Ocean surface imprints of atmospheric boundary layer phenomena
on spaceborne synthetic aperture radar images

Xiaofeng Li



At the bottom of the marine atmospheric boundary layer (MABL), the coastal wind velocity fluctuation associated with mesoscale MABL phenomena modulates the sea surface roughness allowing imaging of these phenomena by synthetic aperture radar (SAR) through the resonant Bragg scattering mechanism. Examples of SAR observations of MABL phenomena include atmospheric lee waves, atmospheric disturbances, gravity waves, atmospheric boundary layer rolls and atmospheric fronts, katabatic winds, mesoscale phenomena such as polar mesoscale cyclones, storms, and hurricanes, island wakes, cold air outbreaks, and atmospheric vortex streets. These features usually appear as organized patterns on the spaceborne SAR images, with a swath of 500 km and spatial resolution of 100 m.

Since 1997, NOAA has sponsored a multi-year demonstration of the production and use of SAR quantitative and qualitative products in a pre-operational environment in the Gulf of Alaska and Bering Sea region, which is called the Alaska SAR Demonstration (AKDEMO) project. During this project, SAR images from Canadian RADARSAT-1 satellite have been acquired at NOAA and sea surface wind and vessels position products are derived on a daily basis. In addition, several MABL phenomena are identified on SAR images. This presentation will present an overview of the SAR observations of the MABL phenomena during the AKDEMO project and the application of fluid dynamical theories to explain these different phenomena.