%0 Journal Article
%T Evaluation of Regional Climatic Model Simulated Aerosol Optical Properties over South Africa Using Ground-Based and Satellite Observations
%A M. Tesfaye
%A J. Botai
%A V. Sivakumar
%A G. Mengistu Tsidu
%J ISRN Atmospheric Sciences
%D 2013
%R 10.1155/2013/237483
%X The present study evaluates the aerosol optical property computing performance of the Regional Climate Model (RegCM4) which is interactively coupled with anthropogenic-desert dust schemes, in South Africa. The validation was carried out by comparing RegCM4 estimated: aerosol extinction coefficient profile, Aerosol Optical Depth (AOD), and Single Scattering Albedo (SSA) with AERONET, LIDAR, and MISR observations. The results showed that the magnitudes of simulated AOD at the Skukuza station (24¡ãS, 31¡ãE) are within the standard deviation of AERONET and ¡À25% of MISR observations. Within the latitudinal range of 26.5¡ãS to 24.5¡ãS, simulated AOD and SSA values are within the standard deviation of MISR retrievals. However, within the latitude range of 33.5¡ãS to 27¡ãS, the model exhibited enhanced AOD and SSA values when compared with MISR observations. This is primarily associated with the dry bias in simulated precipitation that leads to the overestimation of dust emission and underestimation of aerosol wet deposition. With respect to LIDAR, the model performed well in capturing the major aerosol extinction profiles. Overall, the results showed that RegCM4 has a good ability in reproducing the major observational features of aerosol optical fields over the area of interest. 1. Introduction Atmospheric aerosols which originate from different natural events (e.g., wind-blown dust and sea salt particles) and human activities such as combustion of biomass and fossil fuels, as well as various industrial processes (e.g., sulfates, nitrates, ammonium, and carbonaceous aerosols) are ubiquitous in the Earth¡¯s atmosphere [1]. Relative to the well mixed and long-lived greenhouse gases, one of the main typical properties of atmospheric aerosols is their immense diversity, not only with respect to their physicochemical and optical properties, but also with regards to their spatial and temporal distributions (e.g., [2]). This is attributed to their diverse local source mechanisms, rapid aging, and chemical transformation processes, as well as short lifetime [3]. Though, owing to these heterogeneous properties of aerosols, the quantification of their climatic roles remains with large uncertainties; they are increasingly reported as one of the crucial components of the atmosphere for multi-climatic issues ([4] and references therein). Primarily, atmospheric aerosols play an important role in modulating the regional radiation budget either through scattering or absorption of radiation (direct effects) (e.g., [5]). The perturbation of the radiation balance of the Earth through
%U http://www.hindawi.com/journals/isrn.atmospheric.sciences/2013/237483/