1. The Evolving Sea Surface Temperature (SST) Record from ICOADS Scott Woodruff, NOAA/ESRL Richard W. Reynolds, NOAA/NCDC Elizabeth C. Kent, UK NOCS Steven J. Worley, NCAR “Climate Variability and Extremes During the Past 100 Years” Gwatt, Switzerland, 24-26 July 2006 Dec 1942

2. Aim Review current status and future challenges of global SST data Review current status and future challenges of global SST data Focus: in situ & 20th Century Focus: in situ & 20th Century Outline Evolution of… Evolution of… SST observing system SST observing system ICOADS (SST plus other variables) ICOADS (SST plus other variables) product development product development Future directions Future directions

3. Evolving…SST observing sys Brussels 1853 Maritime Conf. Brussels 1853 Maritime Conf. Voluntary Observing Ships Voluntary Observing Ships Buoys & other automated Ocean Data Acquisition Systems (ODAS): 1970s Buoys & other automated Ocean Data Acquisition Systems (ODAS): 1970s Joint WMO-IOC Technical CommissionJoint WMO-IOC Technical Commission Formed: 1999 Formed: 1999

4. Recent SST Adequacy: GCOS Essential Climate Variable (ECV)  Best observed ECV  Only ECV to have improved in data quality since 1980’s  Highly complex data mixture, even recently WCRP WGASF: net heat flux to 10W/m 2 per 5  box

5. Historical SST Sources [Bucket photos courtesy of David Parker, Met Office]

6. Modern SST sources Not in ICOADS - GHRSST Pilot Project: for satellite SST

7. Observing System (OS) Changes SST per 2  box per month 45% of possible 2° boxes have 5 samples/month in the 70-80’s Decreasing low counts due to reduced ships observations Increasing high counts due to high frequency sampling from buoys

8. OS changes: % at UTC obs time 6-hrly ships > buoy reports US GMN obs

9. Evolving…ICOADS International Comprehensive Ocean-Atmosphere Data Set Cooperative NOAA-NCAR project - Releases:Cooperative NOAA-NCAR project - Releases: 1: 1854-1979 (done 1985) 1: 1854-1979 (done 1985) 2.3: 1784-2005 (done 2006) 2.3: 1784-2005 (done 2006) SST plus other variables SST plus other variables Delayed-mode (DM) dataDelayed-mode (DM) data Ship & ocean profile temps. (≤ 3m): thru 1997 Ship & ocean profile temps. (≤ 3m): thru 1997 Buoys: thru 2004 Buoys: thru 2004 Real-time (GTS) only: for 2005 Real-time (GTS) only: for 2005

10. SST obs per 2  box per decade 1900-09 1920-29 1940-49 1960-69 1980-89 2000-05 R1 (1985) R2 (2002) by R2.3 (2006)

11. Platform Mix: 1936-2005 > GTS drifter reports consolidated in DM

12. VOS Metadata Blend: WMO Pub. 47 (~annual) Reports with metadata Declining VOS… [With Liz Kent & Dave Berry, UK NOCS]

13. Benefits from DM Data and Metadata: SST method indicator GTS formatLogbook formatWMO Pub. 47 intakebucketbait tanks therm. bucketcondenser intakebucket hull contact sensortrailing thermistorintake/inlet otherhull contact “through hull””through hull" radiation therm. bait tanks therm.trailing thermistor othersother (footnote) plus: sstD (depth) Potential usage in bias adjustments to help improve the long-term climate change record

14. Evolving… SST Product Development ICOADS monthly summaries (2  /1  - unanalyzed) ICOADS monthly summaries (2  /1  - unanalyzed) No bias adj. (Worley et al., Woodruff et al., 2005) No bias adj. (Worley et al., Woodruff et al., 2005) Blended satellite + in situ, e.g.: Blended satellite + in situ, e.g.: NOAA OI.v2 (Reynolds et al., 2002) (new Oct ‘06) NOAA OI.v2 (Reynolds et al., 2002) (new Oct ‘06) Historical reconstructions, e.g.: Historical reconstructions, e.g.: NOAA ERSST.v2 (Smith & Reynolds, 2004) NOAA ERSST.v2 (Smith & Reynolds, 2004) HadISST1.1, HadSST2 (Rayner et al., 2003, 2005) HadISST1.1, HadSST2 (Rayner et al., 2003, 2005) Kaplan et al. (1998), Ishii et al. (2005), etc. Kaplan et al. (1998), Ishii et al. (2005), etc.

