caa a22 4500 477061060 CHVBK 20180405111400.0 cr unu---uuuuu 170330e19960501xx s 000 0 eng 10.1007/BF00053822 doi (NATIONALLICENCE)springer-10.1007/BF00053822 Rapid change in nitrate and sulfate concentrations observed in early stage of precipitation and their deposition processes [Elektronische Daten] [Hiroaki Minoura, Yasunobu Iwasaka] The concentrations of H+, nitrate (NO3 -), and sulfate (SO4 2-) in rainwater and their temporal changes were analyzed on the basis of continuous observation from 1 July 1991 to 30 June 1992 at a suburb of Nagoya, Japan. The yearly average for pH was 4.4. In general, an increasing pH with increase in precipitation amount was observed for rain events. Relatively high pH rainwater was sometimes observed at the beginning of rainfall, even though high concentrations of NO3 - and SO4 2- were involved. The high pH values were considered to be caused by the neutralization process with particulate matter containing cations. The yearly averaged ratio of equivalent concentration of nitrate to sulfate (N/S) in rainwater was 0.58. In the early stage of rain, the N/S value was usually more than 1.0 due to the difference of scavenging process between NO3 - and SO4 2-. High values of N/S ranging from 5 to 10 were found under the atmospheric conditions of calm winds and low humidity, during which it is possible that atmospheric particles float for a long time in the air before a rain event. The adsorption of NO3 - in the early stage of rainfall by particulate matter was suggested from the difference in scavenging processes of NO3 - and SO4 2-. A possible scavenging process, called limb cloud scavenging, is presented to explain the interaction of particles and nitrate ions at the early stage of rain. In limb cloud scavenging, the repeated migration of cloud particles or raindrops between the inside and outside of clouds increases the absorption of ions to a highly condensed level, thus increasing the N/S value of rainwater. The influence of global scale seasonal phenomena with large amounts of particulates, such as typhoons or Asian dust storms, was also studied. Kluwer Academic Publishers, 1996 acid rain nationallicence scavenging process nationallicence pH, nitrate nationallicence sulfate nationallicence Japan nationallicence Minoura Hiroaki Toyota Central Research & Development Laboratories, Inc., 480-11, Nagakute, Aich, Japan aut Iwasaka Yasunobu Solar-Terrestrial Environment Laboratory, Nagoya University, 465, Nagoya, Japan aut Journal of Atmospheric Chemistry Kluwer Academic Publishers; gopher://gopher.wkap.nl 24/1(1996-05-01), 39-55 0167-7764 24:1<39 1996 24 10874 https://doi.org/10.1007/BF00053822 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00053822 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Minoura Hiroaki Toyota Central Research & Development Laboratories, Inc., 480-11, Nagakute, Aich, Japan aut NATIONALLICENCE 700 1- Iwasaka Yasunobu Solar-Terrestrial Environment Laboratory, Nagoya University, 465, Nagoya, Japan aut NATIONALLICENCE 773 0- Journal of Atmospheric Chemistry Kluwer Academic Publishers; gopher://gopher.wkap.nl/ 24/1(1996-05-01), 39-55 0167-7764 24:1<39 1996 24 10874 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer