Regional climate forcing of aerosol estimated by a box model for a rural site in Central Europe during summer

In the present work, a box model is applied to estimate the direct climate forcing of aerosol particles for rural air in Central Europe during summertime. In the model, the input parameters reflect regional character: data from satellite observations and other surface measurements are used referring to the selected area, Hungary. In the calculation of direct climate forcing of aerosol particles satellite observations serve as the source of incoming solar radiation intensity data and cloudiness, while different aerosol parameters of the model (mass extinction coefficient, chemical composition, scale height, hygroscopic growth factor, etc.) are based on local measurements. Finally, surface albedo of the area studied was determined on the basis of vegetation cover and precipitation amount. As the summary of our calculations, in Central Europe direct climate forcing of ammonium sulfate is equal to -2.4 W m(-2). The climate forcing of total carbon is composed of two terms. The forcings due to scattering and absorption are -1.0 and + 0.2 W m(-2), respectively. In spite of the fact that the mass concentrations of ammonium sulfate and total carbon are similar, their contribution to the aerosol direct forcing is different. We conclude that ammonium sulfate plays the major role in this process and organics have an additional impact. (C) 2002 Elsevier Science Ltd. All rights reserved.