甘肃北山—河西走廊—祁连山区域地下水循环模式     

董艳辉  符韵梅  王礼恒  王驹  张倩  宗自华  周志超 《地质科技情报》2022,41(1):79-89

山区地下水流动受到区域气候条件、地形地貌、地质构造等因素共同控制,限于资料有限,其流动模式与控制机理尚不清晰.特别是地处甘肃北山的高放废物地质处置库预选区、河西走廊以及祁连山北麓区域地下水的流动模式,直接决定了处置库在万年时间尺度上的安全性.基于区域遥感构造解译、地质构造演化分析、地球物理勘探以及水文地质钻探,获取了典...  相似文献   

CCD photometry of five X-ray selected BL Lacertae objects     

L. Ma  G. Z. Xie  T. F. Yi  S. B. Zhou  K. H. Li  X. Zhang  H. Dai 《Astrophysics and Space Science》2010,327(1):35-58

We present the results of the monitoring of a sample of 5 HBLs in the B, V and R bands during 2003–2008. All sources in our monitoring project show significant rapid optical variations, except 1ES 1959+650, however; for 1ES 1959+650, the gamma-ray variability on a timescale of ～7 hours has been observed by Holder et al. (Astrophys. J. 583:L9, 2003). Using these variability timescales, we estimate the black hole masses for each source with the Kerr black hole theory.  相似文献   

Solar Intranetwork Magnetic Elements: Evolution and Lifetime     

G. P. Zhou  J. X. Wang  C. L. Jin 《Solar physics》2010,267(1):63-73

Based on Hinode SOT/NFI observations with greatly improved spatial and temporal resolution and polarization sensitivity, the lifestory of the intranetwork (IN) magnetic elements are explored in a solar quiet region. A total of 2282 IN elements are followed from their appearance to disappearance and their fluxes measured. By tracing individual IN elements their lifetimes are obtained, which fall in the range from 1 to 20 min. The average lifetime is 2.9±2.0 min. The observed lifetime distribution is well represented by an exponential function. Therefore, the e-fold characteristic lifetime is determined by a least-square fitting to the observations, which is 2.1±0.3 min. The lifetime of IN elements is correlated closely with their flux. The evolution of IN elements is described according to the forms of their birth and disappearance. Based on the lifetime and flux obtained from the new observations, it is estimated that the IN elements have the capacity of heating the corona with a power of 2.1×10²⁸ erg s⁻¹ for the whole Sun.  相似文献   

Observed winds,turbulence, and dispersion in built-up downtown areas of Oklahoma City and Manhattan   总被引：2，自引：2，他引：0  

Steven Hanna  John White  Ying Zhou 《Boundary-Layer Meteorology》2007,125(3):441-468

Wind and tracer data from the Oklahoma City Joint Urban 2003 (JU2003) and the Manhattan Madison Square Garden 2005 (MSG05) urban field experiments are being analyzed to aid in understanding air flow and dispersion near street-level in built-up downtown areas. The mean winds are separately calculated for groups of anemometers having similar exposures such as “near street level” and “on building top”. Several general results are found, such as the scalar wind speed at street level is about 1/3 of that at building top. Turbulent standard deviations of wind speed components and temperature, and vertical fluxes of momentum and sensible heat, are calculated from sonic anemometers near street level at 20 locations in JU2003 and five locations in MSG05, and from two rooftop locations in MSG05. The turbulence observations are consistent with observations in the literature at other cities, although the JU2003 and MSG05 data are unique in that many data are available near street level. For example, it is found that the local (i.e., at the measuring height) averages about 1.5 and the local averages about 0.25 in the two cities, where is the standard deviation of vertical velocity fluctuations, is the friction velocity, and u is the wind speed. The ratio of temperature fluctuations to temperature scale, , averages about −3 in both cities, consistent with similarity theory for slightly unstable conditions, where is the standard deviation of temperature fluctuations, and is the temperature scale. The calculated Obukhov length, L, is also consistent with slightly unstable conditions near street level, even at night during JU2003. The SF₆ tracer concentration observations from JU2003 are analyzed. Values of for the continuous releases are calculated for each release and arc distance, where is the 30-min average arc maximum concentration, Q is the continuous source emission rate, and u is the spatial-averaged wind speed in the downtown area. The basic characteristics of the JU2003 plot of averaged agree reasonably well with similar plots for other urban experiments in Salt Lake City and London (i.e., at . A is found to be about 3 during the day and about 10 during the night.  相似文献   

德州气候变化与建筑物防腐   总被引：2，自引：0，他引：2  

石慧兰  周圣军  陈松 《气象科技》2007,35(6):882-885

利用德州11县市1951～2005年温度、降水资料,计算气候干燥度,1981～2005年与1951～1980年相比全市干燥度由1.45增大到1.64,已由原来的半湿润气候变化为半干旱气候。各县市降水量呈减少趋势,平均每10年减少19.64mm;气温呈上升趋势,平均每10年升高0.11℃,冬季升高0.30℃,冬季增温显著,北部县市已由原来的冰冻区变化为微冻区,全市均为微冻区。由于气候条件变化,相应场地环境类别与腐蚀介质指标的调整系数标准应作调整改变,场地环境类别由Ⅱ类转变为Ⅰ类,腐蚀介质指标的调整系数均取0.9。  相似文献   

