Aerosol-induced Changes Research Articles

Arctic aerosols: Model estimates of interactive influences upon the surface-atmosphere clearsky radiation budget

It is known that a significant fraction of the Arctic's tropospheric aerosol is of anthropogenic origin. But in order to interpret the possible impact of this anthropogenic component upon the Arctic climate, it is necessary to understand how the aerosol alters the radiation budget of the Arctic's surface-troposphere system. The present study addresses several aspects of this possible radiative perturbation, such as the importance of the aerosol's vertical distribution, the importance of vertical variations of aerosol optical properties as induced by vertical variations of relative humidity, the estimation of diurnally-averaged seasonal perturbations of the surface-troposphere system and how these are influenced by interactions between the anthropogenic and natural components of the aerosol and a suggestion as to how to interpret observed aerosol-induced changes in the surface radiation budget.

Aerosol-Induced Albedo Change: Measurement and Modeling of an Incident

Abstract Many theoretical studies have shown that aerosol-induced changes in the earth-atmosphere albedo might be an important climate change mechanism. However, there has been a lack of experimental documentation of albedo changes caused by actual aerosol layers with measured properties. Here we report an incident in which the measured surface-plus-atmosphere albedo was increased by about 0.01 (from 0.11 to 0.12) by a transient aerosol layer. We also report simultaneous measurements of the aerosol by a multi-wavelength sunphotometer, a lidar, a nephelometer and other radiometers, and we use these aerosol measurements to deduce an expected albedo change for comparison to the measurements. Specifically, we combine the aerosol measurements with several assumed refractive indices to derive a time-dependent aerosol optical model for the day of the incident. We then use this model in a two-stream radiative calculation to compute the expected time-dependent aerosol-layer albedo. Finally, we compute aerosol-plus...