Geosciences Dept. Seminar: Effect of sea breeze circulation on aerosol mixing state and radiative properties in a desert setting

Abstract: 

Chemical composition, microphysical and optical properties of atmospheric aerosol deep inland in the Negev Desert of Israel were found be influenced by daily occurrences of sea breeze flow from the Mediterranean Sea. Abrupt increases in aerosol concentration and shifts of size distributions towards larger sizes, which are associated with increase in wind speed and atmospheric water content, were systematically recorded during the summertime at a distance of at least 80 km from the coast. Chemical imaging of aerosol samples confirmed presence of highly hygroscopic marine aerosols and internally mixed sea salt and mineral dust particles. Additionally, numerous particles with residuals of liquid coating were observed by SEM/EDX analysis. Measurements of the solar and thermal infrared radiation manifested variability related to the changes in aerosol properties induced by the sea breeze, e.g., the shortwave radiative cooling at the surface was doubled from -10 to -20.5 Wm-2. In addition, since an important number of the observed particles had a liquid coating, implication of this inhomogeneity for remote sensing algorithms is discussed. It is important because most of the present day atmospheric remote sensing applications rely on a simplified assumption of aerosol particles homogeneity.

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Seminar Organizer: Prof. Eyal Haifetz