15. SST: Dec 1942 ICOADS ERSSTHadISST

16. In situ data remain vital for bias-adjusting the satellite data (including GHRSST-PP) Nighttime Zonal Bias: AVHRR - HadSST2 AVHRR Pathfinder: Reanalysis: w/ residual problems AVHRR Operational: seasonal cycle of biases in mid latitudes 90N 90S 90N '82'05

17. Future Directions Digitization & blending of new data/metadata Improved QC and bias adjustments Availability of other ECVs in ICOADS to validate SST (e.g., AT) Improved climate-quality analyses Accelerating international SST efforts

18. Digitize & Blend New Data

19. SST Bias Example: Bucket vs. Intake SST Historical Metadata are Critical VOS: back to 1955 (blended for 1973-) ODAS metadata: fragmented/missing –New JCOMM/China meta-database

20. Recent SST Biases: Ship and Buoy Differences Buoy SST colder than ship (mixed sensors) More buoys later: increasing bias Southern Oceans: drifting buoys Tropics: + TAO OI.v2 similar to ship+buoy

21. META-T Pilot Project JCOMM Workshop to establish a Pilot Project for the collection of real-time (RT) metadata re SST and temperature profiles (March 2006, UK)JCOMM Workshop to establish a Pilot Project for the collection of real-time (RT) metadata re SST and temperature profiles (March 2006, UK) Goals:Goals: Facilitate use of ocean temp. data Facilitate use of ocean temp. data Harmonize ocean & met-ocean practices Harmonize ocean & met-ocean practices Seeking agreed formats & practices Seeking agreed formats & practices

22. Conclusions SST Observing System: high level of heterogeneity ICOADS: widely used, but declining NOAA budgets Product developments: ICOADS is critical foundation Future: More data, bias adj., climate-quality analyses International efforts: GHRSST-PP, META-T, etc. CLIMAR-III: 3rd JCOMM Workshop on Advances in Marine Climatology Planned for Early 2008

23. Links and References icoads.noaa.gov ioc.unesco.org/jcomm/ www.ghrsst-pp.org Ishii, M., A. Shouji, S. Sugimoto, and T. Matsumoto, 2005: Objective analyses of sea- surface temperature and marine meteorological variables for the 20th century using ICOADS and the Kobe Collection. Int. J. Climatol. (CLIMAR-II Special Issue), 25, 865-879 (DOI: 10.1002/joc.1169). Kaplan, A., M.A. Cane, Y. Kushnir, A.C. Clement, M.B. Blumenthal, and B. Rajagopalan, 1998: Analysis of global sea surface temperature 1856-1991. J. Geophys. Res., 103(C9), 18567-18589. Rayner, N.A., D.E. Parker, E.B. Horton, C.K. Folland, L.V. Alexander, D.P. Rowell, E.C. Kent, and A. Kaplan, 2003: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108(D14), 4407, doi:10.1029/2002JD002670. Rayner, N.A., P. Brohan, D.E. Parker, C.K. Folland, J.J. Kennedy, M. Vanicek, T.J. Ansell, and S.F.B. Tett, 2006: Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century: The HadSST2 dataset. J. Climate, 19, 446-469. Reynolds, R.W., N.A. Rayner, T.M. Smith, D.C. Stokes, and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 1609-1625. Smith, T.M., and R.W. Reynolds, 2004: Improved extended reconstruction of SST (1854- 1997). J. Climate, 17, 2466-2477. Woodruff, S.D., H.F. Diaz, S.J. Worley, R.W. Reynolds, and S.J. Lubker, 2005: Early ship observational data and ICOADS. Climatic Change, 73, 169-194. Worley, S.J., S.D. Woodruff, R.W. Reynolds, S.J. Lubker, and N. Lott, 2005: ICOADS Release 2.1 data and products. Int. J. Climatol. (CLIMAR-II Special Issue), 25, 823-842 (DOI: 10.1002/joc.1166).