The Evolving Sea Surface The Evolving Sea Surface Temperature (SST) Temperature (SST)
Record from ICOADSRecord from ICOADSScott Woodruff, NOAA/ESRL
Richard W. Reynolds, NOAA/NCDCElizabeth C. Kent, UK NOCS
Steven J. Worley, NCAR
“Climate Variability and ExtremesDuring the Past 100 Years”
Gwatt, Switzerland, 24-26 July 2006
Dec 1942
AimAim• Review current status and future Review current status and future
challenges of global SST datachallenges of global SST data Focus: Focus: in situ & in situ & 20th Century20th Century
Outline• Evolution of…Evolution of…
SST observing systemSST observing system
ICOADS (SST plus other variables)ICOADS (SST plus other variables)
product developmentproduct development
• Future directionsFuture directions
Evolving…SSTEvolving…SSTobserving sysobserving sys
• Brussels 1853 Maritime Conf.Brussels 1853 Maritime Conf.
Voluntary Observing ShipsVoluntary Observing Ships
• Buoys & other automated Ocean Data Buoys & other automated Ocean Data Acquisition Systems (ODAS): 1970sAcquisition Systems (ODAS): 1970s
• Joint WMO-IOC Technical CommissionJoint WMO-IOC Technical Commission Formed: 1999Formed: 1999
Recent SST Adequacy:Recent SST Adequacy:GCOS Essential Climate Variable (ECV)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/m2 per 5 box
Historical SST SourcesHistorical SST Sources
[Bucket photos courtesy of David Parker, Met Office]
Modern SST sourcesModern SST sources
Not in ICOADS - GHRSST Pilot Project: for satellite SST
Observing System (OS) ChangesObserving System (OS) ChangesSST per 2SST per 2 box per month 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
OS changes: % at UTC obs timeOS changes: % at UTC obs time
6-hrly ships
> buoy reports
US GMN obs
Evolving…ICOADSEvolving…ICOADSInternationalInternational Comprehensive Ocean-Atmosphere Data Set 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 variablesSST plus other variables
• Delayed-mode (DM) dataDelayed-mode (DM) data
Ship & ocean profile temps. (≤ 3m): thru 1997Ship & ocean profile temps. (≤ 3m): thru 1997
Buoys: thru 2004Buoys: thru 2004
• Real-time (GTS) only: for 2005Real-time (GTS) only: for 2005
SST obs SST obs per 2per 2 box box
per per decadedecade
1900-09
1920-29
1940-49
1960-69
1980-89
2000-05 R1 (1985)
R2 (2002)
by R2.3 (2006)
Platform Mix: 1936-2005Platform Mix: 1936-2005
> GTS drifter reports consolidated in DM
VOS Metadata Blend:VOS Metadata Blend:WMO Pub. 47 (~annual)WMO Pub. 47 (~annual)
Reports with metadata
Declining VOS…
[With Liz Kent & Dave Berry, UK NOCS][With Liz Kent & Dave Berry, UK NOCS]
Benefits from DM Data and Metadata:Benefits from DM Data and Metadata:SST method indicatorSST method indicator
GTS format Logbook format WMO Pub. 47intake bucket bait tanks therm.
bucket condenser intake bucket
hull contact sensor trailing thermistor intake/inlet
other hull contact hull contact
“through hull” ”through hull"
radiation therm. radiation therm.
bait tanks therm. trailing thermistor
others other (footnote)
plus: sstD (depth)
Potential usage in bias adjustments to help improve the long-term climate change record
Evolving…Evolving…SST Product DevelopmentSST Product Development
• ICOADS monthly summaries (2ICOADS monthly summaries (2/1/1 - unanalyzed) - 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.
SST: Dec 1942SST: Dec 1942ICOADS
ERSSTHadISST
In situ data remain vital for bias-adjusting the satellite data (including GHRSST-PP)
Nighttime Zonal Bias: AVHRR - HadSST2Nighttime Zonal Bias: AVHRR - HadSST2
AVHRRPathfinder:
Reanalysis:w/ residual
problems
AVHRROperational:
seasonal cycle of biases in mid
latitudes
90N
90S
90S
90N'82 '05
Future DirectionsFuture 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
Digitize & Blend New DataDigitize & Blend New Data
SST Bias Example:SST Bias Example:Bucket vs. Intake SSTBucket vs. Intake SST
Historical Metadata are CriticalHistorical Metadata are Critical• VOS: back to 1955 (blended for 1973-)• ODAS metadata: fragmented/missing
– New JCOMM/China meta-database
Recent SST Recent SST Biases: Ship and Biases: Ship and Buoy DifferencesBuoy 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
META-T Pilot ProjectMETA-T Pilot Project• JCOMM Workshop to establish a Pilot JCOMM Workshop to establish a Pilot
Project for the collection of real-time Project for the collection of real-time (RT) metadata re SST and temperature (RT) metadata re SST and temperature profiles (March 2006, UK)profiles (March 2006, UK)
• Goals:Goals: Facilitate use of ocean temp. dataFacilitate use of ocean temp. data
Harmonize ocean & met-ocean practicesHarmonize ocean & met-ocean practices
Seeking agreed formats & practicesSeeking agreed formats & practices
ConclusionsSST Observing System: high level of heterogeneityICOADS: widely used, but declining NOAA budgetsProduct developments: ICOADS is critical foundationFuture: More data, bias adj., climate-quality analysesInternational efforts: GHRSST-PP, META-T, etc.
CLIMAR-III: 3rd JCOMM Workshop on Advances in Marine ClimatologyPlanned for Early 2008
Links and ReferencesLinks and Referencesicoads.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).