Empirical determination of direct aerosol radiative effects in the shortwave and longwave spectral ranges during desert dust events over Valencia (Spain)

Abstract

Abstract. Five years (2007Five years ( -2011 of aerosol optical depth and radiation measurements in Valencia (Spain) have been analysed in order to study empirically the radiative perturbation produced by the dust events to shortwave and longwave spectral ranges at the Earth surface. The direct method has been applied to only cloud free observations. The aerosol produces a surface cooling by -173 and -142 W/m 2 per unit optical depth at solar zenith angles of 20º and 50º, respectively, in the shortwave range. The shortwave cooling is partially off-set by 30-40 % by the LW heating. The LW effect can be larger (up to 60%) on a daily basis since it acts continuously also during night-time.