Intercomparison of NO_x, SO_2, O_3, and Aromatic Hydrocarbons Measured by a Commercial DOAS System and Traditional Point Monitoring Techniques   总被引：1，自引：0，他引：1  

谢品华  刘文清  付强  王瑞斌  刘建国  魏庆农 《大气科学进展》2004,21(2)

A field-based Intercomparison study of a commercial Differential Optical Absorption Spectroscopy (DOAS) instrument (OPSIS AB, Sweden) and different point-sample monitoring techniques (PM, based on an air monitoring station, an air monitoring vehicle, and various chemical methods) was conducted in Beijing from October 1999 to January 2000. The mixing ratios of six trace gases including NO, NO2, SO2, O3, benzene, and toluene were monitored continuously during the four months. A good agreement between the DOAS and PM data was found for NO2 and SO2. However, the concentrations of benzene, toluene, and NO obtained by DOAS were significantly lower than those measured by the point monitors. The ozone levels monitored by the DOAS were generally higher than those measured by point monitors. These results may be attributed to a strong vertical gradient of the NO-O3-NO2 system and of the aromatics at the measurement site. Since the exact data evaluation algorithm is not revealed by the manufacturer of the DOAS sys  相似文献   

Numerical Simulation of Global Temperature Change during the 20th Century with the IAP／LASG GOALS Model   总被引：1，自引：0，他引：1  

MA Xiaoyan  GUO Yufu  SHI Guangyu  YU Yongqiang 《大气科学进展》2004,21(2):227-235

The IAP/LASG GOALS coupled model is used to simulate the climate change during the 20th century using historical greenhouse gases concentrations, the mass mixing ratio of sulfate aerosols simulated by a CTM model, and reconstruction of solar variability spanning the period 1900 to 1997. Four simulations, including a control simulation and three forcing simulations, are conducted. Comparison with the observational record for the period indicates that the three forcing experiments simulate reasonable temporal and spatial distributions of the temperature change. The global warming during the 20th century is caused mainly by increasing greenhouse gas concentration especially since the late 1980s; sulfate aerosols offset a portion of the global warming and the reduction of global temperature is up to about 0.11℃ over the century; additionally, the effect of solar variability is not negligible in the simulation of climate change over the 20th century.  相似文献   

安徽贵池地区二叠系孤峰组露头层序地层     

许卫  岳书仓  杜建国  杜森官  孙乘云 《地层学杂志》2004,28(2):137-141,147

依据实测地层剖面的详细研究,将二叠系孤峰组分为四个三级层序,每个三级层序跨时平均约1.25Ma,其高频变化表现为:海侵体系域的粒序变化主要表现为下粗上细的正粒序组构特征,总体表现为自下而上沉积水体由浅变深的退积型旋回;高位体系域的粒序变化主要表现为下粗上细的正粒序组构特征,总体表现为自下而上沉积水体由深变浅的进积型旋回。  相似文献   

粒度分组:提取古环境变化信息的一种有效方法   总被引：3，自引：0，他引：3  

李福春  谢昌仁  冯家毅  杨用钊 《地球化学》2004,33(5):477-481

对南京老虎山黄土-古土壤剖面全样和三个粒级组分(《2 μm、2～45μm和》45 μm)的Rb/Sr比值进行了系统研究.结果表明,Rb/Sr比值是衡量黄土和古土壤化学风化强度的良好地球化学指标;粒度分组是利用Rb/Sr比值研究古环境变化的有效方法.通过粒度分组,可以排除不同粒度组分之间由于Rb/Sr初始比值不同造成的互相干扰.《2 μm粒级的(Rb/Sr)-Sr反相关图的R2值最大(达0.97),说明该粒级指示化学风化作用的灵敏度最高,研究Rb/Sr比值这一地球化学指标最理想.  相似文献   

