1992—2012年浙江省酸雨变化特征及成因分析

为了解20世纪90年代以来,浙江地区酸雨污染的演变特征及成因,以杭州地区为代表,结合全省酸雨监测数据,揭示1992—2012年浙江省酸雨变化特征及成因。结果表明：1992—2012年,浙江地区酸雨的污染大致经历了3个阶段：1992—1999年为酸雨改善期;2000—2004年酸雨污染再次出现了恶化;2005—2012年为酸雨再次改善期。SO₂排放减少是近年来浙江地区酸雨污染出现好转的重要原因,但NO_x对酸雨的贡献有增加的趋势,酸雨污染类型逐渐由"硫酸型"为主转变为"硫酸硝酸混合型",机动车排放对浙江地区酸雨污染的贡献已不容忽视。全省强酸雨区主要分布在浙北、浙中和东部沿海等经济发达地区,经济相对落后的浙西南地区酸雨污染较轻,酸雨污染与地区经济发展密切相关,控制本地污染排放对于防治和减轻当地酸雨污染具有重要意义。     

基于气流轨迹聚类分析方法浅析桂林市酸雨来源

通过对桂林市2009—2013年的酸雨状况及变化趋势分析,结果表明:桂林市酸雨强度及频率从2010年出现峰值后,呈现逐渐下降的趋势;酸雨的季节分布差异明显,冬、春季酸雨频率较高,夏季相对较低;酸雨中的阴离子主要为SO2-4和NO-3,阳离子主要为Ca2+和NH+4。利用后向轨迹和聚类分析方法对桂林市酸雨来源进行气流轨迹模拟分析,结果显示,主要作用气流来自南方地区,其中东南和偏东南方向气流形成的降雨酸性较强,酸雨频率较高。     

宁波市“十二五”与“十一五”期间酸雨污染特征变化趋势分析

基于地面观测数据,分析了"十一五"和"十二五"期间宁波市酸雨污染特征变化趋势。结果表明,2015年降水pH从2010年的4.37上升到4.89;2010—2015年酸雨发生频率降低了17.4百分点;重酸雨区范围不断缩小,轻酸雨区范围不断扩大,酸雨污染程度有所改善。降水中化学组成变化显示,与"十一五"末相比,2015年除NO_3~-、Cl~-外其他离子浓度均有所下降;2015年SO_3~(2-)与NO_3~-的当量浓度之比从2010年的3.10下降到1.73,表明酸雨污染从硫酸型向硫酸与硝酸混合型转变。     

泰州市降水主要特征及酸雨成因浅析

对泰州市1996年—2000年降水主要特征及酸雨成因进行了分析。结果表明,泰州市酸雨出现频率高,5年来降水pH均值均<5.6,降水酸度和酸雨出现频率无明显变化;降水中化学成分以SO42-为主,NO3-质量浓度值呈上升趋势;酸雨出现频率的季节变化规律为:冬、春季>秋季>夏季,与SO2在不同季节质量浓度变化规律较一致;酸雨的形成可能受本地大气污染物和异地大气污染物的共同影响;酸性降水的形成与气象条件有关。     

深圳市酸雨变化规律及成因

分析了深圳市2000年-2009年降雨监测数据.结果表明:深圳市降水pH年均值＜5.6,一年中酸雨最严重的是7-9月;影响降水的主要离子是SO2-、Cl-、NO3-、Ca2+、NH4+和Na+.气象因素是影响深圳市降水酸度的重要因素之一.     

临安大气本底站酸雨污染变化特征与影响因素分析

利用临安大气本底站酸雨观测数据,研究临安大气本底站降水pH,酸雨发生频率的时间分布特征、变化趋势及其影响因素;借助后向轨迹分析法分析输送形势对临安大气本底站酸雨的影响。研究表明:最近6年间临安大气本底站降水pH各月均值均小于4.5,均达到强酸雨的程度;临安大气本底站的酸雨发生频率表现为夏季低、秋季高;1985—2009年临安大气本底站降水的年均pH全部达到酸雨程度。根据Daniel趋势检验,临安大气本底站年均降水pH总体上呈逐年下降的趋势。风速越小,酸雨出现频率就越高;降水pH受降水量的影响较大。临安大气本底站的酸雨与降水前的大气中SO2浓度存在负相关的关系。根据气团的来向与酸雨污染程度的关系分析,临安大气本底站的酸雨污染受到其北部地区和浙西地区的酸雨气体物输送的影响较大。临安大气本底站的酸雨污染特征已由原来的硫酸型转为硫酸型与硝酸型并重。     

