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).