摘要
对热带西太平洋定点（４°Ｓ，１５６°Ｅ）海域长达４个月的降水化学调查，研究了降水中化学成分的变化特征、连续性与断续性降水过程和西风暴发事件（ＷＷＢＥ）及大风暴降雨过程中降水的化学成分。结果表明：定点海域（４°Ｓ，１５６°Ｅ）纯“海洋性”降水的ｐＨ为５．５５，其Ｍｎ／Ｆｅ比值为０．５４，Ｃｌ－与ＳＯ２－４是降水中最大量的离子；连续性降水ｐＨ呈“∨”型分布，Ｅｈ呈“∧”分布，总－２价硫的浓度Ｓ（－Ⅱ）呈降低分布，且最后趋于稳定，ＳＯ２－４，ＮＨ＋４，ＰＯ３－４等在降雨开始后一段时间出现最大值，呈现与其它组分相反的行为；断续性降水ｐＨ，Ｅｈ趋于升高。西风暴发事件（ＷＷＢＥ）期间，绝大多数组分在降水中浓度高于ＷＷＢＥ发生前、后的浓度，而ＮＨ＋４低于ＷＷＢＥ发生前、后的浓度，ＰＯ３－４，ＳｉＯ２－３则是低于ＷＷＢＥ发生前的浓度，而高于发生后的浓度，大风暴降雨Ｃｌ－，ＳＯ２－４的浓度比正常降雨时可高达数倍，说明海上大风暴使大量海水滴被卷入空中，又随降雨落下，这时的降水ｐＨ也有显著增高。
This paper deals with the characteristics of rainwater chemical composition including continuous and intermittent rainwater, raindrop processes in Westerly Wind Burst Event (WWBE) and in strong windstorm at the point of tropical west Pacific (4°S,156°E) from Nov. 1992 to Feb. 1993. The results show that the pH value of pure 'marine' rainwater is 5.55 and its Mn/Fe ratio is 0.54 at 4°S,156°E. Cl - and SO 2- 4 are the main ions in rainwaters. The distribution of pH is the shape of 'V' and Eh '∧'. ∑S(-Ⅱ) has a decrese tendency with time and it tends to constant at last in continuous raindrop process. The pH and Eh have a increse tendency in intermittent raindrop process. The maximums of SO 2- 4, NH + 4, PO 3- 4 et al. occur after raindrop and maybe they are sub products in raindrop process. The invese behaviour of NH + 4, PO 3- 4, et al. to the other ions demonstrate that the mechanism of NH + 4, PO 3- 4, SO 2- 4, SiO 2- 3, ∑S(-Ⅱ) produce and wash is different from the other ions in rainwaters. The concentrations of most components during WWBE are higher than those of raindrop occured before and after WWBE, but NH + 4 is different. The concentrations of Cl - and SO 2- 4 in strong windstorm raindrop process are several times in normal raindrop, and the pH value has a distinct increse. This proved that seawater was carried by strong windstorm to air and droped with raindrop.
出处
《气象学报》
CSCD
北大核心
1997年第5期634-640,共7页
Acta Meteorologica Sinica
基金
国际合作TOGA-COARE资助
关键词
降水
化学特征
热带
西太平洋
定点海域
Rainwater chemistry, The point at tropical west Pacific (4°S,156°E), Westerly Wind Burst Event (WWBE)。
