Analysis of cloud condensation nuclei concentrations measurements during the AMF deployment in China

Description

Cloud microphysical, and also optical and radiative, properties depend on atmospheric concentrations and spectra of cloud condensation nuclei (CCN). CCN concentration is the most important factor affecting cloud microphysics properties. During the ARM Mobile Facility (AMF) deployment in China in 2008, cloud condensation nuclei (CCN) measurements were made at the Shouxian site, which is located in east of China, from 26 July to 31 October. The average CCN concentrations were 215±132, 369±178, 454±275 1/cm3 at a supersaturation of 0.20 for August, September, and October, respectively. Corresponding CCN/CN ratios were 0.125±0.078, 0.158±0.106, 0.074±0.098 at SS=0.20. During the whole observation period, the air masses over Shouxian were continental. The diurnal variation of CN and CCN showed that there were two peaks at about 8:00 am and 18:00 pm and 9:00 am and 19:00 pm, respectively, when human activities were intense. A significant increase in CCN concentration with increasing CN was measured, especially at higher SS. The relationship between CN, CCN, CCN/CN are found to be significantly influenced by air mass and meteorological conditions.