CAPS-Based Particle Single Scattering Albedo Monitor

Aerosol particles affect the radiative balance of the earth directly, by scattering and absorbing solar and terrestrial radiation, and indirectly, by acting as cloud condensation nuclei. It is now recognized that the atmospheric loading of aerosols, generated through human activities, can influence the earth¿s radiation budget in an amount comparable with greenhouse gases. However, uncertainties in the current understanding of aerosol forcing, both directly and indirectly, limit the ability to quantify human influences on climate change. This project will design, construct, and test a particle-single-scattering albedo monitor that will combine extinction and scattering measurements in one instrument with rapid time-response, active temperature/relative-humidity control, and high sensitivity. In Phase I, a laboraotry prototype will be constructed and calibrated. Air flows with known concentrations of (polystyrene latex) particles, with albedos at or near one, will be flowed through the system and the total extinction and scattering coefficients measured. The particle-single-scattering albedos will be calculated as a function of particle size, in order to determine whether there is any size dependent error in the measurement. Detailed ray-tracing modeling will be performed, and a design for a field-ready prototype will be prepared. In Phase II, the prototype will be constructed, and the sensor will be deployed on various field missions. Commercial Applications and Other Benefits as described by the Applicant: The monitor should yield direct commercial sales from the atmospheric sciences and environmental pollution research and development communities. The comparatively low cost and ease of use of this sensor would allow the nearly routine measurement of the scattering properties of atmospheric aerosols, something precluded by the cost and complexity of current instrumentation