城市空气污染数值预报试验

采用城市空气污染数值预报模式系统, 并结合天津市部分气象资料和浓度监测资料对１９９８ 年１ 月１～１５ 日的ＳＯ２、ＮＯｘ和ＴＳＰ浓度进行数值模拟和试预报。结果表明,该模式运行稳定, 计算满足预报时效要求, 对ＳＯ２和ＮＯｘ日均值预报的准确率可分别达到６４％ 和７０％ , 对ＳＯ２逐时预报的准确率为５５％ ～６２％ , 对ＴＳＰ预报的准确率低于ＳＯ２和ＮＯｘ。此次预报试验说明,该模式可作为城市空气污染数值预报的基本模式进行初步应用,但仍需进一步的研究、发展和完善     

利用中尺度模式作辽宁省空气污染气象条件预报

利用非静力中尺度数值模式（MM5V2），试验预报辽宁省空气污染气象条件。在模式中着重加密近地面的垂直分层，使用中期数值预报模式（T106L19）预报场作为初值背景场和侧边界。采用美国污染潜势预报方法，在模式预报输出市场中，通过对近地面层的混合层高度和混合层平均风速的判定，预测未来空气污染气象条件，并用SO2实测值进行检验。     

德阳市区空气污染气象指数预报

根据空气污染与气象条件的关系分析，引入一个空气污染气象指数，用T213数值预报产品相关资料作为空气污染气象因子输入，从而作出空气污染气象指数预报。     

数值预报产品在暴雨天气过程中的对比分析

本文通过对一次暴雨天气过程的天气形势及几种数值预报产品在该过程中的应用对比分析，得到了实际预报中有较好相关的预报因子。     

城市空气污染预报方法

介绍了城市空气污染预报的发展过程及几种预报方法,指出了各种方法的优缺点;介绍了城市空气污染预报问题的特点,包括预报的范围、时效及时空高分辨率;论述了复杂地形条件下采用数值模式预报污染物浓度的必要性。     

长春市空气污染潜势预报的统计模型研究

通过分析TSP污染指数与气象条件的关系，特别是一些非线性关系，建立了长春市空气污染潜势预报统计模型，借助T106及日本数值预报产品进行试报，效果较为理想。     

数值预报产品在暴雨天气过程中的对比分析

本文通过对一次暴雨天气过程的天气形势及几种数值预报产品在该过程中的应用对比分析,得到了实际预报中有较好相关的预报因子.     

城市空气污染数值预报系统CAPPS及其应用

城市空气污染数值预报系统CAPPS, 是在ADPIC的概念的基础上经过积分求得的大气平流扩散的多尺度箱格预报模型。它不需要污染源的源强资料就可预报出城市空气污染潜势指数 (PPI) 和污染指数 (API), 克服了由污染源调查本身具有的不确定性给城市空气污染的数值预报所带来的困难。该文对CAPPS系统在北京市和上海市进行数值预报的结果进行了分析检验, 并与国际上几种光化学污染预报模式的预报结果进行比较。结果表明, 就预报值与监测值的线性相关系数来说, CAPPS系统的预报水平与其他发达国家的模式预报水平相当。此外, CAPPS系统的污染指数等级预报准确率 (北京市和上海市) 平均达到61.5%。     

贵阳市空气污染数值预报的业务方法研究

使用地形跟踪坐标系上的三维动力学流场模式和平流扩散方程模式,开发了贵阳市分片区SO2污染水平预报的业务数值预报模式。城市地形和大气污染物排放源强按实际情况输入,污染气象条件则使用天气学方法预报。经贵阳市实际应用,对城市平均SO2污染指数的24h预报准确率可达80％以上。     

一个基于中尺度数值模式的城市分区空气污染预报方法

以深圳市为例，对污染物浓度与各种大气参数的定量联系进行了细致的统计及物理分析，在此基础上建立起分区的城市空气污染潜势等级预报方案。该方案定量考虑了地面和边界层共十几个因子的影响，特别是考虑了地理环境各向异性的效应，将风向作为一个独立的影响因子。方案还针对各污染物稀释特性的差异对不同污染物分别建立潜势预报方案。另外，方案还考虑了相同大气条件下大气对城市不同区域污染物稀释特性可能存在的差异，对不同区域分别建立潜势预报方案。最后用高分辨的中尺度数值模式对大气参数的未来演变作出高时空分辨的预报，进而作出分区、分时段的城市空气污染潜势预报。本方法完全客观定量，物理意义明确，可制作高时间分辨的空气污染潜势预报。     

The solubility of SO2 and the dissociation of H2SO3 in NaCl solutions

The pK ₁ ^* and pK ₂ ^* of H₂SO₃ have been determined in NaCl solutions as a function of ionic strength (0.1 to 6 m) and temperature (5 and 25 °C). The extrapolated values in water were found to be in good agreement with literature data. The experimental results have been used to determine the Pitzer interaction parameters for SO₂, HSO ₃ ^- and SO ₃ ^- in NaCl solutions. The resultant parameters for NaHSO₃ and Na₂SO₃ were found to be in reasonable agreement with the values for NaHSO₄ and Na₂SO₄. It, thus, seems reasonable to assume that the interactions of Mg²⁺ and Ca²⁺ with HSO ₃ ^- and SO ₃ ^- can be estimated from the values with HSO ₄ ^- and SO ₄ ^- until experimental values are available. Measurements of pK ₁ ^* and pK ₂ ^* in artificial seawater were found to be in good agreement with the calculated values using the derived Pitzer parameters. It is, thus, possible to make reasonable estimates of the activity coefficients of HSO ₃ ^- and SO ₃ ^- ions and pK ₁ ^* and pK ₂ ^* for the ionization of H₂SO₃ in marine aerosols.     

