SGER: Photoacoustic Measurement of Aerosol Light Absorption for the Coastal Stratocumulus Imposed Perturbation Experiment

Nevada System Of Higher Education, Desert Research Institute, Reno NV

Investigators

Abstract

This Small Grants for Exploratory Research (SGER) project involves direct measurements aloft of aerosol light absorption in the visible range (678 nm) using a novel photoacoustic (PA) instrument during the Coastal STRatocumulus Imposed Perturbation Experiment (C-STRIPE). Airborne measurements for C-STRIPE will be made from the Office of Naval Research Center for Interdisciplinary Remotely-Piloted Aircraft Studies (ONR/CIRPAS) Twin Otter research aircraft over three weeks in July 2003 off the coast of Monterey, California. Flights will also be performed over the heavily polluted San Joaquin Valley, California continental area to examine black carbon emanating from smoke and urban/industrial plumes. By addition of this new capability to the C-STRIPE airborne instrument suite the P.I. will provide a unique qualitative measurement of aerosol light absorption aloft to assess aerosol-cloud interactions in terms of radiative forcing and cloud dynamics. An important airborne intercomparison experiment will also be conducted between this PA instrument and two other distinct techniques for measuring ambient atmospheric light absorption due to aerosols. Results from this study should increase understanding of climate forcing by aerosol impacts on radiative forcing in haze and/or cloud layers - major uncertainties currently limiting the representativeness of global climate models.