MetOc products for maritime operations
MetOc products for maritime operations – thermal fronts, eddies and water mass boundaries with RADARSAT. Defence R&D Canada – Ottawa Contract Report CR 2007-101, 42 pp, 2007.

Abstract

Thirty-five RADARSAT images collected over eastern Canadian waters in 2006 were analyzed to determine this sensor's potential application to MetOc (meteorology and oceanography) operations. Analyses focused on blending RADARSAT, sea-surface temperature and bathymetric data as a means of detecting oceanographic features that have surface thermal signatures. Results demonstrate remarkable improvement in thermal feature detection by using latest-pixel composite sea-surface temperature products instead of the mean composite products presently used by federal maritime operations. RADARSAT consistently detected certain oceanographic features having surface thermal signatures, but not others. Conclusive explanation of this difference requires analysis of associated surface currents and atmospheric boundary conditions, however, results suggest there is a threshold in the magnitude of the surface thermal gradient associated with these frontal features, of about 0.4 to 0.5 oC/km, below which RADARSAT does not detect the feature. Although preliminary, these results suggest that under conditions of low to moderate wind speeds, the surface thermal gradient can be used as an indicator of ocean features detected by RADARSAT. Results also suggest a possible feature orientation bias in RADARSAT's ability to detect surface thermal features which stems from the sensor's directional bias in detecting the surface current gradient. RADARSAT consistently detected moderate to strong wind fronts to seaward of Georges Bank and these wind fronts co-located with thermal features attributable to either the shelf-slope front or aspects of the Gulf Stream. This observation suggests that detection of persistent wind fronts associated with certain thermal fronts, such as the northern wall of the Gulf Stream, could be used as an indicator of the thermal front itself.