High-resolution airborne infrared measurements of ocean skin temperature

Airborne measurements of ocean skin temperature T/sub s/ are presented from the Coupled Boundary Layers, Air-Sea Transfer in Low Winds (CBLAST-Low) Pilot Experiment in August 2001 off Martha's Vineyard, MA. We used an infrared (IR) camera with a spatial resolution of 1 m or less and temperature resolution of roughly 0.02/spl deg/C. Using subframe sampling of the IR imagery, we achieve lower noise and higher spatial resolution than reported by previous investigators using IR radiometers. Fine-scale maps of T/sub s/ exhibit horizontal variability over spatial scales ranging from O(10 km) down to O(1 m) that are related to atmospheric and subsurface phenomena under low to moderate wind conditions. Based on supporting measurements of wind and waves, we identify coherent ramp-like structures in T/sub s/ with stratification breakdown and meandering streaky features with internal waves. Regional maps of T/sub s/ show the standard deviation for the region is /spl plusmn/1.04/spl deg/C, while the meridional and zonal variability is 0.23/spl deg/C /spl middot/ km/sup -1/ and 0.27/spl deg/C /spl middot/ km/sup -1/, respectively. This temperature variability results in meridional and zonal scalar heat flux variability of 7.0 W /spl middot/ m/sup -2/ /spl middot/ km/sup -1/ and 7.6 W /spl middot/ m/sup -2/ /spl middot/ km/sup -1/, respectively. Our results demonstrate the potential for airborne IR imagery accompanied by high-quality ocean data to identify T/sub s/ features produced by subsurface circulation.

[1]  E. F. Bradley,et al.  Bulk parameterization of air‐sea fluxes for Tropical Ocean‐Global Atmosphere Coupled‐Ocean Atmosphere Response Experiment , 1996 .

[2]  Timothy L. Crawford,et al.  Spatial and temporal variability of heat, water vapor, carbon dioxide, and momentum air-sea exchange in a coastal environment , 1993 .

[3]  Godfrey L. Smith,et al.  Infrared imagery of ocean internal waves , 2004 .

[4]  E. F. Bradley,et al.  Cool‐skin and warm‐layer effects on sea surface temperature , 1996 .

[5]  Edward J. Walsh,et al.  Aircraft observations of sea surface temperature variability in the tropical Pacific , 1997 .

[6]  J. Klymak,et al.  Internal solitary waves of elevation advancing on a shoaling shelf , 2003 .

[7]  R. Kropfli,et al.  Relationships between strong internal waves in the coastal zone and their radar and radiometric signatures , 1999 .

[8]  Christopher W. Fairall,et al.  Direct Covariance Flux Estimates from Mobile Platforms at Sea , 1998 .

[9]  R. Weller,et al.  Observations of internal bores and waves of elevation on the New England inner continental shelf during summer 2001 , 2005 .

[10]  C. Fairall,et al.  Coupling of internal waves on the main thermocline to the diurnal surface layer and sea surface temperature during the Tropical Ocean‐Global Atmosphere Coupled Ocean‐Atmosphere Response Experiment , 1998 .

[11]  W. Mcleish,et al.  On the mechanisms of wind-slick generation , 1968 .

[12]  A. Soloviev.  Coherent structures at the ocean surface in convectively unstable conditions , 1990, Nature.

[13]  W. Mcleish.  Spatial spectra of ocean surface temperature , 1970 .

[14]  M. Osborne.  The effect of convergent and divergent flow patterns on infrared and optical radiation from the sea , 1965 .

[15]  Rodney D. Peltzer,et al.  A remote sensing study of a surface ship wake , 1987, OCEANS '85 - Ocean Engineering and the Environment.

[16]  K. Katsaros.  Radiative Sensing of Sea Surface Temperature , 1980 .