Anthropogenic sulfate and organic aerosols, CCN, and cloud project concentration at a marine site

Conference · Fri Oct 01 04:00:00 EDT 1993

OSTI ID:10108343

Novakao, T; Rivera-Carpio, C ^[1]; Penner, J E ^[2]; Rogers, C F ^[3]

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1. Lawrence Berkeley Lab., CA (United States)
2. Lawrence Livermore National Lab., CA (United States)
3. Nevada Univ., Reno, NV (United States). Desert Research Inst.

The need to establish the relationships between the number concentration of cloud droplets, cloud condensation nuclei (CCN), and the mass concentrations of major aerosol species has been heightened by the results of recent modeling studies suggesting that anthropogenic sulfate and biomass smoke aerosols may cause a globally averaged climate forcing comparable in magnitude but opposite in sign to the forcing due to ``greenhouse`` gases. In this paper we present the results of measurements of nonseasalt (nss) sulfate and organic carbon mass concentrations and mass size distributions, CCN, and cloud droplet number concentrations obtained in 1991 and 1992 on El Yunque peak, Puerto Rico . This peak (18{degree}19N, 65{degree}45W; elevation 1000 m) is located the eastern end of the island, directly exposed to the ocean winds and frequently covered with clouds. Our results show that although CCN number concentrations (measured at 0.5% supersaturation) and nss sulfate mass concentrations are significantly correlated at this site, estimates based on measured mass size distributions of organic and sulfate aerosols indicate that the organic aerosols may account for the majority of CCN number concentrations. Droplet concentrations in the cumulus clouds do not show a discernible trend with nss sulfate mass concentrations. In stratocumulus clouds a small increase in droplet concentrations with nss sulfate mass concentrations was observed.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48; AC03-76SF00098
• OSTI ID: 10108343
• Report Number(s): UCRL-JC--115308; CONF-940115--14; ON: DE94004210
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120
AEROSOLS
CARBON
CHEMICALS MONITORING AND TRANSPORT
CLOUDS
CONDENSATION NUCLEI
ENVIRONMENTAL IMPACTS
GREENHOUSE EFFECT
SULFATES