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me Valida&on of IASI spectral radiances using aircra6 underflight data collected during JAIVEx David Tobin, Hank Revercomb, Fred Best, Joe Taylor, Steve Dutcher, Bob Knuteson, William Smith Space Science and Engineering Center, University of Wisconsin‐Madison, USA CART‐site MetOp‐ Night MetOp & Aqua Gulf‐ Night CART‐site MetOp Day MetOp & Aqua Day Gulf ‐ Day MetOp & Aqua CART Site Day MetOp & Aqua Gulf ‐ Day MetOp & Aqua Night CART site Other JAIVEx Cal/Val Flights: Four SGP CART‐site (2 day & 2 night); Three Gulf of Mexico (2 day & 1 night); Five joint MetOp & Aqua (3 day & 2 night) IASI, NAST‐I, SHIS Mean spectra wavenumber 0.09 K 0.16 K NAST‐I S‐HIS 0.07 K 0.12 K IASI Shortwave Valida&on IASI minus NAST‐I, IASI minus SHIS Double obs‐calc method IASI, NAST‐I, SHIS Mean spectra wavenumber BT (K) Diff (K) IASI minus NAST‐I, IASI minus SHIS 0.00 K 0.02 K NAST‐I: S‐HIS: 0.08 K 0.12 K 0.03 K 0.00 K 0.16 K 0.14 K IASI Longwave Valida&on 19 April 2007 Double obs‐calc method IASI, NAST‐I, SHIS Mean spectra wavenumber 0.12 K 0.20 K NAST‐I: S‐HIS: 0.04 K 0.03 K ‐0.19 K ‐0.08 K IASI Midwave Valida&on IASI minus NAST‐I, IASI minus SHIS Double obs‐calc method Flight over ARM SGP site, 19 April 07 290 285 280 IASI 900 cm ‐1 BT(K) ARM site + S‐HIS FOVs o NAST‐I FOVs Imager Data Summary Direct airborne validaWon of radiances from the new IASI interferometer sounder on Metop was successfully performed during the Joint Airborne IASI ValidaWon Experiment (JAIVEx) conducted 14 April ‐ 4 May 2007. The experiment included the NASA WB57 aircra] carrying the UW Scanning HIS, the LaRC NAST‐ I, and the MIT/LL NAST‐Microwave, flown in coordinaWon with the Facility for Airborne Atmospheric Measurements BAe146‐301 carrying the ARIES interferometer plus a wide range of in situ instrumentaWon and dropsondes. This poster focuses on validaWon of IASI spectral radiances using the high alWtude aircra] observaWons and a double observed minus calculated analysis technique. Conclusions • JAIVEx underflight evaluaWons of IASI show agreement with the aircra] observaWons on the order of 0.1K or less. • The absolute calibraWon of IASI and AIRS Radiance are comparable and represent a huge improvement over past IR sounders for both weather and climate applicaWons • The value of aircra] observaWons for direct radiance validaWon has now been definiWvely proven (0.1 K sensiWvity) • ValidaWon over the mission lifeWmes is sWll needed to assure the long‐term stability IASI, NAST‐I, and SHIS Mean Spectra (IASI L1C and NASTI spectra processed to match SHIS spectral resoluWon) 19 April 2007 wavenumber BT (K) chamber AERI blackbody Plan: perform periodic end‐to‐end laboratory radiance evalua&ons under flight‐like condiWons with NIST transfer sensors such that satellite validaWon analyses are traceable to the NIST radiance scale. TXR Ch1 TXR Ch2 Scanning‐HIS spectra NIST TXR S‐HIS AERI BB NIST TXR tests of Scanning HIS Radiance Calibra&on & AERI Blackbody Radiance Knowledge • mean agreement between TXR and S‐HIS of ~30 mK, well less than conservaWve esWmates of the S‐HIS propagated 3‐sigma absolute radiance uncertainWes • TXR uncertainty is ~0.2 K • larger mean diffs (~0.15K) in Ch1 (5μm) under invesWgaWon AERI minus TXR AERI minus S‐HIS TXR operaWons and data c/o Joe Rice and Joe O’Connel UW‐SSEC/NIST 10 μm results from January 2007 BT (K) BT Diff (K)
