HR: 0800h
AN: A21B-0841    [Abstracts]
TI: Regional-Scale Measurements of Smoke-Impacted Haze in California, Oregon and Washington
AU: * McMeeking, G R
EM: grm@lamar.colostate.edu
AF: Colorado State University, Dept. of Atmospheric Science Colorado State University, Fort Collins, CO 80523
AU: Kreidenweis, S M
EM: sonia@atmos.colostate.edu
AF: Colorado State University, Dept. of Atmospheric Science Colorado State University, Fort Collins, CO 80523
AU: Carrillo, J
EM: jackieheath@yahoo.com
AF: Colorado State University, Dept. of Atmospheric Science Colorado State University, Fort Collins, CO 80523
AU: Collett, J L
EM: collett@lamar.colostate.edu
AF: Colorado State University, Dept. of Atmospheric Science Colorado State University, Fort Collins, CO 80523
AU: Lunden, M
EM: mmlunden@lbl.gov
AF: Lawrence Berkeley National Laboratory, Atmospheric Sciences Dept. LBNL 1 Cyclotron Rd, MS 51-208, Berkeley, CA 94720
AU: Malm, W C
EM: malm@cira.colostate.edu
AF: Cooperative Institute for Research in the Atmosphere, CIRA Colorado State University, Fort Collins, CO 80523
AU: Day, D
EM: day@cira.colostate.edu
AF: Cooperative Institute for Research in the Atmosphere, CIRA Colorado State University, Fort Collins, CO 80523
AB: Aerosol particles can degrade visibility and affect direct radiative forcing because they can scatter and absorb light. The magnitude of these effects depends on their physical, chemical and optical properties. Observations of these properties made in 38 locations in Washington, Oregon and California show a strong and regional-scale influence of wildfire smoke during the summer of 2002. Aerosol measurements made during an intensive field campaign conducted in July, August and September 2002 in Yosemite National Park suggested that smoke-impacted aerosols were present at the park during frequent haze episodes. During these episodes particles measured in Yosemite increased in size (volume mean diameters approaching 400 nm) and had higher mass scattering efficiencies (6 m² g^-1) compared to other times. Examination of backward trajectories showed that meteorological conditions during the Yosemite study were dominated by transport from western and southern Oregon, a region which saw a high amount of fire activity during the summer of 2002. We compare Yosemite observations to aerosol data in California, Oregon and Washington from the IMPROVE aerosol monitoring network, sun photometer data from the San Joaquin Valley of California and aerosol measurements conducted at a remote Sierra Nevada monitoring site located just west of Lake Tahoe. Observations of aerosol properties such as size distributions, scattering coefficients, carbon composition and ultra-violet light absorption at these sites tracked closely to other measurement sites, including Yosemite. This behavior suggests that the measurement locations were affected by several regional-scale smoke-impacted events.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005