PARAGON: An Integrated Approach for Characterizing Aerosol Climate Impacts and Environmental Interactions

OCTOBER 2004 AMERICAN METEOROLOGICAL SOCIETY | A erosols are airborne suspensions of tiny particles, each typically about one-thousandth the diameter of the period at the end of this sentence. Cumulatively, they have profound effects at a variety of scales, exerting myriad influences on the earth’s environment and climate and on human health. Many aerosols originate from natural sources—volcanoes, dust storms, forest and grassland fires, terrestrial and oceanic vegetation, and sea spray—whereas others arise from anthropogenic (human caused) sources. The sources of anthropogenic aerosols include the burning of fossil and biofuels— through industrial activities, transportation systems, and urban heating—along with land cover/land-use changes, for example, biomass burning, deforestation, and desertification. Scattering and absorption of sunlight leads to a “direct” radiative forcing of climate, which, when included in model calculations, results in improved agreement with observed temperature trends over the last century (Penner et al. 2001; PARAGON An Integrated Approach for Characterizing Aerosol Climate Impacts and Environmental Interactions