西太平洋地区大气边界层内臭氧的季节变化及其影响因子分析

利用臭氧探空资料,分析了西太平洋地区香港(Hong Kong)、那霸(Naha)和札幌(Sapporo)三个站点2000~2010年期间大气边界层内臭氧(O₃)的季节分布和年变化趋势。结果表明,三个站点O₃的季节分布存在明显的差异。其中,那霸和香港大气边界层内O₃季节平均呈双峰值分布,其峰值分别出现在春季和秋季;而札幌站为单峰分布,峰值出现在春季。造成季节分布差异的主要原因包括人为污染源和自然因素如气象条件。另外,三个站点大气边界层内O₃均呈上升趋势。其中札幌、那霸上升最快,分别达0.80 ppb a-1和0.77 ppb a-1。(ppb表示10-9,下同)香港的年际增长较不明显,但秋季增长却非常明显,高达1.21 ppb a-1。结合GOME (Global Ozone Monitoring Experiment) 和SCIAMACHY (Scanning Imaging Absorption Spectro Meter for Atmospheric Chartography)卫星反演的NO₂数据发现,过去10年中国京津唐和东北地区的对流层内NO₂柱总量增加极为迅速。这些O₃前体物通过远距离输送是导致札幌、那霸O₃浓度增加的主要原因之一。珠江三角洲人为污染源的增加及偏北气流的影响,是导致香港地区秋季O₃增加的主要原因。     

Seasonal to interannual prediction of air pollution in China:Review and insight

复合型大气污染对中国环境,健康和经济存在巨大的不利影响.2013年以来的减排措施有效改善了空气质量.目前,我国已进入大气污染与气候变化协同治理的关键阶段.在季节-年际尺度上,对大气污染(霾,臭氧和沙尘暴)的准确预测可以为有关部门的减排措施提供有效的科技技撑.近年来,全球科学家在理解中国气候变化,大气污染变率及相关物理机...     

A 24‐h Forecast of Oxidant Concentration in Tokyo Using Neural Network and Fuzzy Learning Approach

In this study, several types of adaptive network‐based fuzzy inference system (ANFIS) with different membership functions (MFs) and artificial neural network (ANN) were employed to predict hourly photochemical oxidants that were oxidizing substances such as ozone and peroxiacetyl nitrate produced by photochemical reactions. The results indicated that ANFIS statistically outperforms ANN in terms of hourly oxidant prediction. The minimum mean absolute percentage errors (MAPEs) of 4.99% could be achieved using ANFIS with bell shaped MFs. The maximum correlation coefficient, the minimum mean square errors, and the minimum root mean square errors were 0.99, 0.15, and 0.39, respectively. ANFIS's architecture consists of both ANN and fuzzy logic including linguistic expression of MFs and if‐then rules, so it can overcome the limitations of traditional neural network and increase the prediction performance.     

Spatial Distribution of SO2, NO2, and O3 Concentrations in an Industrial City of Turkey Using a Passive Sampling Method

Ambient concentrations of sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and ozone (O₃) were measured at 51 sampling points by passive sampling technique in Kocaeli, an important industrial city in Turkey. Samples were analyzed by UV‐spectrophotometry for NO₂ and O₃ and by ion chromatography for SO₂, respectively. Concentrations of SO₂, NO₂, and O₃ were determined to investigate their spatial distribution and source characterization. The sampling campaigns revealed an average concentration of 8 µg/m³ (max. 82 µg/m³) for SO₂, and 14 µg/m³ (max. 40 µg/m³) for NO₂, in summer; while average winter concentrations were 25 µg/m³ (max. 61 µg/m³) for SO₂, and 50 µg/m³ (max. 100 µg/m³) for NO₂. The maximum ozone concentrations were determined to be 86 µg/m³ in summer and 61 µg/m³ in winter downwind of the source areas of the precursor pollutant emissions. The results showed that NO₂ and SO₂ concentrations in industrial and urban areas were two to four times higher compared with rural areas in the summer and winter. In the light of the information obtained from the spatial interpolation of the pollutant concentrations, a selection of appropriate locations for continuous monitoring was suggested according to the European Community (EU) directives.     

Distributions of O3, CO and NMHCs over the rural sites in central India

The surface level measurements of O₃, CO, CH₄ and light NMHCs were made at eight different rural sites in the central part of India during February, 2004. The online analyzer was used for in-situ measurement of O₃ while air samples were collected for the analyses of CO, CH₄ and NMHCs using the gas chromatography techniques. The average mixing ratios of O₃, which were in the range of 60–90 ppbv, are significantly higher compared to the typical values reported for urban sites of India. The increase rates of O₃ in the forenoon hours were estimated to be in the range of about 8.8–10 ppbv h⁻¹. The slopes of ∆O₃/∆CO, which is an indicator of the efficiency of photochemical production, were in the range of 0.24–0.33 ppbv ppbv⁻¹. However, levels of primary pollutants e.g., NMHCs, CO, etc. at these sites were much lower than urban sites, but higher compared to previously observed values surrounding marine region of India. The estimated ratios of NMHCs and CO indicate fossil fuel combustion process as the dominant source of primary pollutants in this corridor.     

