• 关键词：西太平洋  雨滴谱  降水化学  后向轨迹  非海盐源  湿沉降通量

• 基金项目：

• 肖辉
• 中国科学院大气物理研究所,北京100029

• 沈志来
• 中国科学院大气物理研究所,北京100029

• 黄美元
• 中国科学院大气物理研究所,北京100029

• 摘要：1988年9-10月在西太平洋热带海域收集了46个雨水样品和388份雨滴谱。分析结果表明,3个pH值范围下的平均两滴谱的分布基本上满足指数递减律,在风系作用下,远距离输送来的陆上物质对该海域雨水的酸度和化学组成有很大影响。“海洋性”降雨的平均pH值为5.73,而“陆地性”降雨的平均pH值只有4.80.pH5.73可认为是TWPA上未受陆地源直接影响的天然降雨的平均pH值。最后还给出了观测期间该海域非海盐化学组分的湿沉降通量。

• Abstract：6 rainwater samples and388 raindrop spectra were collected over the Tropical WestPacific Area(TWPA ) from September 26 to October 27 in 1988.The analysis resultsshowed that the distributions of raindrop spectra for three pH ranges basically conformed toan exponential lapse law. With the aid of wind system,the fong-range exponential lapselaw. With the aid of wind system,the long-range atmospheric transport of terrestrial mate-rials had a major impact on acidities and chemical constituents of rainwater over the TWPA.Over the TWPA,the rainwater in the “maritime”pricipitation was not acidic with a voL-ume-weighted mean(vwm)pH of 5. 73, while the rainwater in the“continental”precipi-taiton was more acidic with a vwm-pH of 4.80.The pH value of 5.73 could be consideredthe natural vwm-pH over the TWPA once the contributions form terrestrial material wereremoved.The influences of non-sea-salt origins on the concentrations of sulfate(SO)andcalcium(Ca²⁺)in the “continental” pricipitaiton were larger than in the “maritime”pricipi-tation,The total wet deposition fluxes of non-sea-salt components caused by preoipitationover the TWPA were also presented.

• Key words：the West Pacific  raindrop spectra  precipitaiton chemistry  back trajectca-rles  non-sea-salt origins  wet deposition fluxes

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