资源环境科技发展态势分析平台

Fifteen years of Aqua Clouds and the Earth's Radiant Energy Systems ( CERES) and MOderate resolution Imaging Spectroradiometer ( MODIS) observations are combined to derive nearly global maps of shortwave albedo ( A) and flux ( F) response to changes in cloud droplet number concentration ( Nd). Absolute ( Sa 1/4. A. Nd) and relative ( Sr 1/4. A. ln Nd o thorn) albedo susceptibilities are computed by exploiting the linear relationship between A and ln ( Nd) for shallow liquid clouds. Subtropical stratiform clouds over the eastern Pacific, eastern Atlantic, and off the coast of eastern Asia yield the highest Sr, followed by the extratropical oceans during their hemispheric summer. When Sr is cast in terms of F, the eastern Pacific clouds dominate Sr. Sa is mainly governed by Nd, with offshore clouds producing high Sa. While both Sa and Sr are advantageous for understanding radiative aspects of the aerosol indirect effect, Sr is more suitable for calculating changes in A and F due to the linearity of the A- ln ( Nd) relationship.

Plain Language Summary The amount of solar radiation reflected back to space is strongly controlled by liquid clouds. These clouds are highly sensitive to changes in the environmental conditions due to both natural and anthropogenic factors. Atmospheric aerosols can regulate the cloud microstructure by modifying the number of droplets in the cloud. These changes can lead to an enhancement of the solar energy reflected by clouds. Here satellite data from two sensors are combined to quantify the amount of reflected solar radiation associated with changes in the cloud droplet number concentration. Results are shown globally, with an emphasis in the nonpolar oceanic regions, where liquids clouds tend to be more frequent. The results presented in this study can help shed light into the processes that modulate the cloud radiative response due to aerosol-cloud interactions.