硫酸盐气溶胶辐射强迫的数值模拟研究   总被引：5，自引：0，他引：5  

马晓燕  石广玉  郭裕福  张立盛 《气候与环境研究》2004,9(3):454-464

利用IAP/LASG GOALS 4.0海气耦合模式,"显式"考虑了硫酸盐气溶胶的直接作用,并且引入德国马普气象研究所的三维浓度分布资料,模拟计算了硫酸盐气溶胶的辐射强迫.主要结果为:全球气溶胶年平均的辐射强迫为-0.29 W m-2,在IPCC TAR给定的范围内,空间分布上具有明显的地域性,几个大值地区分别为东亚、西欧和北美,它们的中心值均超过-1.5 W m-2,南美、澳大利亚以及非洲南部的辐射强迫介于-0.2～-0.4 W m-2之间,而海洋和偏远的大陆地区,则基本上不受人为硫酸盐气溶胶的影响;计算的东亚地区硫酸盐气溶胶的平均辐射强迫为-0.75 W m-2,约为全球平均的2.5倍,为北半球平均的1.6倍.文中还讨论了全球硫酸盐气溶胶对温室气体辐射强迫的减缓作用.  相似文献   

高放废物深地质处置库预选场址的古温度环境     

罗兴章  闵茂中郑正 王驹金远新  郭永海 《地质论评》2004,50(5):548-553

填隙矿物的流体包裹体研究与矿物的同位素地球化学研究可较好地揭示高放废物深地质处置库预选场址的深部热环境及古地下水热历史。中国高放废物深地质处置库第一个预选场深部花岗岩内填隙矿物的同位素、矿物学以及流体包裹体研究结果显示,甘肃北山地区花岗岩深部至少存在两种环境：浅部花岗岩(0～150m)填隙方解石的δ^18O=-18．2‰～-15．8‰(PDB),δ^13C=-9．5‰～-8．4‰(PDB),包裹体的均一温度(th)为140～160℃,包裹体的冰点温度为-2．5～-1．5℃,地下水可能以大气降水成因为主,且可能混合了盆地卤水并与花岗岩反应,形成温度、盐度(2％～5％,NaCleq)均较低的地下水;在350～550m区段内(深部花岗岩),其δ^18O值为-32．6‰～-17．6‰(PDB),δ^13C值为-10．5‰～-6．2‰(PDB),流体包裹体的均一温度较其上部的稍高,为160～190℃,而其冰点温度则较低,为-4～-3．2℃(盐度5％～8％,NaCleq),地下水类型为大气降水与盆地古卤水的混合,以大气降水为主。石英的氧同位素组成和计算的古地下水氧同位素组成则进一步表明,花岗岩深部(350～550m)也存在两种温度环境：较低温度(140～160℃)、较高盐度(5．5％～8％,NaCleq)的地下水;较高温度(220～240℃)、较低盐度(3％～5．5％,NaCleq)的地下水,其地下水类型为大气降水和与花岗岩平衡的卤水。  相似文献   

The response of runoff components and glacier mass balance to climate change for a glaciated high-mountainous catchment in the Tianshan Mountains     

Wang  Xiaoyan  Yang  Tao  Xu  Chong-Yu  Xiong  Lihua  Shi  Pengfei  Li  Zhenya 《Natural Hazards》2020,104(2):1239-1258

Natural Hazards - Glaciers are important freshwater storage systems in the Tianshan Mountains. Under the context of climate change, quantifying changes in glacier mass balance, the melt-season...  相似文献   

Non‐point source pollution modelling using Soil and Water Assessment Tool and its parameter sensitivity analysis in Xin'anjiang catchment,China          下载免费PDF全文

Xiaoyan Zhai  Yongyong Zhang  Xuelei Wang  Jun Xia  Tao Liang 《水文研究》2014,28(4):1627-1640

Non‐point source pollution is a key issue in integrated river basin management around the world and has resulted in water contamination, aquatic ecology deterioration and eutrophication. Xin'anjiang catchment is the key drinking water source area for Hangzhou City, China. A promising model (Soil and Water Assessment Tool) was applied to assess the non‐point source pollution and its effect on drinking water. Sensitivity analysis of model parameters was carried out using the Sequential Uncertainty Domain Parameter Fitting 2 sensitivity technique. Water discharge, sediment, total nitrogen and total phosphorus load processes from 2000 to 2010 were simulated, and the spatial distributions of non‐point source pollutants were evaluated at the catchment and administrative country levels. The results show that the hydrological parameters of the Soil and Water Assessment Tool were dominantly sensitive for non‐point source pollution simulation, including CN2, RCHRG_DP, ALPHA_BF, SOL_AWC, ESCO and SOL_K and the characteristic parameters of sub‐basins (viz. HRU_SLP and SLSUBBSN). Also, water quality parameters (viz. CH_EROD, NPERCO, RSDCO and PPERCO, PHOSKD, etc.) have a significant effect on nutrients. The model performance was very satisfactory, especially for runoff, sediment and total phosphorus simulation. The non‐point source pollutant load increased from 2001 to 2010 in the whole catchment. Total nitrogen load increased from 3428 tons (0.59 ton km^?2) to 7315 tons (1.25 ton km^?2), and total phosphorus load increased from 299 tons (0.05 ton km^?2) to 867 tons (0.15 ton km^?2). The contribution of rice land was the largest, accounting for nearly 95%, followed by tea garden (3.56%), winter wheat (1.37%), forest (0.07%) and grassland (0.02%). Moreover, She County and Xiuning County contributed more than half of the non‐point source pollutants. This study was expected to provide a method and reference for non‐point source pollution quantification and to support water quality management implementation in China. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Seasonal variations of deuterium and oxygen‐18 isotopes and their response to moisture source for precipitation events in the subtropical monsoon region          下载免费PDF全文

