HR: 0800h
AN: A31B-0311    [Abstracts]
TI: NIST TXR Validation of S-HIS radiances and a UW-SSEC Blackbody
AU: * Taylor, J K
EM: joe.taylor@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: O'Connell, J
EM: joconnel@nist.gov
AF: National Institute of Standards and Technology (NIST), 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899, United States
AU: Rice, J P
EM: jrice@nist.gov
AF: National Institute of Standards and Technology (NIST), 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899, United States
AU: Revercomb, H E
EM: hank.revercomb@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Best, F A
EM: Fred.Best@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Tobin, D C
EM: davet@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Knuteson, R O
EM: BobK@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Adler, D P
EM: doug.adler@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Ciganovich, N C
EM: nick.ciganovich@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Dutcher, S T
EM: steved@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: LaPorte, D D
EM: dandl805@gmail.com
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Ellington, S D
EM: scott.ellington@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Werner, M W
EM: mark.werner@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AU: Garcia, R K
EM: rayg@ssec.wisc.edu
AF: Space Science and Engineering Center, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, United States
AB: The ability to accurately validate infrared spectral radiances measured from space by direct comparison with airborne spectrometer radiances was first demonstrated using the Scanning High-resolution Interferometer Sounder (S-HIS) aircraft instrument flown under the AIRS on the NASA Aqua spacecraft in 2002 with subsequent successful comparisons in 2004 and 2006. The comparisons span a range of conditions, including arctic and tropical atmospheres, daytime and nighttime, and ocean and land surfaces. Similar comprehensive and successful comparisons have also been conducted with S-HIS for the MODIS sensors, the Tropospheric Emission Spectrometer (TES), and most recently the MetOp Infrared Atmospheric Sounding Interferometer (IASI). These comparisons are part of a larger picture that already shows great progress toward transforming our ability to make, and verify, highly accurate spectral radiance observations from space. A key challenge, especially for climate, is to carefully define the absolute accuracy of satellite radiances. Our vision of the near-term future of spectrally resolved infrared radiance observation includes a new space-borne mission that provides benchmark observations of the emission spectrum for climate. This concept, referred to as the CLimate Absolute Radiance and REfractivity Observatory (CLARREO) in the recent NRC Decadal Survey provides more complete spectral and time-of-day coverage and would fly basic physical standards to eliminate the need to assume on-board reference stability. Therefore, the spectral radiances from this mission will also serve as benchmarks to propagate a highly accurate calibration to other space-borne IR instruments. For the current approach of calibrating infrared flight sensors, in which thermal vacuum tests are conducted before launch and stability is assumed after launch, in-flight calibration validation is essential for highly accurate applications. At present, airborne observations provide the only source of direct radiance validation with resulting traceable uncertainties approaching the level required for remote sensing and climate applications (0.1 K 3- sigma). For the calibration validation process to be accurate, repeatable, and meaningful, the reference instrument must be extremely well characterized and understood, carefully maintained, and accurately calibrated, with the calibration accuracy of the reference instrument tied to absolute standards. Tests of the S-HIS absolute calibration have been conducted using the NIST transfer radiometer (TXR). The TXR provides a more direct connection to the Blackbody reference sources maintained by NIST than the normal traceability of blackbody temperature scales and paint emissivity measurements. Two basic tests were conducted: (1) comparison of radiances measured by the S-HIS to those from the TXR, and (2) measuring the reflectivity of a UW-SSEC blackbody by using the TXR as a stable detector. Preliminary results from both tests are very promising for confirming and refining the expected absolute accuracy of the S-HIS.
DE: 1640 Remote sensing (1855)
DE: 1694 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting