On the variability and correlation of surface ozone and carbon monoxide observed in Hong Kong using trajectory and regression analyses   总被引：3，自引：0，他引：3  

WANG Tijian  K. S. LAM  C. W. TSANG  S. C. KOT 《大气科学进展》2004,21(1):141-152

This paper investigates, the variability and correlation of surface ozone (Os) and carbon monoxide (CO) observed at Cape D'Aguilar in Hong Kong from 1 January 1994 to 31 December 1995. Statistical analysis shows that the average O3 and CO mixing ratios during the two years are 32±17ppbv and 305±191 ppbv, respectively. The O3/CO ratio ranges from 0.05 to 0.6 ppbv/ppbv with its frequency peaking at 0.15. The raw dataset is divided into six groups using backward trajectory and cluster analyses. For data assigned to the same trajectory type, three groups are further sorted out based on CO and NOX mixing ratios. The correlation coefficients and slopes of O3/CO for the 18 groups are calculated using linear regression analysis. Finally, five kinds of air masses with different chemical features are identified: continental background (CB), marine background (MB), regional polluted continental (RPC), perturbed marine (P*M), and local polluted (LP) air masses. Further studies indicate that O3 and CO in the conti  相似文献   

Thermal History of the Horoman Peridotite Complex: A Record of Thermal Perturbation in the Lithospheric Mantle   总被引：1，自引：0，他引：1  

OZAWA  KAZUHITO 《Journal of Petrology》2004,45(2):253-273

The ascent history of the Horoman peridotite complex, Hokkaido,northern Japan, is revised on the basis of a detailed studyof large ortho- and clinopyroxene grains 1 cm in size (megacrysts)in the Upper Zone of the complex. The orthopyroxene megacrystsexhibit distinctive M-shaped Al zoning patterns, which werenot observed in porphyroclastic grains less than 5 mm in sizedescribed in previous studies. Moreover, the Al and Ca contentsof the cores of the orthopyroxene megacrysts are lower thanthose of the porphyroclasts. The Upper Zone is inferred to haveresided not only at a higher temperature than previously suggestedbut also at a higher pressure (1070°C, 2·3 GPa) thanthe Lower Zone (950°C, 1·9 GPa), in the garnet stabilityfield, before the ascent of the two zones. The Horoman complexprobably represents a 12 ± 5 km thick section of lithosphericmantle with an 10 ± 8°C/km vertical thermal gradient.The current thickness of the Horoman complex is 3 km, whichis a result of shortening of the lithospheric mantle by 0·25± 0·1 during its ascent. The Upper Zone appearsto have experienced a heating event during its ascent throughthe spinel stability field, with a peak temperature as highas 1200°C. The effect of heating decreases continuouslytowards the base of the complex, and the lowermost part of theLower Zone underwent very minor heating at a pressure higherthan 0·5 GPa. The uplift and associated deformation,as well as heating, was probably driven by the ascent of a hotasthenospheric upper-mantle diapir into the Horoman lithosphere. KEY WORDS: Horoman; P–T trajectory; thermal history; Al diffusion in pyroxene; geothermobarometry  相似文献   

Seasonal trend of particulate PAHs at Gosan, a background site in Korea between 2001 and 2002 and major factors affecting their levels     

Ji Yi Lee  Yong Pyo Kim  Chang-Hee Kang  Young Sung Ghim   《Atmospheric Research》2006,82(3-4):680

The concentrations of particulate Polycyclic aromatic hydrocarbons (PAHs) were measured at Gosan, a background site in Korea for 1 year between November 2001 and November 2002. The total concentrations of 14 PAH compounds at Gosan were between 0.52 and 14.76 ng m^− 3 and about 3–15 times higher than those at other rural or remote sites in the world. Seasonal trend was observed for particulate PAHs concentrations at Gosan with higher levels during heating season due to increased fossil fuel usage and the movement of air parcels from Asian continent. Principal component factor analysis (PCF) for PAHs showed three factors; combination of coal combustion and vehicular emission, natural gas combustion, and unidentified one. However, PCF for the combined data of PAHs, inorganic ions, and elements revealed that the unidentified factor consists of crustal species, sea salts, and four PAH compounds. Thus, this factor is thought to be transport of crustal species with organics from combustion sources. The major variables which determine the sources of PAHs are the heating season and the movement of air parcels from Asian continent.  相似文献   

Interface Roughness by Optical Coherence MicroscopyZHU Yong-kai~(1),LI Ji-nian~(1)     

Systems Enginee 《地球空间信息科学学报》2006,(2)

IntroductionIf let roadway entities be denoted by arcs and in-tersections be denoted by nodes, then a road net-work can be represented with node-arc model. Be-cause the designation of nodes can be determinedby arcs according to the definition of node-arc …  相似文献   

ISENTROPIC TRAJECTORY ANALYSES OF POLLUTANT TRANSPORT IN NORTHEAST ASIA-INFLUENCE ON CHINA FROM NEIGHBORING COUNTRIES     

盛裴轩  毛节泰 《Acta Meteorologica Sinica》1998,(2)

The transport of air pollutants from several big cities in the north of China and theneighboring countries is researched by using the isentropic trajectory model. The trajectories arecalculated twice daily for the cities in January, April. July and October for the period of 1992-1994. The statistical method has been used to deal with trajectory dots at intervals of 30 min forthe forward and backward trajectories during 0-24 h and 24-48 h. The probability distributiondiagrams of trajectory show clearly the ensemble properties of isentropic trajectories for each cityand the dominant transport directions of pollutants. They possess notable seasonal variations. Theforward trajectory areas of the Ulaan Baatar in Mongolia can spread over North China. and thoseof the Chita in Russia can influence Northeast China except in summer. In July the forwardtrajectory of Pyongyang and Seoul can extend northward to the boundaries of China.  相似文献   

