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991.
Size distributions of ambient air particles and enrichment factor analyses of metallic elements at Taichung Harbor near the Taiwan Strait 总被引:2,自引:0,他引:2
Guor-Cheng Fang Yuh-Shen Wu Shih-Yu Chang Shih-Han Huang Jui-Yeh Rau 《Atmospheric Research》2006,81(4):320-333
This work attempts to characterize metallic elements associated with atmospheric particulate matter on a dry deposition plate, a TE-PUF high-volume air sampler and a universal air sampler. Dry deposition fluxes of particulates and concentrations of total suspended particulate, fine (PM2.5) and coarse (PM2.5–10) particulate matters were collected at Taichung harbor sampling sites from August 2004 to January 2005. Chemical analyses of metallic elements were made using a flame atomic absorption spectrophotometer coupled with hollow cathode lamps. Concentrations of metal elements in the forms of coarse particles and fine particles as well as the coarse/fine particulate ratios were presented. Statistical methods such as correlation analysis, principal component analysis and enrichment factor analysis were performed to compare the chemical components and identify possible emission sources at the sampling sites. Metallic elements of Cu, Zn, Pb, Cr, Ni and Mg had higher EFcrust ratios in winter and spring than in summer and autumn. Diurnal and nocturnal variations of metallic element concentrations in fine and coarse particles were also discussed. 相似文献
992.
Parameterization of the thermal impacts of sub-grid orography on numerical modeling of the surface energy budget over East Asia 总被引:4,自引:0,他引:4
Summary A parameterization scheme for the thermal effects of subgrid scale orography is incorporated into a regional climate model
(developed at Nanjing University) and its impact on modeling of the surface energy budget over East Asia is evaluated. This
scheme includes the effect of terrain slope and orientation on the computation of solar and infrared radiation fluxes at the
surface, as well as the surface sensible and latent heat fluxes. Calculations show that subgrid terrain parameters alter the
diurnal cycle and horizontal distributions of surface energy budget components. This effect becomes more significant with
increased terrain slope, especially in winter. Due to the inclusion of the subgrid topography, the surface area of a model
grid box changes over complex terrain areas. Numerical experiments, with and without the subgrid scale topography scheme,
show that the parameterization scheme of subgrid scale topography modifies the distribution of the surface energy budget and
surface temperature around the Tibetan Plateau. Comparisons with observations indicate that the subgrid topography scheme,
implemented in the climate model, reproduces the observed detailed spatial temperature structures at the eastern edge of the
Tibetan Plateau and reduces the tendency to overestimate precipitation along the southern coastal areas of China in summer. 相似文献
993.
In this work, we have investigated the evolution of the summer air–sea interaction in the North Atlantic Ocean and the physical
processes involved using reanalysis data and model simulation. It is found that an atmosphere disturbance over the North Atlantic
Ocean in the preceding winter favors the build-up of a North Atlantic horseshoe-like sea surface temperature anomaly (SSTA)
pattern in the summer through modifying the northeast trade winds and changing ocean upwelling and downwelling. The changed
ocean condition (SSTA, upwelling, and downwelling) further intensifies the atmosphere disturbance as a positive feedback.
The thermal advection of the atmosphere disturbance weakens the SSTA pattern in the following autumn and winter. The anomalous
circulation associated with the air–sea interaction in the observations is characterized by a barotropic structure in the
middle and high latitudes of the North Atlantic Ocean. The baroclinic component is enhanced in the model simulation, particularly
in the seasons from summer to winter. The life cycle of the air–sea interaction is about 1 year in both the observations and
simulations. 相似文献
994.
煤层陷落柱高分辨率地震探测技术 总被引:2,自引:0,他引:2
在华北、华东及西北地区近20多个煤田的石炭二叠系中,普遍存在着因煤系地层基底厚层灰岩古岩溶塌陷形成的煤层陷落柱,尤以山西省西山及汾河沿岸的煤田、河北省太行山中段的煤田更为普遍。煤层陷落柱发育形态分为圆锥形、筒形、斜塔形、不规则形等特点,应用高分辩地震勘探技术,根据陷落柱发育区反射波同相轴中断、扭曲、能量变弱、连续性变差、分叉合并或圈闭、产状突变等特征,可有效地探测其空间位置及形态。 相似文献
995.
996.
云南金平白马寨铜镍硫化物矿床含矿岩体为侵位在奥陶系砂页岩的镁铁-超镁铁环状杂岩体。从岩体核心到边缘依次出现橄榄岩—橄榄辉石岩—辉石岩—辉长岩的岩相分带。该岩体的主量元素显示拉斑玄武岩岩浆分异演化的趋势。REE显示富集LREE的配分模式,具明显的Eu异常。微量元素蛛网图显示明显的Ta、Nb、Ti及P的负异常。具有高(87Sr/86Sr)i(0.710974~0.722667)和低εNd(t)(-13.17~-12.09)的特征。微量元素和同位素地球化学证据表明,岩浆源于俯冲地壳物质改造的富集地幔,岩浆上升过程中遭受了一定的地壳物质混染。岩体可能是在弧后拉张的构造环境中形成。 相似文献
997.
Distribution and Geochemical Implication of Aromatic Hydrocarbons across the Meishan Permian-Triassic Boundary 总被引:5,自引:0,他引:5
INTRODUCTIONThe Permian-Triassic ( Tr/P) boundary , datedto be (251 .4±0 .3) Ma ago ,is marked by the mostdrastic mass extinction of organisms in the Phanero-zoic .In order to explore the pattern and the cause ofthe mass extinction,extensive research has been fo-cused on biostratigraphy , isotopic chronostratigra-phy , event stratigraphy , ecostratigraphy and se-quence stratigraphy (Payne et al .,2004 ; Reichowetal .,2002 ; Yin et al .,2001 ;Jin et al .,2000 ;Zhanget al .,1996 ,1995 ;… 相似文献
998.
1000.
Recent advances in the study of nonlinear atmospheric and climate dynamics in China (2003 2006) are briefly reviewed. Major achievements in the following eight areas are covered: nonlinear error dynamics and predictability; nonlinear analysis of observational data; eddy-forced envelope Rossby soliton theory; sensitivity and stability of the ocean's thermohaline circulation; nonlinear wave dynamics; nonlinear analysis on fluctuations in the atmospheric boundary layer; the basic structures of atmospheric motions; some applications of variational methods. 相似文献