共查询到16条相似文献,搜索用时 171 毫秒
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本文利用云内成雨清除模式和云下雨水冲刷清除模式讨论了云内和云下致酸物质的清除、酸化过程。计算结果表明,雨不酸化主要是在云内形成、而云底之下雨水对清除酸化过程是不重要的。而对流引起的上升气流和下沉气流对污染层内致酸物质的浓度变化有较大影响。 相似文献
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提出了一种利用SO2空中和雨水采样资料和气象资料、云物理探测资料等计算云下SO2降水清除系数的方法,计算了贵阳市冬、夏季不同雨强下的SO2除水清除系数kw,并将所得结果实际用于城市SO2浓度的数值计算。结果表明,这一方法所得结果与实际情况相当一致。 相似文献
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对辽宁农村代表区域站点——辽中县马龙村观测站2007年2月至2008年1月酸雨、气态污染物浓度观测资料进行了研究。结果表明:辽中站降水的化学组成阴离子主要为SO4^2-和NO3-阳离子主要为NH4和Ca2+,SO4^2-/NO3-比值为2.9.Na+/Cl-比值较大,大于1。各种离子浓度冬春季高,夏秋季较低,表明研究区域降水酸化与污染关系不显著。实测的9种主要阴离子、阳离子总浓度比(∑阴离子/∑阳离子)与降水pH值相关性不高,表明目前酸雨研究观测的主要9种阴阳离子不能完全包括降水中的离子组成。降水酸性与近地面污染气体浓度相关各异,pH与NOx、CO、NO2和O3浓度有较明显的负相关,与SO2浓度负相关不明显;降水pH值与颗粒物等碱性污染物浓度正相关明显。降水中主要致酸离子SO4^2-和NO3-的浓度与相应酸性气体污染物SO2和NOx近地面浓度的相关不明显。 相似文献
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A numerical model for the study of the regional acid precipitation is developed. The model consists of five parts: the distribution patterns of SO2 concentration, the mesoscale flow fields, the parameteriza-tion of SO2, transformation into SO4=, the parameterization of precipitation scavenging process, and the relationship between SO2 content in precipitation and ground level concentration of SO2 in the air. The distribution of SO2, SO2= and pH for all precipitations in Chongqing area during the period of July to October 1982 are simulated with the model. A comparison of the simulated results with experimental data shows that high SO2 concentration centres correspond to low pH centres. The source of the acid rain in Chongqing area is local air pollution which is due to the lower effective stack height, low wind velocity in the area, basin topography, and the use of coal with high sulphur content. The mechanism for the formation of the acid precipitation here may be different from that in the United States of America and the Western Europe, where acid rain appears in the area far from pollution source. 相似文献
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Wang Mingxing 《大气科学进展》1984,1(1):76-94
The acidity of precipitation in both clean and polluted areas was calculated for atmospheric CO2 and SO2 in equilibrium with water. pH values of 5 and 4.5 were obtained. In Beijing the pH value is increased due to paniculate chlorine reactivity and rainout of CaO in the atmosphere. The increase of pH value is related to liquid water content in cloud and the elemental concentrations of paniculate Cl and Ca in the atmosphere. This mechanism may help to explain the nonacid rain observed in Beijing where the air pollution problem is serious, as viewed by SO2 concentration and paniculate burden in the atmosphere. 相似文献
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Using a model of the acidification process of rain, we calculate and analyze the effects and contributions of a below-cloud aerosol in its different concentrations and acidities on the pH and ion components of rain (SO
4
2–
, H+, NO
3
–
, NH
4
+
, etc.) under the conditions of different concentrations of pollution gases. The results show that the aerosol has an acidification or alkalization effect on the rain which changes the pHs of rain and aerosol. As acidifying pollution gas concentrations (SO2, HNO3) are low, the acid aerosol has important effects on the pH and H+ of rain, but as the gas concentrations are high, the acid aerosol has very little effect. The alkalizing aerosol makes the pH of rain increase by between 0.3 and 0.5 and neutralizes about 60% of H+ in the rain. As alkalizing pollution gas NH3 exists, the acid aerosol has important effects on the pH and H+ of rain. But the alkalizing aerosol has very little effect, especially as the NH3 concentration is high. The percentage contribution of the aerosol to SO
4
2–
in rain is generally 7–15%, the contribution of the aerosol to NO
3
–
is nearly the same as that of HNO3=1 ppb, and the contribution of the aerosol to NH
4
+
is nearly the same as that of NH3, from 5 to 7 ppb, and is an important source of NH
4
+
in rain. Finally, according to the actual conditions of typical regions in the south and north of China (Chongqing and Beijing), we analyze the effects of aerosol and pollution gases on the ion components of rain. 相似文献
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提出了一种利用SO2 空中和雨水采样资料和气象资料、云物理探测资料等计算云下SO2 降水清除系数的方法 ,计算了贵阳市冬、夏季不同雨强下的SO2 降水清除系数kw,并将所得结果实际用于城市SO2 浓度的数值计算。结果表明 ,这一方法所得结果与实际情况相当一致 相似文献
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利用一个冰雹云模式与云化学模式耦合而成的二维积云化学模式,研究对流云的输送、微物理转化、云内化学过程、湿清除对SO2及硫酸盐气溶胶的作用。云化学模式的结果表明,由于SO2在向上输送的过程中可溶解于云水和雨水中,从而阻止了SO2向上部的转移,因此对气相SO2来说,云的输送是一个相当无效的过程,而液相清除起主要作用。硫酸盐气溶胶的收支分析表明,降水清除了1.67 mol的SO2-4,占气溶胶总量的64%,其中液态降水清除了0.72 mol,固态降水清除了0.95 mol,说明了冰相过程在硫沉降中的重要性。 相似文献
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南岭大瑶山浓雾雾水的化学成分研究 总被引:29,自引:4,他引:29
文中利用 1998年 12月~ 1999年 1月和 2 0 0 1年 2~ 3月在南岭山地采集的雾水样品资料 ,分析了南岭山地浓雾雾水的化学成分 ;对 3次典型浓雾过程雾水的离子浓度及其可能的来源进行了分析 ;发现酸雾的频率达 5 1% ,酸雾的危害不容忽视。南岭山地的浓雾雾水中的诸离子浓度远高于雨水。不同过程雾水的化学特征变化差异明显 ,在雾水中浓度最高的阴离子是SO2 -4,其次是NO-3 ;阳离子Ca2 ,NH 4 的浓度最高。雨水比雾水酸性更强 ,说明虽然雾水中的离子浓度较雨水高得多 ,但大量的离子成分中存在更多的缓冲物质 ,比如说NH 4 和Ca2 。雾水中的Ca2 ,SO2 -4,Mg2 有明显的富集现象 ,南岭大瑶山的雾水主要受大陆环境和人类活动的影响。 相似文献