Seasonal Changes in the Concentrations of Major Cations and Anions in Precipitations in Urban Nagoya, Japan
Seasonal Changes in the Concentrations of Major Cations and Anions in Precipitations in Urban Nagoya, Japan
复制标题
日本名古屋市区降水中主要阳离子和阴离子浓度的季节变化
DOI：
10.2151/jmsj1965.76.1_13
复制
发表时间：
1998
影响因子：
3.1
通讯作者：
Y. Iwasaka
中科院分区：
文献类型：
--
作者：
H. Minoura;Shiho Mizawa;Y. Iwasaka
1993年4月1日至1994年3月31日，在日本名古屋以东16公里的名古屋，对每0.5 mm降水连续采样(平均采样时间19min)和雨水中的离子进行了分析，以详细了解降水中离子浓度的时间变化。雨水的平均pH值为4.76，硝酸盐(NO3-)为14.5μeq L-1，非季节性硫酸盐(NSS-SO42-)为18.0μeq L-1。这项研究中获得的离子平均浓度大约是日本环境厅1984年至1986年期间获得的离子浓度的一半，这被认为是由于1993年雨季较长或近年来二氧化硫排放减少造成的。离子浓度的季节变化表明，它们受到亚洲沙尘暴和台风的显著影响。亚洲沙尘暴和台风在表征日本降水化学方面起着重要作用。在伴随着天气变化的个别降水中，离子浓度在几分钟内经常发生快速变化。NO3-、NH4+、SO42-浓度随风速增大而降低，而Na+、Cl2-浓度随风速增大而增大，表现出离子产生和沉积过程的差异。南风向雨样中NO3-和NSS-SO42-浓度较高，与南风向离子源工业设施密切相关。从名古屋郊区输送的铵离子(NH4+)比从市中心输送的NH4+多。这项测量(短期采样和连续观测)显示了典型的降水化学特征，特别是在东亚区域郊区观察到的主要阳离子和阴离子的季节性浓度变化和离子传输过程。
A continuous sampling at every 0.5 mm of precipitation during rain (average sampling time of 19 minutes) and analyses of ions involved in the rainwater were carried out from April 1, 1993 to March 31, 1994 in Nagakute, 16 km east of Nagoya, Japan, to understand temporal changes in ion concentrations in precipitation in detail. The average pH, nitrate (NO 3 - ), and non-seasalt sulfate (nss-SO 4 2- ) in the collected rainwaters were 4.76, 14.5 μeq l -1 and 18.0 μeq l -1 , respectively. The average concentrations of ions obtained in this study were about half of those obtained during 1984 and 1986 by the Japan Environmental Agency, which was thought to be caused by either the longer rainy season in 1993 or the reduction of sulfur dioxide emission in recent years. The seasonal changes in ion concentrations show that they were significantly influenced by Asian dust storms and typhoons. Asian dust storms and typhoons were found to play important role in characterizing the precipitation chemistry in Japan. A rapid change in ion concentrations during several minutes was frequently found in individual precipitation accompanied by weather change. Concentrations of NO 3 - , NH 4 + , and SO 4 2- decreased with an increase in wind speed, while those of Na + and Cl - increased , showing the differences in the production and the deposition processes of ions. Higher concentrations of NO 3 - and nss-SO 4 2- in rain samples with southern wind direction were frequently observed, showing a clcar relation to the industrial facilities of ion sources located in the southern direction. A greater amount of ammonium ion (NH 4 + ) was observed to be transported from the suburbs of Nagoya rather than from the downtown area. This measurement (short period sampling and continuous observation) showed characteristics typical of a precipitation chemistry, especially for the seasonal concentration change in major cations and anions and ion transport processes, observed in suburbs in the eastern Asia region.