Application of in situ Observations to Current Satellite-Derived Sea Surface Temperature Products Gary A. Wick NOAA Earth System Research Laboratory With thanks to S. L. Castro, CCAR, University of Colorado, and D. L. Jackson, CIRES

NOAA Earth System Research Laboratory Gary A. Wick Observed Differences Between Infrared and Microwave Products Detailed comparisons between infrared and microwave SST products show complex spatial and temporal differences.

NOAA Earth System Research Laboratory Gary A. Wick In Situ Observations Moored buoys –Better calibration –Ancillary data Drifting buoys –Poorer calibration –Best spatial sampling Ship-based subsurface measurements –Concerns with intake heating Ship-based radiometer measurements –Most directly related to satellite observations –Not available in sufficient numbers until recently

NOAA Earth System Research Laboratory Gary A. Wick Historical Applications Operational SST algorithms and products –Algorithms derived from regression of satellite brightness temperatures directly against in situ observations Minimizes uncertainty related to atmospheric transmission and surface processes < 0.1 K Bias; ~0.5 K rms –Independent set of buoys retained for validation Reynolds SST analysis –Optimal interpolation of satellite and in situ observations –In situ observations used to remove bias from satellite data

NOAA Earth System Research Laboratory Gary A. Wick Ongoing Activities GODAE High Resolution Sea Surface Temperature Pilot Project National Ocean Partnership Program –Partnered with NESDIS, NRL, Universities, Remote Sensing Systems

NOAA Earth System Research Laboratory Gary A. Wick Error Characterization Approach Construct collocations between buoy measurements and satellite retrievals Bin satellite – in situ SST differences as functions of multiple environmental parameters Identify dominant dependencies Express bias and rms estimates through multi-dimensional look-up tables Parameter combinations evaluated through reduction in sensor-buoy and sensor-sensor differences

NOAA Earth System Research Laboratory Gary A. Wick Data Sources Infrared Satellite Data –AVHRR Operational NLSST - Naval Oceanographic Office Microwave Satellite Data –AMSR-E –TRMM Microwave Imager (TMI) Remote Sensing Systems – Wentz and Gentemann Buoys –QC’d GTS buoys via NCEP/CDC

NOAA Earth System Research Laboratory Gary A. Wick AVHRR Uncertainty Sources

NOAA Earth System Research Laboratory Gary A. Wick AVHRR Uncertainty Sources

NOAA Earth System Research Laboratory Gary A. Wick Microwave Uncertainty Sources

NOAA Earth System Research Laboratory Gary A. Wick Microwave Uncertainty Sources

NOAA Earth System Research Laboratory Gary A. Wick Sample Bias Adjustments

NOAA Earth System Research Laboratory Gary A. Wick Formulation Evaluation Applied derived bias adjustments to satellite observations Computed change in standard deviation of the satellite – buoy differences Done for both dependent (reanalysis) and independent (operational) periods Evaluates bias only

NOAA Earth System Research Laboratory Gary A. Wick Evaluation of Bias Adjustments Terms Net STD Reduction (%) STD Reduction for Points Adjusted (%) Points Adjusted (%) WS, WV, SST WS, SST WS, WV, SST, Ts-Ta WS, Ts-Ta, SST AMSR-E Independent Validation, Oct-Dec, 2003

NOAA Earth System Research Laboratory Gary A. Wick Impact of the Bias Adjustments Before Adjustment After Adjustment

16 Ingestion, Dissemination and Processing Service (IDPS) Global Data Analysis Centre (GDAC) SST data products (L2P, L4) Regional Data Assembly Centres (RDAC) RDAC HR-DDS archive Product Rolling Archive Metadata repository (MMR) Matchup database (MDB) USA EU Global coverage L4 SST products Global L4 analysis systems… GHRSST-PP Long Term Stewardship and Reanalysis Facility (LTSRF) at NODC Historical time series SST CDR products GHRSST Regional/Global Task Sharing A working demonstration of GEOSS!

NOAA Earth System Research Laboratory Gary A. Wick GHRSST Use of In Situ Data Buoy observations adopted as source of accuracy estimates for all satellite sensors Real-time matchup database maintained for all sensors Bias and rms estimates updated weekly based on database Efforts to withhold in situ observations from analyses to retain independence

NOAA Earth System Research Laboratory Gary A. Wick Prototype Radiometric Skin Observing System NOPP project to demonstrate the feasibility and assess the impact of routine radiometric observations of the skin temperature Multiple radiometers on ships-of-opportunity over a 3- year period –M-AERI on Royal Caribbean Explorer of the Seas –CIRIMS on Research Vessels Ron Brown and Thompson –ISAR on ferry and merchant vessel P. Minnett A. Jessup W. Wimmer

NOAA Earth System Research Laboratory Gary A. Wick Impact on Satellite Algorithms Derived simultaneous skin and subsurface SST regression algorithms from coincident observations Evaluated accuracy with independent observations Accuracy generally better for subsurface SST retrievals –Likely related to greater variability of skin observations Final results still being analyzed CIRIMS matchups M-AERI matchups 2004

NOAA Earth System Research Laboratory Gary A. Wick Ongoing Issues Independent observations Sufficient accuracy Adequate sampling of all representative environmental conditions

NOAA Earth System Research Laboratory Gary A. Wick Optimal Characterization Infrared –Satellite zenith angle –Channel 4-5 brightness temperature difference –Sea surface temperature –Climatological anomaly Microwave –Wind speed –Water vapor content –SST –Climatological anomaly