西沙群岛旱季小阵雨的酸度及化学成分

The acidity and chemical composition of showery rain over -Xisha Islands in dry season

The paper analyzes samples of showery rain taken in Novmber, 1988 in Yongxing Is.and shenhang Is.,Xisha Islands, when northeast monsoon was prevailing .The results suggest that pH values of the samples are between 5.90-7.45. The concentration of ions is greater than that of thumder showers of southwest summer monsoon. The concentration of chlorine and sodium ions are large, which are about 86.6%and 59.8% of the anion and cation in total, respectively. The equivalent ratio of chlorine to sulfate iong is 7.6, Contrasting with sulfate predominance in cation for the mainland of China. The enriching processes of K⁺,Ca⁺⁺,Mg⁺⁺, and SO^-₄ are in varying degrees. The SO^-₄ and F^- of "extraquantity" are from the continent of East Asia.