Permalink :  http://hdl.handle.net/2115/55023

Aerosols have a substantial impact on the Earth’s radiation budget by directly scattering and absorbing the incoming solar radiation. However, our knowledge of the role of aerosols in the climate changes is not complete due to strong spatial and temporal variability of aerosols. In this paper, we first described the basis to understand the relationships between optical properties and direct effect of aerosols,and introduced the methods to observe the optical properties by in-situ measurements and by passive and active remote sensing. Next, we indicated the results of the decadal variations of optical properties and direct effect in Japan by the ground-based solar radiation measurements. Furthermore, using our developed one dimensional atmospheric boundary layer model with the radiative transfer model, we investigated the impacts of the decadal variations on the atmospheric boundary layer. The results showed the possibility that the following feedback process has a large impact on the atmospheric boundary layer: (1) change in solar radiation at the surface, (2) changes in evaporation at the surface and water vapor amount in the atmosphere, and (3) change in atmospheric cooling by the infrared radiation. These results indicate an importance of the long-term observation of aerosols to better understand the climate change.

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