HR: 0800h
AN: A31B-0828    [Abstracts]
TI: Springtime Aerosol Indirect Forcing Across the North Pacific Ocean in Observations and Global Models
AU: * Wilcox, E M
EM: eric.m.wilcox@nasa.gov
AF: Climate and Radiation Branch NASA/Goddard Space Flight Center, Code 613.2, Greenbelt, MD 20771 United States
AB: Transport of Asian aerosols across the North Pacific Ocean peaks during the spring season. A mix of aerosols is found in the maritime environment as far west as the North American West Coast, including Asian dust and pollution, local N. American pollution, and new particle formation. Aerosol transport events are arranged in plumes, with pristine maritime conditions prevailing between the plumes. Also present are complex cloud systems comprising stratocumulus decks, mixed phase cumulus, and mesoscale cyclones. The impact of Asian aerosols on cloud microphysical and radiative properties across the North Pacific Ocean basin during April 2004 is observed in aircraft and satellite observations. In-situ observations from the Cloud Indirect Forcing Experiment (CIFEX) document the decrease in cloud drop size and increase in cloud drop number concentration owing to the enhanced concentration of cloud condensation nuclei offshore of Northern California during aerosol transport events. The impact of these microphysical effects on shortwave cloud radiative forcing is quantified using blended MODIS and CERES satellite observations in the CIFEX region and across the entire ocean basin. The magnitude of the microphysical and radiative effects observed by aircraft and satellite are compared with the NOAA/GFDL AM2 and NASA GEOS global atmospheric climate models employing new physically-based parameterizations of aerosol nucleation. The ability of these models to provide quantitative estimates of aerosol indirect forcing over ocean basins is evaluated.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0321 Cloud/radiation interaction
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005