2001—2018年浙江省酸雨变化特征及影响因素分析

利用2001—2018年浙江省32个城市酸雨观测资料,结合数理统计和GIS空间插值,分析了全省降水酸度变化、化学组分特征及其影响因素。研究结果表明,以2009年为拐点,浙江省酸雨污染呈先加重后减轻的趋势,降水酸度和酸雨率均得到显著改善。2009年后,轻酸雨城市的比例不断上升。至2018年,全省大部分城市均处于轻酸雨区,并有部分非酸雨城市出现。降水中的硫酸根离子浓度呈显著下降趋势,硝酸根离子浓度呈波动变化,但变化不显著。硫酸根离子与硝酸根离子的当量浓度比值呈显著下降趋势,由2002年的3.48降至2018年的1.35,酸雨类型由硫酸主导型向复合型转变。二氧化氮、硝酸根离子和可吸入颗粒物是影响降水pH的主要因素,氮氧化物对浙江省降水酸度的影响不断增大。因此,在加强区域硫氮协同控制的同时,着力加强氮氧化物深度减排是进一步改善浙江省酸雨状况的关键。     

南京市酸雨污染变化趋势分析

基于1991—2013年南京市降水监测数据,采用Spearman秩相关系数,分析了该市酸雨污染的变化情况,以及阴阳离子组分特征与变化趋势。结果表明,自1991年以来,南京市酸雨频率有所上升,降水p H值显著下降,酸雨污染有加重趋势;硫氧化物仍是该市降水酸化的主要因素,而其致酸作用逐年减弱,NO-3的致酸作用逐年加强;来源于化工行业的氯化物对降水的污染状况得以改善,来源于碱性颗粒物的钙对酸雨的中和作用逐年减弱。     

扬州地区酸雨现状及成因分析

根据2006年1月—2010年12月的酸雨监测数据,对扬州地区酸雨的变化规律和趋势进行了统计分析。结果表明:扬州地区酸雨主要集中在扬州市区与仪征城区,"十一五"期间,扬州市区酸雨呈逐年减少趋势,仪征城区大气污染严重,降水pH年均值均小于5.6,经评价扬州市区属于非酸雨区-较重酸雨区,仪征城区属于轻酸雨区-重酸雨区。高邮、江都、宝应城区从2007年起无酸雨出现。仪征城区酸雨主要是由燃煤型和燃油型混合空气污染造成的,近年来随着机动车拥有量的迅速增加,各种机动车排放的尾气已成为形成酸雨的重要原因,应引起重视。     

伊犁河谷大气酸沉降变化趋势

对2007—2014年伊犁河谷大气降水监测结果进行分析,结合伊犁河谷流域相对湿润、封闭的地形地貌和逆温气候资源特征与煤化工、煤电发展态势,类比预测了酸雨前体物的增加对伊犁河谷大气降水p H值变化趋势的影响。研究结果表明:目前伊犁河谷大气降水尚处于本底水平,城市人类活动对伊犁河谷大气降水酸雨前体物SO2、NOx的贡献高于郊区。伊犁河谷酸雨前体物SO2、NOx排放强度与大气降水硫酸盐和硝酸盐实际监测浓度相存在正相关性。类比同处于新疆干旱区乌鲁木齐市出现酸雨年度的情况,"十三五"期间,伊犁河谷大规模煤电、煤化工基地的建设,酸雨前体物排放量大幅增加,将会造成酸雨发生的风险。     

Modelling Temperature Trends in New Zealand

If global warming is accelerating, then one might expect temperatures for most stations to be accelerating and perhaps variability to be increasing. In this study, we examine 57 New Zealand temperature time series for evidence of non-linearity and changing variability. These correspond to time series for annual minima, annual means and annual maxima for 19 stations. Estimation is by an extended least-squares method. We find a surprising diversity of behaviour of these series – presumably reflecting their different geographic factors as well as series length. We give evidence of regions where temperatures are decreasing. For series where a linear trend is significant, it is downwards in about one third of the cases. This proportion was higher in the South Island, especially for series of minima. Where a non-linear trend is significant, temperatures are decelerating in about one half of the cases. The ratio of downward to upward trends is highest among annual maxima and South Island minima and smallest in annual means. Where a linear trend in the variability is significant, it is decreasing in 13 cases and increasing in 5 cases, although possibly this is partly due to poorer quality data last century. Where a non-linear trend in the variability is significant, variability is decelerating in about two thirds of the cases. The results are used to project upper and lower return levels of minima, means and maxima for each of the series to the year 2010.     

