Modeling aerosol-radiation-cloud and precipitation processes

Abstract

The Mediterranean region is characterized by unique climatic conditions and associated physico-chemical processes. The mixture of air pollutants of different age may lead to the formation of other particulate matter (PM) with different characteristics. More specifically, the coexistence of gas and aerosol pollutants from anthropogenic and natural sources (desert dust and sea salt) results in the formation of new types of PM with different physico-chemical properties and altered hygroscopicity (e.g. inside clouds or within the marine boundary layer) through heterogeneous processes. These new particles have different characteristics and therefore they have different impacts on cloud formation and precipitation. Investigating the influence of air quality on meteorology and especially on cloud physics and precipitation is one of the most challenging topics in modern atmospheric science. Airborne particles of natural or anthropogenic origin, may act as efficient Cloud Condensation Nuclei (CCN), depending on their concentrations, their size distributions and their chemical composition. Some particles, such as mineral dust, may also act as Ice Nuclei (IN) and contribute in the formation of ice particles in high clouds. Apart from the ability of aerosol particles to form cloud droplets, they do also interfere with atmospheric conditions by altering the radiation pattern as they can absorb and scatter at both shortwave and longwave parts of the radiation spectrum. The complexity of the above processes and the possible interactions and feedbacks that interfere in the system, indicate the need of an integrated approach in order in order to examine the impacts of air quality on meteorology and visa-versa. In this paper, some preliminary results concerning the impact of dust and sea salt on air quality, clouds and precipitation will be discussed.