Multi-wavelength aerosol absorption spectrometer

Aerosols and clouds play a leading role in the Earth's global energy and solar radiation balance and hydrological cycle, however, the processes that govern cloud-aerosol interactions are poorly understood and represent major sources of uncertainty in predictive models. Optically absorbing aerosols (AA) contribute disproportionately and substantially to this net uncertainty in radiative forcing despite their small relative abundances compared to non-absorbing aerosol types. Improving aerosol models requires accurate and detailed information on the aerosol absorption and light scattering properties. This SBIR project will develop an innovative multiwavelength aerosol optical absorption spectrometer that will implement direct, sensitive, and continuous measurement at up to eight wavelengths simultaneously. The ultimate goal is to develop a technology that is rugged, compact, low-power, low-maintenance and affordable to allow wide-scale deployment of the proposed aerosol spectrometers over atmospheric measurement facilities. The Phase I study will focus on: (1) designing and building a laboratory prototype of the multi-wavelength aerosol optical spectrometer, (2) characterizing the instrument performance using absorbing gases, (3) testing the laboratory prototype using AA with pre-defined optical absorption properties in collaboration with University of California, Irvine (UCI); and (4) evaluating the feasibility of the proposed method and identifying the engineering challenges of transitioning the technology to a standalone, rugged, field-deployable prototype in Phase II. The successful completion of this Phase I/II program will lead to development of multiwavelength aerosol optical absorption measurement technology primarily designed for field deployment on ground-based, marine and aerial platforms. When carried over into Phase III and beyond, this project will be of great benefit to the public and the Federal Government. Extensive and accurate measurements of AA optical absorption are of critical importance for developing predictive understanding of their properties and role in Earth's radiative budget, and more reliable predictions of climate patterns.