Huawu Wu  Xinping Zhang  Li Xiaoyan  Guang Li  Yimin Huang 《水文研究》2015,29(1):90-102

Deuterium and oxygen‐18 are common environmental tracers in water used to investigate hydrological processes such as evaporation and groundwater recharge, and to trace moisture source. In this study, we collected event precipitation from 01 January 2010 to 28 February 2011 at a site in Changsha, Yangtze River Basin to estimate the influence of moisture source and atmospheric conditions on stable isotope compositions. The local meteoric water line, established as δD = (8.45 ± 0.13) δ¹⁸O + (17.7 ± 0.9) (r² = 0.97, n = 189), had a higher slope and intercept than global meteoric water line. Temperature–δ¹⁸O exhibited complex correlations, with positive correlations during Nov.–Apr. superior to during Jun.–Sep., which was attributed to distinctive moisture sources, but vague the overall period; amount effect examined throughout the year. Linear regressions between δ¹⁸O and δD value in different precipitation event size classes revealed progressively decreasing slope and intercept values with decreasing precipitation amount and increasing vapour pressure deficit, indicating that small rainfall events (0–5 mm) were subject to secondary evaporation effects during rainwater descent. In contrast, snowfall and heavy precipitation events exhibited high slope and intercepts for the regression equation between δ¹⁸O and δD. High concentrations of heavy isotopes were associated with precipitation events sourced from remote westerly air masses, degenerated tropical marine air masses from the Bay of Bengal (BoB), and inland moisture in the pre‐monsoon period, as determined from backward trajectories assessed in the HYSPLIT model. Meanwhile, low concentrations of heavy isotopes were found to correspond with remote maritime moisture from BoB, the South China Sea, and the west Pacific at three different air pressures in summer monsoon and post‐monsoon using HYSPLIT and records of typhoon paths. These findings suggest that stable isotope compositions in precipitation events are closely associated with the meteorological conditions and respond sensitively to moisture source in subtropical monsoon climates. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Shrinkage and fragmentation of marshes in the West Songnen Plain,China, from 1954 to 2008 and its possible causes     

Zongming Wang  Ni Huang  Ling Luo  Xiaoyan Li  Chunying Ren  Kaishan Song  Jing Ming Chen 《International Journal of Applied Earth Observation and Geoinformation》2011

Agricultural development under climatic variations has resulted in substantial loss of marshes in the West Songnen Plain in the past decades. In this paper, the shrinkage and fragmentation process of marshes and its possible causes in the West Songnen Plain from 1954 to 2008 were explored using historical topographic maps and remote sensing data. Results indicated that the West Songnen Plain underwent considerable shrinkage and fragmentation of marshes in that same period. Marshes occupied 6404 km² in 1954, but this area has decreased by 74% in the past 54 years. The average annual decrease rate of marshes was 88 km² per year. Meanwhile, the number of marsh patches decreased from 1411 to 514, and the mean patch size decreased from 454 to 320 ha. Cropland and salinized wasteland were the two main land use types into which marshes were converted. During the same period, grassland decreased by 54%, cropland increased by 22%, and salinized wasteland expanded by 612%. A significant increase in air temperature and index of dryness was found in the study region, along with decreased precipitation, thereby affecting the marsh systems through the changing hydrological regimes. On the other hand, population, gross domestic product, and livestock number increased considerably as marshes shrank and became fragmented. Governmental policy changes played a key role in land use transformations in the study region.  相似文献