HR: 09:30h
AN: A21H-06    [Abstracts]
TI: Coupled Climate Model Simulations to Bracket the Impacts of Increasing Asian Aerosols Emissions and Aggressive Future Clean Air Policies
AU: * Dubey, M K
EM: dubey@lanl.gov
AF: Los Alamos National Laboratory, D462, Los Alamos, NM 87545, United States
AU: Zhang, Y
EM: yongxin@lanl.gov
AF: Los Alamos National Laboratory, D462, Los Alamos, NM 87545, United States
AU: Sun, S
EM: ssun@giss.nasa.gov
AF: NASA GISS, 2880 Broadway, New York, NY 10025, United States
AU: Olsen, S
AF: Los Alamos National Laboratory, D462, Los Alamos, NM 87545, United States
AU: Dean, S
AF: Los Alamos National Laboratory, D462, Los Alamos, NM 87545, United States
AU: Bleck, R
AF: Los Alamos National Laboratory, D462, Los Alamos, NM 87545, United States
AU: Bleck, R
AF: NASA GISS, 2880 Broadway, New York, NY 10025, United States
AU: Chylek, P
AF: Los Alamos National Laboratory, D462, Los Alamos, NM 87545, United States
AU: Lohmann, U
AF: ETH, Universitastasse 16, Zurich, 8092, Switzerland
AB: We report ensemble simulations of the climatic impacts of changing anthropogenic aerosols (sulfate, organic and black carbon), which bracket two policy scenarios: increased emissions over China and India by a factor of three over current levels and a global reduction of aerosols by a factor of ten, using the NCAR-CCSM3 and NASA- GISS coupled ocean atmosphere models. Tripling the anthropogenic aerosols over China and India has a small cooling effect (about -0.12°C) on the global mean surface air temperature with a slight reduction in global mean precipitation by ~ -0.8%. On the other hand, global reduction of anthropogenic aerosols by a factor of ten would warm the global surface temperatures by 0.4 °C - 0.8 °C in less than 10 years after the reduction takes place as well as an increase in global precipitation by 3.0% - 3.3%. Comparisons of NCAR and NASA model simulations also suggest that the indirect effects of aerosols are about 1-2 times the direct effects of aerosols. Tripling Asian anthropogenic aerosols results in regional cooling and a reduction in precipitation primarily in Asia, with cooling (warming) also noted over the high latitudes of Northern (Southern) Hemisphere. Warming and increase in precipitation in the case of global reduction of aerosols are concentrated mainly over polluted land areas in both hemispheres. Tropical regions experience large changes in precipitation in both scenarios. We provide new insights into the climate model sensitivities of global mean temperatures and rainfall to aerosol forcing. Our results underscore the urgency of reducing greenhouse gas accumulation rates as the world reduces air pollution to improve human health and that potential increased Asian pollution, offsets only a small fraction of the warming by greenhouse gases.
UR: http://aerosols.lanl.gov
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1637 Regional climate change
DE: 3337 Global climate models (1626, 4928)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting