Yet observational and modeling studies have shown that these aerosols have led to large regional changes in surface and atmospheric temperatures, the surface energy budget, and rainfall (Ramanathan et al., 2001a; Chung et al., 2002; Menon et al., 2002b).

East Asian Pollution Observed over the Western Pacific Ocean

Similar regional averaged forcing values computed in a model constrained by observations have been obtained for the western Pacific region off East Asia using data from the Aerosol Characterization Experiment in Asia (ACE-Asia) field campaign (Conant et al., 2003). The figure below shows direct surface forcing, atmospheric forcing, and TOA forcing for the region averaged over 10 days of observations. The magnitudes are comparable to those obtained for the Indian Ocean.

Direct aerosol forcing for April 5 to 15 computed with a model constrained by ACE-Asia observations. The values are averaged over 20°N to 50°N and 100°E to 150°E. Results are shown from three versions of the model: externally mixed aerosol and clear-sky conditions; internally mixed aerosol and clear-sky conditions; and all-sky (clear and cloudy) conditions. SOURCE: Conant et al. (2003).

energy balance. Together with the TOA radiative forcing, surface radiative forcing also may provide information about the extent to which forcings affect the atmospheric lapse rate, with implications for precipitation and mixing. The net radiative forcing of the atmosphere could be deduced from the difference between TOA and surface forcing. Like the other metrics discussed above, global mean radiative forcing at the surface would not allow characterization of the regional structure of forcing.

Reporting surface radiative forcing along with that at the TOA is im-



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