Regional Sources of Methyl Chloride, Chloroform and Dichloromethane Identified from AGAGE Observations at Cape Grim, Tasmania, 1998–2000     

M. L. Cox  G. A. Sturrock  P. J. Fraser  S. T. Siems  P. B. Krummel  S. O'Doherty 《Journal of Atmospheric Chemistry》2003,45(1):79-99

There are large uncertainties in identifying and quantifying the natural and anthropogenic sources of chloromethanes – methyl chloride (CH₃Cl), chloroform (CHCl₃) and dichloromethane (CH₂Cl₂), which are responsible for about 15% of the total chlorine in the stratosphere. We report two years of in situ observations of these species from the AGAGE (Advanced Global Atmospheric Gas Experiment) program at Cape Grim, Tasmania (41° S, 145° E). The average background levels of CH₃Cl, CHCl₃ and CH₂Cl₂ during 1998–2000 were 551± 8, 6.3± 0.2 and 8.9± 0.2 ppt (dry air mole fractions expressed in parts per 10¹²) respectively, with a two-year average amplitude of the seasonal cycles in background air of 25, 1.1 and 1.5 ppt respectively. The CH₃Cl and CHCl₃ records at Cape Grim show clear episodes of elevated mixing ratios up to 1300 ppt and 55 ppt respectively, which are highly correlated, suggesting common source(s). Trajectory analyses show that the sources of CH₃Cl and CHCl₃ that are responsible for these elevated observations are located in coastal-terrestrial and/or coastal-seawater regions in Tasmania and the south-eastern Australian mainland. Elevated levels of CH₂Cl₂ (up to 70 ppt above background) are associated mainly with emissions from the Melbourne/Port Phillip region, a large urban/industrial complex (population 3.5 million) 300 km north of Cape Grim.Now at the Centre for Atmospheric ChemistryNow at School of Environmental Sciences  相似文献   

PIV在横流中的湍射流实验研究中的应用   总被引：1，自引：4，他引：1       下载免费PDF全文

姜国强  张晓元  李炜 《水科学进展》2002,13(5):588-593

利用粒子图象测速技术(PIV),对横流中具有复杂结构流动的湍射流进行了详细观测.实验给出了射流沿程发展情况和由断面最大流速连线形成的轨迹线方程,研究中还发现射流尾迹区中的大尺度结构与圆柱绕流有很大区别.  相似文献   

南京北郊污染物来源及跨区域输送过程研究          下载免费PDF全文

黄乾  王海波 《大气科学学报》2019,42(4):531-541

利用全国空气质量指数(Air Quality Index,AQI)、PM_(2.5)地面观测数据、全球数据同化系统GDAS数据和FNL再分析气象资料,研究了2015/2016年冬季南京北郊空气质量变化特征以及环境输送条件和污染物源区。结果表明:以AQI为代表的冬季江淮地区污染程度存在3种典型的污染物跨区域输送路径—西北路径、北方路径和西南路径。西北路径通常发生在蒙古高压较强,且处于平均位置时刻,南京北郊上空有冷平流,不利于污染物扩散;北方路径对应蒙古高压弱,东北附近为弱高压控制,偏北气流将污染物带至南京北郊,如跨海洋,则污染减弱;西南路径对应南京北郊为边界层内反气旋式环流中心,下沉气流十分不利于污染物扩散。影响南京北郊污染的潜在源区主要分布在河北南部、山东西部、河南南部、安徽东部和湖北西部。河北省是重要的污染源区,河北南部和山东西部污染物通过北方路径输送至南京北郊,因此北方路径虽发生污染概率少于其他两种,却是形成南京北郊严重污染的重要路径。河南南部污染物通过西北路径输送。安徽和湖北污染物通过西南路径输送。定量分析表明,平流输送是南京北郊重度污染的重要原因,近地层风速对AQI的平流输送占AQI变化的贡献率超过70%,甚至可达85%。  相似文献   

人影高炮作业落区的一种判定方法     

马鑫鑫  李昊  丁建芳  杨敏  田万顺 《内蒙古气象》2011,(4):57-59

提出了人影高炮弹丸轨迹的运动方程,根据方程计算理论弹丸落点并得出安全区外扩的误差范围。针对人影高炮作业射界设定安全区的情况,提出落点位于安全区内外的判定方法,从而在理论上给出判断人影高炮作业安全性的问题。  相似文献   

Moisture source diagnostics and isotope characteristics for precipitation in east Hungary: implications for their relationship   总被引：1，自引：0，他引：1  

Emese Bottyán  Tamás Weidinger  László Haszpra  Krisztina Kármán 《水文科学杂志》2017,62(12):2049-2060

Knowledge relating to the relationship between the characteristics of precipitation and sources of moisture is essential to improve our understanding of the global water cycle. This study presents the first quantitative estimation of the moisture source regions combined with stable isotope analyses for precipitation at K-puszta, east Hungary. The contributions of the following moisture sources were diagnosed according to the sector analysis of 4-day backward trajectories together with the calculation of evaporation and precipitation fluxes based on the specific humidity: Mediterranean region (57.0%), local moisture (14.8%), Atlantic region (14.2%), Northern Europe (7.4%) and Eastern Europe (6.6%). The δD and δ¹⁸O values of daily precipitation were measured and the deuterium excess (d-excess) was calculated. The d-excess showed systematic differences among the marine sources, reflecting the characteristics of the moisture source area. The results suggest that the stable isotope composition of precipitation preserves information regarding the origin of the water vapour.  相似文献