a study of the temporal variability of atrazine in private well water. part ii: analysis of data

In 1988, the Iowa Department of Natural Resources, along withthe University of Iowa, conducted the Statewide Rural WellWater Survey, commonly known as SWRL. A total of 686private rural drinking water wells was selected by use of aprobability sample and tested for pesticides and nitrate. A subsetof these wells, the 10% repeat wells, were additionally sampledin October, 1990 and June, 1991. Starting in November, 1991,the University of Iowa, with sponsorship from the United StatesEnvironmental Protection Agency, revisited the 10% repeat wellsto begin a study of the temporal variability of atrazine and nitratein wells. Other wells, which had originally tested positive foratrazine in SWRL but were not in the 10% population, wereadded to the study population. Temporal sampling for a year-long period began in February of 1992 and concluded in Januaryof 1993. All wells were sampled monthly, a subset was sampledweekly, and a second subset was sampled for 14 day consecutiveperiods. Of the 67 wells in the 10% population tested monthly,7 (10.4%) tested positive for atrazine at least once during theyear, and 3 (4%) were positive each of the 12 months. Theaverage concentration in the 7 wells was 0.10 µg/L. Fornitrate, 15 (22%) wells in the 10% repeat population monthlysampling were above the Maximum Contaminant Level of 10 mg/L at least once. This paper, the second of two papers on thisstudy, describes the analysis of data from the survey. The firstpaper (Lorber et al., 1997) reviews the study design, theanalytical methodologies, and development of the data base.     

a study of the temporal variability of atrazine in private well water. part i: study design, implementation, and database development

In 1988, the Iowa Department of Natural Resources, along withthe University of Iowa conducted the Statewide Rural WellWater Survey, commonly known as SWRL. A total of 686private rural drinking water wells was selected by use of aprobability sample and tested for pesticides and nitrates. Sixty-eight of these wells, the 10% repeat wells, were additionallysampled in October, 1990 and June, 1991. Starting inNovember, 1991, the University of Iowa, with sponsorshipfrom the United States Environmental Protection Agency,revisited these wells to begin a study of the temporalvariability of atrazine and nitrates in wells. Other wells, whichhad originally tested positive for atrazine in SWRL but werenot in the 10% repeat population, were added to the studypopulation. Temporal sampling for a year-long period beganin February of 1992 and concluded in January of 1993. Allwells were sampled monthly, one subset was sampled weekly,and a second subset was sampled for 14-day consecutiveperiods. Two unique aspects of this study were the use of animmunoassay technique to screen for triazines before gaschromatography/mass spectrometry (GC/MS) analysis andquantification of atrazine, and the use of well owners to samplethe wells. A total of 1771 samples from 83 wells are in thefinal data base for this study. This paper reviews the studydesign, the analytical methodologies, and development of thedata base. A companion paper (Pinsky et al., 1997) discussesthe analysis of the data from this survey.     

Variability in Voc Concentrations in an Urban Area of Delhi

The variability of pollutants is an important factor in determining human exposure to the chemicals. This study presents the result of investigation of variability of Volatile organic compounds (VOCs) in urban area of Delhi, capital of India. Fifteen locations, in five categories namely residential, commercial, industrial, traffic intersections and petrol pump were monitored for one year every month during peak hours in morning and evening. Measurement focused on target VOCs as defined by USEPA. Variability was divided into measurement, spatial, temporal and temporal–spatial interaction components. Temporal component along with temporal–spatial interaction were found to be the major contributors to the variability of measured VOC concentrations. Need of continuous monitoring to capture short–term peak concentration and averages is evident.     

EMAP Overview: Objectives, Approaches, and Achievements

This paper summarizes the recommendations from the Intergovernmental Panel on Climate Change (IPCC) Workshop on Adaptation to Climate Variability and Change convened in Costa Rica in 1998. Specifically, this paper also summarizes the adaptive management science issues and, in many cases, sectoral options. The Workshop, organized by Canada and Costa Rica, involved more than 200 experts and focused on adaptation science, adaptive management and adaptation options for climate variability and change.     

