.33 W/m2 (Averaged over Earth’s surface) Upper-Ocean “cooling” from Lyman et al. (GRL, 2006)

5. My brush with Rush

6. Previous In Situ Data biases SOLO/FSI floats have a cold bias at depth

7. “To overturn the world economy based on the musings of a few idiot leftist scientists is just stupid, and that’s what Global Warming is all about.” ̶ Rush

8. WHOI float distribution

9. WHOI float biases

10. A correction to “recent cooling” Ocean Heat Content from 2004 to 2006 Removing the bad float data reduces the cooling but does not completely eliminate it. From Willis et al., GRL, in prep.

11. XBT data is biased warm Shallow XBTs have a bigger bias from Wijffels et al., accepted.

12. A correction to “recent cooling” Ocean Heat Content from 2004 to 2006 Another bias: XBTs are biased warm, which also causes spurious cooling. From Willis et al., GRL, in prep.

13. Isotherm Displacement: Dz = Tclim – T dTclim /dz XBT bias & fall-rate errors – pair analysis Comparison of Isotherm Displacements XBT/Argo pairs ~12,000 Argo/CTD pairs ~2,000 From Willis et al., GRL, in prep.

14. Climatologies with XBT data bias warm Levitus, WOA05 climatology Gouretski & Koltermann, WGHC climatology

15. A Technique

16. The “pseudo pair” Correlation oefficient, r between SSH anomaly and T(400 m) • Much of upper ocean T variaibility is contained in SSH anomaly • Use AVISO SSH maps to make “pseudo” temperature anomalies: • Tpseudo = a(z) * SSHA From Wijffels et al., manuscript in prep.

17. “Pseudo-pair” comparison Comparison of Sippican Deep Blue probes with nearby Argo pairs (2004 – 2006), ~12,000 • Pseudo-pairs give same bias, but have narrower distribution • More comprehensive means of test XBT bias because of SSH data availability From Wijffels et al., manuscript in prep.

18. “Pseudo-pair” analysis of other data(a.k.a. sanity check) Argo profile data CTD data • CTD data show no significant bias during any time period • Argo floats show little bias except for WHOI/FSI floats From Wijffels et al., accepted

19. Other consistency checks Pseudo profiles minus real float profiles for 3000 floats Detecting corrections

20. Corrections

21. In the 1990’s altimeter allows correction by probe type Time dependence of bias in Sippican Deep Blue XBT probes • Bias increases over time • Hi bias in later years may reflect “double” application of Hanawa et al. (1995) correction From Wijffels et al., manuscript in prep.

22. Stretching factor by probe type

23. Revised ocean heat content estimate

24. Remaining problems

25. Skewness: significant difference between mean and median Wire stretch or QC issue? Remaining Errors

26. Remaining Errors Gaussian Tail for positive depth error is much bigger

27. Re-checking repaired float data WHOI FSI floats WHOI SBE floats Non-WHOI, N. Atl. • Downloaded after March 1, 2008 • 11 FSI/uncorrectable floats, 260 profiles • About 3000 profiles, FSI/correctable in North Atlantic • Red 10 independent groups of 3000 non-FSI floats in N. Atlantic • WHOI/SBE • 2700 sbe pmin=5 • 2100 sbe pmin=6 Non-WHOI, N. Atl. FSI/uncorrected SBE Pmin=6 SBE Pmin=5 FSI/uncorrected

28. Other stuff

29. addition of heat addition of freshwater What causes globally-averagedsea level rise? Total sea level rise + = (roughly) Argo GRACE Jason

30. The recent sea level budget Global Mean Sea Level Global MSL, no seasonal Total (Jason) Total (Jason) Steric (Argo) Steric (Argo) Mass (GRACE) Mass (GRACE)

31. Argo profiles, displacements and altimetry 2004 – 2006 mean SSH Absolute geostrophic velocity from 0 to 2000 db at 37°N • Altimeter is used to reduce eddy variability in bothtypes of Argo data • Integrating from 0 to 1000 m and from east to west may provide estimate of AMOC transport

32. The recent sea level budget Northward transport in upper 1000 m v. latitude Transport at 45°N by temperature classes • Assume mass is closed below 2000 db. • Time averaged meridional heat transport at 45N is 0.64 ± 0.09 pW between