Mass transfer at the air/water interface: Mass accommodation coefficients of SO2, HNO3, NO2 and NH3

We present here experimental determinations of mass accommodation coefficients using a low pressure tube reactor in which monodispersed droplets, generated by a vibrating orifice, are brought into contact with known amounts of trace gases. The uptake of the gases and the accommodation coefficient are determined by chemical analysis of the aqueous phase.We report in this article measurements of _exp=(6.0±0.8)×10^–2 at 298 K and with a total pressure of 38 Torr for SO₂, (5.0±1.0)×10^–2 at 297 K and total pressure of 52 Torr for HNO₃, (1.5±0.6)×10^–3 at 298 K and total pressure of 50 Torr for NO₂, (2.4±1.0)×10^–2 at 290 K and total pressure of 70 Torr for NH₃.These values are corrected for mass transport limitations in the gas phase leading to =(1.3±0.1)×10^–1 (298 K) for SO₂, (1.1±0.1)×10^–1 (298 K) for HNO₃, (9.7±0.9)×10^–2 (290 K) for NH₃, (1.5±0.8)×10^–3 (298 K) for NO₂ but this last value should not be considered as the true value of for NO₂ because of possible chemical interferences.Results are discussed in terms of experimental conditions which determine the presence of limitations on the mass transport rates of gaseous species into an aqueous phase, which permits the correction of the experimental values.     

Model studies of the impact of chemical inhomogeneity on SO2 oxidation in warm stratiform clouds

A one-dimensional, time-dependent model of the physics and chemistry of a warm stratiform cloud is used to study the possible impact of chemical inhomogeneity among cloud and raindrops on the oxidation of SO₂ in clouds. The effects of chemical inhomogeneity are examined using two contrasting models: In Model 1 a bulk-solution parameterization is adopted which effectively treats all cloud and raindrops as if they are chemically homogeneous; in Model 2 we allow the cloud and raindrops to have a dichotomous distribution. The dichotomous distribution in Model 2 is simulated by assuming that the two groups of cloud droplets nucleate from two chemically distinct populations of condensation nuclei; one being acidic and the other being alkaline. While the two models yield essentially identical results when the ambient levels of H₂O₂ are greater than the ambient levels of SO₂, the rate of conversion of SO₂ to sulfuric acid and the amount of sulfate removed in the precipitation can be significantly enhanced in Model 2 over that of Model 1 under conditions of oxidant limitation (i.e., H₂O₂ < SO₂). This enhancement is critically dependent upon the fraction of alkaline nuclei assumed to be present in Model 2 and arises from the rapid increase in the aqueous-phase reaction between O₃+S_IV at high pH. Our results suggest that cloud models which adopt a bulk-solution parameterization for cloud droplet chemistry, may underestimate the amount of in-cloud SO₂ oxidation under oxidant-limited conditions.     

A Study of DMS Oxidation in the Tropics: Comparison of Christmas Island Field Observations of DMS, SO2, and DMSO with Model Simulations

This study reports comparisonsbetween model simulations, based on current sulfurmechanisms, with the DMS, SO₂ and DMSOobservational data reported by Bandy et al.(1996) in their 1994 Christmas Island field study. For both DMS and SO₂, the model results werefound to be in excellent agreement with theobservations when the observations were filtered so asto establish a common meteorological environment. Thisfiltered DMS and SO₂ data encompassedapproximately half of the total sampled days. Basedon these composite profiles, it was shown thatoxidation of DMS via OH was the dominant pathway withno more than 5 to 15% proceeding through Cl atoms andless than 3% through NO₃. This analysis wasbased on an estimated DMS sea-to-air flux of 3.4 ×10⁹ molecs cm^-2 s^-1. The dominant sourceof BL SO₂ was oxidation of DMS, the overallconversion efficiency being evaluated at 0.65 ± 0.15. The major loss of SO₂ was deposition to theocean's surface and scavenging by aerosol. Theresulting combined first order k value was estimated at 1.6 × 10^-5 s^-1. In contrast to the DMSand SO₂ simulations, the model under-predictedthe observed DMSO levels by nearly a factor of 50. Although DMSO instrument measurement problems can notbe totally ruled out, the possibility of DMSO sourcesother than gas phase oxidation of DMS must beseriously considered and should be explored in futurestudies.