Numerical modeling of long-range transport of acidic species in association with meso-β- convective-clouds across the Japan sea resulting in acid snow over coastal Japan—I. model description and qualitative verifications

• Published in: Atmospheric environment. Part A, General topics General topics, 1993, Vol.27 (7), p.1061-1076
• Main Authors: Kitada, Toshihiro, Lee, Pius C.S., Ueda, Hiromasa
• Format: Article
• Language: English
• Subjects: Applied sciences; Atmospheric pollution; Exact sciences and technology; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution
• ISSN: 0960-1686
• DOI: 10.1016/0960-1686(93)90141-K

This is Part I of two papers in series. Part I is dedicated to descriptions and qualitative verifications of the model, and Part II [Kitada and Lee, Atmospheric Environment 27A, 1077–1090, 1993] to discussion of model results. The model is 3-D Eulerian and includes transport/gas- and aqueous-phase chemistry/dry and wet deposition processes for chemical species in gas-phase and hydrometeor-phases of cloud water, cloud ice, rain, snow and graupel. Six aqueous species of NO 3 −, NH 4 +, S(IV), SO 4 2−, H 2O 2 and O 3 are accounted for, and the rates of interphase mass transfer processes among hydrometeors are calculated using the cloud-microphysics model presented in Rutledge and Hobbs [ J. atmos. Sci. 41, 2949–2972, 1984]. The gas-phase part of the model is based on that in Kitada et al. [ J. Clim. appl. Met. 23, 1153–1172, 1984] and Carmichael et al. [ Atmospheric Environment 20, 173–188, 1986]. The model is applied to a mid-winter snowfall event in association with meso-β-convective-clouds induced in a cold continental air flow over the warmer Japan Sea. The predicted snowfall intensities along the course of the flow agreed with those by another independent modeling study, proving the soundness of model output of the cloud microphysics fields. The predicted chemical characteristics of the event are compared with recent measurements of acid rain/snow episodes, with emphasis made to interpret those taken along the Japanese coast. Model outputs of in-cloud-air, cloud-phase, precipitated-snow-phase concentrations of the N- and S-compounds are in qualitative agreement with the data. The model results suggest that between 30 and 40% of the wintertime sulfate deposition in Kanazawa, a Japanese coastal city, can be explained by long-range transport of air pollutants from the continent.