The MIAMI-2001 Radiometer Intercomparison

1. The MIAMI-2001 Radiometer Intercomparison Peter J. Minnett Rosenstiel School of Marine and Atmospheric Science, University of Miami, Florida, USA Ian J. Barton CSIRO Marine Labs Hobart, Australia Joe P. Rice Optical Technology Division National Institute of Standards and Technology Gaithersburg, Maryland, USA ENVISAT Validation Workshop Frascati, Italy 12 December 2002

2. Overview • Objectives • Radiometers • Laboratory results • Shipboard results • Conclusions

3. Miami-2001Radiometer Intercalibration Workshop. To calibrate and compare infrared radiometers used in the validation of the different surface temperature products derived from earth observation satellites. These aims included an assessment of the relative performance of each instrument as well as ensuring that surface measurements used in satellite product validation are traceable to SI standard units.

4. Participants Dr. Ali Abtahi NASA Jet Propulsion Laboratory, Pasadena, CA, USA Dr. Ian Barton CSIRO Marine Research, Hobart, Australia Dr. Jim Butler NASA GSFC, Greenbelt, MD, USA Dr. Craig Donlon EEC Joint Research Centre, Ispra, Italy Dr. Marianne Edwards Leicester University, UK Ms. Ruth Fogelberg Applied Physics Laboratory, U. Washington, Seattle, WA,USA Ms. Jenny Hanafin RSMAS-MPO, University of Miami, FL, USA Dr. Simon Hook NASA Jet Propulsion Laboratory, Pasadena, Ca., USA Dr. Andy Jessup Applied Physics Laboratory, U. Washington, Seattle, WA, USA Dr. Carol Johnson NIST, Gaithersburg, MD, USA Ms. Erica Key RSMAS-MPO, University of Miami, FL, USA Ms. Trina Lichtendorf Applied Physics Laboratory, U. Washington, Seattle, WA, USA Mr. Kevin Maillet RSMAS-MPO, University of Miami, FL, USA Dr. Peter Minnett RSMAS-MPO, University of Miami, FL, USA Dr. Tim Nightingale Rutherford Appleton Laboratory, Chilton, UK. Dr. Mike Reynolds Brookhaven National Laboratory, USA Dr. Joe Rice NIST, Gaithersburg, MD,USA Dr. Goshka Szczodrak RSMAS-MPO, University of Miami, FL, USA Dr. Brian Ward NOAA, AOML, Miami, FL, USA Dr. Gary Wick NOAA, ETL, Boulder, CO., USA

5. Instruments Infrared radiometers that participated in the campaign Black bodies used for laboratory calibration.

6. Radiometers

7. Radiometer Characteristics *The Heitronics uses a chopped pyroelectric detector. #The ISAR Heitronics is modified to allow the measurement of temperatures down to –100oC.

8. Objectives of laboratory measurements To characterize all black-body calibration targets by NIST EOS TXR, leading to an estimate of emissivity of black body cavities as a function of temperature, wavelength (5 and 10µm) and, aperture.

9. The NIST EOS TXR EOS Standard Cryogenic detectors (liquid N2) λ= 5 & 10µm See:Rice, J. P. and B. C. Johnson, 1998. The NIST EOS Thermal-Infrared Transfer Radiometer., Metrologia, 35, 505-509

10. NIST water-bath black-body calibration target See: Fowler, J. B., 1995. A third generation water bath based blackbody source., J. Res. Natl.Inst. Stand. Technol., 100, 591-599

11. CASOTS black-body calibrator See: Donlon, C. J., T. Nightingale, L. Fiedler, G. Fisher, D. Baldwin and I. S. Robinson, 1999. The Calibration and Intercalibration of Sea-Going Infrared Radiometer Systems Using a Low Cost Blackbody Cavity, Journal of Atmospheric and Oceanic Technology, 16, 1183–1197

12. Temperature plateaus

13. Black-body calibrators

14. Black – body calibration errors

15. CSIRO DAR011 at the RSMAS WB-BB target

16. Radiometer calibration errors

17. And so to sea…….

18. On the R/V F.G. Walton-Smith

19. The SST radiometers

20. The radiometers

21. Cruise track

22. Time series of measurements

23. Results of at-sea comparisons

24. Miami-2001Radiometer Intercalibration Workshop. • Following the radiometer calibration, intercomparison, and testing under field conditions, the international community has increased confidence in the results to be provided for validation of satellite-derived SSTs from the participating instruments. • Radiometers work to ~0.1K uncertainty levels in the field • Black body calibrators have been characterized with reference to NIST standard

25. Publications, in review • Rice, J. P., J. J. Butler, B. C. Johnson, P. J. Minnett, K. A. Maillet, T. J. Nightingale, S. J. Hook, A. Abtahi, C. J. Donlon and I. J. Barton. The Miami2001 Infrared Radiometer Calibration and Intercomparison: 1. Laboratory Characterization of Blackbody Targets, Journal of Atmospheric and Oceanic Technology. • Barton, I. J., P. J. Minnett, C. J. Donlon, S. J. Hook, A. T. Jessup, K. A. Maillet and T. J. Nightingale. The Miami2001 infrared radiometer calibration and inter-comparison: 2. Ship comparisons, Journal of Atmospheric and Oceanic Technology.

26. Acknowledgements Acknowledge funding from • NOAA-NESDIS • ESA • Eumetsat • Participant’s home institutes and funding agencies pminnett@rsmas.miami.edu

27. pminnett@rsmas.miami.edu