应用KDD技术分析气象地质灾害与降水的关系     

彭贵芬  段旭  舒康宁  周毅 《气象科技》2007,35(2):252-257

应用人工智能技术——数据库中知识发现(KDD)技术,分析研究发生在云南省境内造成重大损失的气象地质灾害的发生与当日及前期降水的关系。结果表明,绝大多数气象地质灾害都是由强降水诱发的,云南气象地质灾害与发生当日及前期降水的关系主要有3种类型,即暴雨诱发型、多日中大雨诱发型和连阴雨诱发型。所得到的云南气象地质灾害与当日及前期降水的定量关系,为云南地质灾害的气象监测、预报模式的建立提供了依据。  相似文献   

High-pressure granulite from Western Kunlun,northwestern China: Its metamorphic evolution,zircon SHRIMP U-Pb ages and tectonic implication   总被引：1，自引：0，他引：1  

QU JunFeng  ZHANG LiFei  AI YongLiang  L Zeng  WANG JianPing  ZHOU Hui & WANG ShiYan MOE Key Laboratory of Orogenic Belts  Crustal Evolution  School of Earth  Space Science  Peking University  Beijing  China  Henan Polytechnic University  Jiaozuo  China  Geological Survey of Henan Province  Zhengzhou  China 《中国科学D辑(英文版)》2007,50(7):961-971

High-pressure mafic granulites occurring as lenticular bodies within garnet-amphibolites in Kangxiwar Fault have been first reported in this paper. The P-T conditions of two metamorphic stages were ob-tained using calibrated geothermal barometers and ThermoCalc Program. The peak metamorphic con-dition of these high-pressure granulites is about 760―820℃,1.0―1.2 GPa and the retrograde meta-morphic condition is about 620―720℃,0.7―0.8 GPa. The petrological studies show that they have a near-isobaric cooling P-T...  相似文献   

Quantitative assessment of the spatial distribution of 239+240Pu inventory derived from global fallout in soils from Asia and Europe     

Cao  Liguo  Zhou  Zhengchao  Wang  Ning  Xiao  Shun 《地理学报(英文版)》2022,32(4):605-616

Journal of Geographical Sciences - Due to the atmospheric nuclear weapon tests carried out, terrestrial environments have been extensively contaminated by global fallout of plutonium (Pu)...  相似文献   

Geochemical characteristics,cooling history and mineralization significance of Zhangtiantang pluton in South Jiangxi Province,P.R. China   总被引：1，自引：0，他引：1  

Jianren Mao  Zilong Li  Xilin Zhao  Jie Zhou  Haimin Ye  Qitao Zeng 《中国地球化学学报》2010,29(1):53-64

The zircon SHRIMP dating of the Zhangtiantang granite gave an age of 159±7 Ma., which shows that the granite was produced at the early Late Jurassic. The Ar-Ar plateau ages of biotite and K-feldspar from the Zhangtiantang pluton are 153.2±1.1 Ma and 135.8±1.2 Ma, respectively. The Ar-Ar anti-isochrone ages of biotite and K-feldspar are 152.5±1.7Ma and 135.4±2.7Ma, respectively. The ages represent the isotopic closure ages of minerals in the pluton. The Zhangtiantang granites are regarded as peraluminous crust-derived type granites to possess the typical geochemical characteristics of calc-alkaline rocks on continental margin, with enriched Si, K, Al (average value of A/CNK as 1.18), HREE, Rb, U, and Th, heavily depleted V, Cr, Co, Ni, Ti, Nb-Ta, Zr, Sr, P, and Ba, strongly negative Eu and common corundum normative (average value of C as 1.84). The εNd_(t) values of the Zhangtiantang granite are −5.84 to −7.79, and t _2DM values are 1.69 to 1.83 Ga, which indicates partial melting of continental-crust metamorphic sedimentary rocks during the Middle Proterozoic. The cooling history of the Zhangtiantang granitic pluton indicates that the cooling velocity of pluton was faster (about 67°C/Ma) from zircon (158 Ma) to biotite (152 Ma), and was slower (about12°C/Ma) from biotite (152.5 Ma) to K-feldspar (135.8 Ma). It can be deduced that the temporal gap (about 10 Ma) between the granite formmation and W-Sn mineralization in South China may be related to ordinary magma-hydrothermal processes by the variational cooling curve of the pluton. The Zhangtiantang pluton was formed in a compressive setting, with differentiation evolution and mineralization occurring in a relative relaxation setting.  相似文献   

Source apportionment and distribution of atmospheric mercury in urban Beijing,China     

Xiaocheng Zhou  Jianguo Du  Chuanyuan Wang  Sujian Liu 《中国地球化学学报》2010,29(2):182-190

The concentration of gaseous elemental mercury (GEM) in the atmosphere of urban Beijing was measured from October 2003 to September 2004 to investigate the origins and spatial-temporal variations of atmospheric Hg. The mean value of Hg concentration is 17.1 ng·m-3 (n=653). The atmospheric Hg data showed spatial-temporal variations throughout the duration of our observation. The maximum GEM concentration (53.7 ng·m-3) was observed at Gucheng in the western area of urban Beijing. The GEM concentrations increased from the north to the south of the studied area, and were higher in winter than in summer. The highest and lowest monthly averages of GEM concentrations were measured to be 23.3 and 4.1 ng·m-3 in January and July, respectively. In addition, GEM concentrations are higher in the daytime than at night in Autumn and from 14 March to 15 April, but daily GEM variation showed an inverse pattern from 22 April to 22 May. In winter, two peak values of GEM concentrations occurred at 13:30 and 21:30. Daily variation of GEM concentrations in summer was the lowest in the four seasons. Mercury from coal combustion was estimated to be the main source of anthropogenic emissions in Beijing from October 2003 to September 2004. Additionally, Hg emission from natural gas burning was estimated to be another dominant source of atmospheric Hg in Beijing.  相似文献