The early history of oxygen and ozone in the atmosphere

There may have been three stages in the growth of oxygen in the terrestrial atmosphere. Prior to the origin of photosynthesis the only source of oxygen was photolysis of water vapor followed by escape of hydrogen to space. The rate of this process was probably less than the rate of release of reduced gases (principally hydrogen) from volcanoes, so the oxygen partial pressure was held to negligibly low values by photochemical reactions with an excess of hydrogen. The photosynthetic source of oxygen was probably in operation as long ago as 3.8 billion years. It released oxygen to the ocean. Presumably most of this oxygen was destroyed in the ocean as long as its rate of supply was less than the rate of supply of readily oxidizable material (principally Fe²⁺) provided by the weathering of rocks. This phase appears to have lasted until about 2 billion years ago, during which period most banded iron formations were deposited. During this period the production of oxygen by algae was limited by competition with photosynthetic bacteria, which preempted the supply of nutrient phosphorus as long as reduced chemicals were available in the environment. Once the photosynthetic oxygen source exceeded the rate of supply of reduced minerals exposed by erosion and weathering, the accumulation of oxygen in the ocean and atmosphere could be controlled only by reaction of oxygen with reduced organic material. This is the stabilization mechanism that operates today. It seems unlikely that oxygen could be consumed at a significant rate by this process until oxygen levels sufficiently high to support respiration had been achieved. I therefore suggest that atmospheric oxygen rose rapidly from essentially zero to approximately its present value (within a factor of 10) when the photosynthetic source of oxygen rose above the weathering source of reduced minerals, probably about 2 billion years ago. The ozone layer and the ultraviolet screen were absent prior to this time and essentially fully developed after this time.Presented at IAGA/IAMAP Symposium on Minor Neutral Constituents in Middle Atmosphere-Chemistry and Transport, Seattle, August, 1977.     

Vertical ozone distribution on a global scale

All available data of the vertical ozone distribution measured with chemical sondes have been assembled and combined with one year's results from the BUV satellite to obtain the best possible information on the vertical ozone distribution averaged over longitude as a function of season (month by month). For the southern hemisphere Umkehr data have been used as a guideline in the necessary smoothing procedure. Especially in the northern hemisphere considerable adaptation to the observed latitudinal mean of the total amount was needed because most sounding stations, are situated in upper air trough positions.The results are presented as vertical distributions, as meridional cross sections of partial pressure and of mixing ratio and as partial pressure isolines as a function of latitude and season at different levels. The interaction between photochemical processes and transport resonsible for the observed distribution is briefly discussed.     

Annual variation of the effects of diffuse radiation on the photodissociation of ozone

Previous work has shown the importance of the diffuse solar field in the photochemistry of atmospheric active species, the solar zenith angle being an effective parameter. In view of the diurnal and seasonal variability of this single quantity, in this paper estimates are presented of the daily-integrated values of the photodissociation coefficient of ozone throughout the year, for a purely molecular atmosphere in the absence of scattering and when the effects of molecular scattering are included, and for an absorbing-scattering turbid atmosphere characterized by two different aerosol loads. Also, different values of the ground albedo have been taken into account.Results are shown for a latitude of 45^oN. The seasonal dependence is strong at altitudes below 20 km and less marked above 20 km. For an albedoA=0.3, the inclusion of molecular scattering increases the daily-integrated photodissociation coefficients approximately by 20% and 40% at 15 km and by 15% and 22% at 30 km, at the winter and summer solstice respectively. The presence of a heavy aerosol load modifies these results by a further factor which is approximately –5% and 10% at 15 km at the winter and summer solstice respectively, and is approximately constant at 8% throughout the year at 30 km.     

Systems modelling of stratospheric ozone transport and photochemistry

A scheme of a system of physical and chemical processes controlling the production, transport and destruction of ozone and its gaseous catalysts, as well as other related gases in the low and high stratosphere is presented. An account is made of temperature variations of the stratospheric layer resulting from changes in ozone content; also included is the effect of temperature variations on photochemical reaction rates and ozone and other gases transport between atmospheric layers. Parameters describing major relations of the system are inferred from the analysis of ozone and trace gas data and from the results of model calculations of interdependence between variations in temperature and ozone content of the layer.An analysis of minor fluctuations of the linearized system shows that photochemical processes are responsible for its aperiodic stability and that gas transport between atmospheric layers destabilizes the system.     

Instantaneous global ozone balance including observed nitrogen dioxide

The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an important part of the global ozone balance. The lack of sufficient measurements of NO _x concentrations has impeded efforts to quantify this process. Recent measurements of stratospheric nitrogen dioxide from ground-based stations as well as aircraft and balloons have provided a first approximation to a global distribution of NO₂ vertical columns at sunset. These observed vertical columns have been translated into time-dependent vertical NO₂ profiles by means of a one-dimensional atmospheric photochemical model. Using recent observations of air temperature and ozone along with this information, the independent instantaneous (one second) rates of ozone production from oxygen photolysis P(O₃), of ozone destruction from pure oxygen species (Chapman reactions) L(O _x ), and of ozone destruction by nitrogen oxides L(NO _x ) were estimated over the three-dimensional atmosphere. These quantities are displayed as zonal average contour maps, summed over various latitude zones, summed over various altitude bands, and integrated globally between 15 and 45 km. Although the global summation between 15 and 45 km by no means tells the complete story, these numbers are of some interest, and the relative values are: P(O₃), 100; L(O _x ), 15; L(NO _x ), 45±15. It is to be emphasized that this relative NO _x contribution to the integrated ozone balance is not a measure of the sensitivity of ozone to possible perturbations of stratospheric NO _x ; recent model results must be examined for current estimates of this sensitivity.