Tropical water vapor correction for remotely sensed sea surface temperature: Results using narrowband window radiance profiles from TOGA COARE

• Published in: Journal of Geophysical Research 2001-06, Vol.106 (C6), p.11423-11436
• Main Authors: Hagan, Denise E., Nalli, Nicholas R.
• Format: Article
• Language: English
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; Geophysics. Techniques, methods, instrumentation and models; Marine; Other topics; Physics of the oceans
• ISSN: 0148-0227; 2169-9275; 2156-2202; 2169-9291
• DOI: 10.1029/1999JC000143

This paper describes sea surface skin temperatures (SST) derived from unique aircraft‐based measurements and a physical multispectral retrieval technique. The aircraft data were acquired under moist atmospheric conditions over the western and eastern tropical Pacific Ocean during the Tropical Ocean‐Global Atmosphere Coupled Ocean‐Atmosphere Response Experiment and the Central Equatorial Pacific Experiment. Radiometric profiles were obtained in four contiguous channels over the spectral window region 800–1000 cm−1 during aircraft ascents from 0.03 through 4.6 km altitude. These bands subdivide the “split window” of present satellite radiometers used for measurements of SST. The use of four channels in the measurement approach was motivated by theoretical studies that suggest the need for three independent pieces of information to separate atmospheric and surface components of upwelling radiance in moist atmospheres. The analyses were unusual in that the absorption path length differed for each multispectral set of nadir observations made at discrete altitudes. The mean accuracy for retrievals at all altitudes was ≲1 K and was relatively insensitive to the guess profiles used for the simple forward radiance model. Simulated four‐channel retrievals demonstrate an rms accuracy of ≃0.3 K with negligible bias for global maritime profile conditions, which include extreme moisture‐laden samples. The results demonstrate that the combination of high‐precision measurements with a robust retrieval method can provide SST (instantaneous, global, day, or night) that meet the World Climate Research Programme accuracy objectives.