Aerosol Characteristics on the Alboran Sea, 9-18 October 1982

Abstract : An at-sea study of aerosol characteristics was conducted on the Alboran Sea to obtain data for potential correlation with sun photometry, overflight imagery and radiance data and for study of possible atmospheric/ aerosol effects produced by sea surface temperature gradients of the Alboran Gyre. Observations of Aitken nuclei concentrations, aerosol size spectra (0.3 to 30 micrometers diameter), visibility (scattering coefficient), optical depth (sun photometry), air temperature, relative humidity, winds and cloud cover were acquired hourly during daylight hours of the cruise; samples for aerosol chemical analyses were obtained at approximate 3-hr intervals. The data show that aerosol populations, even in mid-Alboran, were typical of those observed previously at other near-coastal locals, although characterized by high proportions of NaCl aerosols. The cold water of the Alboran Gyre was apparently responsible for a stable atmospheric boundary layer, along the northern shore of the Alboran, which trapped aerosol plumes from the Gibraltar area at low levels. Finally, optical depth was found to correlate with surface level visibility integrated as a function of the relative humidity profile over the boundary layer, assuming a well-mixed boundary layer with respect to aerosols.