Direct And Indirect Effect Of Aerosols On The Climate Of The Southeastern U.S.

摘要

The effect of sulfate aerosols on cloud microphysical and optical properties has been studied using field measurements from a rural mountaintop location at the Mt. Mitchell State Park in the southeastern U.S. The sulfate concentrations were greater during 1993-97 than during 1986-89. Cloud albedo retrieved from satellite data and calculated from surface observations does not indicate a monotonic increase with increasing sulfates. The direct and cloud-mediated radiative forcing effects due to sulfate aerosols are assessed to be -4.8 and ～-4.0 Wm~(-2). These values far exceed the existing model predictions. Surface temperature records of the region during 1949-94 indicate a cooling trend tacitly supporting our assessment.