Use of Spaceborne Synthetic Aperture Radar Imagery of the Sea Surface in Detecting the Presence and Structure of the Convective Marine Atmospheric Boundary Layer

Abstract

Two distinct backscatter regimes are seen on a European remote sensing satellite ERS-1 C-band (5.6 cm) synthetic aperture radar (SAR) image of the sea surface during a time of fair synoptic-scale weather conditions. One backscatter regime is mottled. In contrast to that, the second backscatter regime is marbled. The authors hypothesize that the mottled backscatter pattern is a characteristic SAR backscatter pattern linked to the presence of the convective (i.e., statically unstable/convective-eddy containing) marine atmospheric boundary layer (CMABL) and can be used to help determine CMABL structure [convective-eddy type (cellular convection versus longitudinal rolls), eddy wavelength, and CMABL depth (via mixed-layer similarity theory for aspect ratio)]. The hypothesis linking the presence and structure of the CMABL to the mottled backscatter pattern on SAR imagery is validated by analyzing data from a number of sources gathered in the vicinity of the boundary between the mottled and marbled regimes on the SAR image.