城市河流水质参数空间变异性研究——以苏南某市为例

基于现场的采样数据,结合河流自身特点,应用地质统计学的理论和方法分析了苏南某城市河流水质参数的空间变异规律及其原因。研究结果表明,根据变差函数模型分析,发现研究区河流3个水质参数在一定范围内存在空间相关性;研究区河流的CODMn呈现中南部较高,其他部位相对均匀的趋势,CODMn的空间变异性主要是由居民的日常活动及河道的自身特点引起;研究区河流的TP和NH3-N含量严重超标,水体富营养化程度严重。TP和NH3-N的空间变异性相似,含量较高区域集中在研究区的西南部、东南部和东北部,其空间变异性主要由工业活动和居民日常生活共同作用引起,其中工业活动占主导作用。     

Assessment of spatial variability in some soil properties as related to soil salinity and alkalinity in Bafra plain in northern Turkey

The objectives of this study were to assess the variability in soil properties affecting salinity and alkalinity, and to analyze spatial distribution patterns of salinity (EC) and alkalinity (ESP) in the plain, which was used irrigation agriculture with low quality waters. Soil samples were collected from 0–30cm, 30–60cm, 60–90cm and 90–120cm soil depths at 60 sampling sites. Soil pH had the minimum variability, and hydraulic conductivity (Ks) had the maximum variability at all depths. The mean values of pH, EC, ESP and Ks increased while the mean values of CEC decreased with soil depth. Values pH, EC and ESP were generally high in the east and northeastern sides. Soil properties indicated moderate to strong spatial dependence. ESP and pH were moderately spatially dependent for three of the four depths, EC exhibited moderate spatial dependence for one of the four depths, CEC had a moderate spatial dependence at all depths, and Ks exhibited a strong spatial dependence. EC, CEC, and ESP were considerably variable in small distances. The spatial variability in small distances of EC, CEC, pH and ESP generally increased with depth. All geostatistical range values were greater than 1230m. It was inferred that the strong spatial dependency of soil properties would be resulted in extrinsic factors such as ground water level, drainage, irrigation systems and microtopography.     

Seasonal Variability of Heavy Metals in Surface Sediment of Lake Sapanca, Turkey

Lake Sapanca is exposed to heavy urbanization and industrialization because of its natural beauty and its proximity to the metropolitan İstanbul, Turkey. In this study, it was aimed to investigate seasonal changes of some heavy metals (Pb, Cr, Cu, Mn, Ni, Zn and Cd) concentration of surface sediment. Nine different stations were chosen as sampling points. Samples were taken every three months and the seasonal and annual average concentration of the elements were determined. Seasonal highest values of heavy metals were observed as follows; Cr, Cu, Mn, Ni and Zn in Summer, Cd in Autumn. There was no seasonal difference for Pb, Cr and Cd. It seems that Lake Sapanca has not been polluted yet. However, it was found that Cu and Ni concentrations in surface sediment exceed lowest effect level.     

Uncertainty in watershed response predictions induced by spatial variability of precipitation

Negligence to consider the spatial variability of rainfall could result in serious errors in model outputs. The objective of this study was to examine the uncertainty of both runoff and pollutant transport predictions due to the input errors of rainfall. This study used synthetic data to represent the “true” rainfall pattern, instead of interpolated precipitation. It was conducted on a synthetic case area having a total area of 20 km² with ten subbasins. Each subbasin has one rainfall gauge with synthetic precipitation records. Six rainfall storms with varied spatial distribution were generated. The average rainfall was obtained from all of the ten gauges by the arithmetic average method. The input errors of rainfall were induced by the difference between the actual rainfall pattern and estimated average rainfall. The results show that spatial variability of rainfall can cause uncertainty in modeling outputs of hydrologic, which would be transport to pollutant export predictions, when uniformity of rainfall is assumed. Since rainfall is essential information for predicting watershed responses, it is important to consider the properties of rainfall, particularly spatial rainfall variability, in the application of hydrologic and water quality models.     

小尺度滴灌棉田土壤硝态氮空间异质性研究

以1 m×0.8 m网格布点采集的土壤样为研究对象,从统计特征值、半方差函数和等直线图几个方面,对比分析3个时期土壤硝态氮养分的空间和时间变异特性。结果表明,各时期的变异系数受棉花的生长、田间作业影响较大。播前和收获期土壤硝态氮的空间结构符合球状模型,初花期则为线性模型,表明硝态氮含量变异是结构性与随机性共同作用的结果。硝态氮的空间变异性播前主要受结构因素影响;初花期主要受随机因素影响;收获后硝态氮含量的空间异质性变化人为因素大于结构因素。