Science Research Laboratory, Inc. (SRL) will develop a prototype Extinction Imager (EI) suitable for shipboard installation based on the research of Janet Shields (Scripps, UCSD). The Shields EI uses radiance contrast measurements of the sky/ocean interface at the horizon to determine the aerosol extinction coefficient along a horizontal path. This measurement is combined with models of atmospheric extinction as a function of altitude and vertical backscatter measurements from a ceilometer to predict extinction along arbitrary slant paths. In Phase I SRL will test an EI prototype on nominal 5 km east coast ocean ranges (1) under daylight and starlight conditions, (2) in the visible and 1000 nm wavelength bands and (3) with both black light trap targets and clear horizon measurements. These measurements will be used to design a Phase II EI camera system capable of 24/7 extinction predictions. SRL will also test MEMS Inertial Measurement Units to develop a design for an image-stabilized EI system that will scan the horizon while correcting for low-frequency pitch and roll. In Phase II the SRL EI system will be tested with a COTS ceilometer and an aethalometer to measure both aerosol and atmospheric scattering and absorption.
