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91.
92.
柴达木盆地土壤盐渍化程度快速动态监测 总被引:1,自引:0,他引:1
针对柴达木盆地土壤盐渍化的时空变化问题,该文采用了反演土壤盐度指数的方法快速评估了该地区的盐渍化程度变化及其空间分布,并且选择2015年利用土壤采样方法获取标本验证SI在研究区的适用性,集成RS技术和GIS空间分析的优势,综合利用空间分析和时序分析技术对柴达木盆地2000-2015年的盐渍化程度和分布面积进行了时空变化分析.研究结果表明了 SI值在研究区的适用性,同时发现2000-2015年,柴达木盆地土壤盐渍化的面积和程度整体上均有明显降低趋势,尤其在重度盐渍化区域更为明显,但中、低度积盐面积,程度均有所增加.研究可以为柴达木盆地土壤盐渍化程度的快速评估提供参考. 相似文献
93.
The role of the Indonesian Throughflow(ITF) in the influence of the Indian Ocean Dipole(IOD) on ENSO is investigated using version 2 of the Parallel Ocean Program(POP2) ocean general circulation model. We demonstrate the results through sensitivity experiments on both positive and negative IOD events from observations and coupled general circulation model simulations. By shutting down the atmospheric bridge while maintaining the tropical oceanic channel, the IOD forcing is shown to influence the ENSO event in the following year, and the role of the ITF is emphasized. During positive IOD events,negative sea surface height anomalies(SSHAs) occur in the eastern Indian Ocean, indicating the existence of upwelling.These upwelling anomalies pass through the Indonesian seas and enter the western tropical Pacific, resulting in cold anomalies there. These cold temperature anomalies further propagate to the eastern equatorial Pacific, and ultimately induce a La Nia-like mode in the following year. In contrast, during negative IOD events, positive SSHAs are established in the eastern Indian Ocean, leading to downwelling anomalies that can also propagate into the subsurface of the western Pacific Ocean and travel further eastward. These downwelling anomalies induce negative ITF transport anomalies, and an El Nio-like mode in the tropical eastern Pacific Ocean that persists into the following year. The effects of negative and positive IOD events on ENSO via the ITF are symmetric. Finally, we also estimate the contribution of IOD forcing in explaining the Pacific variability associated with ENSO via ITF. 相似文献
94.
利用1998-2014年20场北疆典型寒潮天气过程的高空、地面和数值预报产品资料,对北疆寒潮天气进行了环流分型和区域分型,总结了环流型与冷空气路径、区域类型的对应关系,重点统计了不同季节北疆寒潮爆发前一天内500hPa脊前北风急流、锋区强度、中低空冷空气强度、地面冷高压等特征量的平均值和最大、最小值,并检验欧洲ECMWF数值预报产品在北疆寒潮天气预报中的预报能力,为北疆寒潮精细化预报提供了技术参考。 相似文献
95.
J. A. Combi J. F. Albacete Colombo L. Pellizza J. López-Santiago G. E. Romero J. Martí A. J. Muñoz-Arjonilla E. Sánchez-Ayaso P. L. Luque-Escamilla J. R. Sánchez-Sutil 《Astrophysics and Space Science》2011,331(1):53-61
We present a catalog of cross-correlated radio, infrared and X-ray sources using a very restrictive selection criteria with
an IDL-based code developed by us. The significance of the observed coincidences was evaluated through Monte Carlo simulations
of synthetic sources following a well-tested protocol. We found 3320 coincident radio/X-ray sources with a high statistical
significance characterized by the sum of error-weighted coordinate differences. For 997 of them, 2MASS counterparts were found.
The percentage of chance coincidences is less than 1%. X-ray hardness ratios of well-known populations of objects were used
to provide a crude representation of their X-ray spectrum and to make a preliminary diagnosis of the possible nature of unidentified
X-ray sources. The results support the fact that the X-ray sky is largely dominated by Active Galactic Nuclei at high galactic
latitudes (|b|≥10°). At low galactic latitudes (|b|≤10°) most of unidentified X-ray sources (∼94%) lie at |b|≤2°. This result suggests that most of the unidentified sources found toward the Milky Way plane are galactic objects. Well-known
and unidentified sources were classified in different tables with their corresponding radio/infrared and X-ray properties.
These tables are intended as a useful tool for researchers interested in particular identifications. 相似文献
96.
97.
浙江八面山萤石矿床流体包裹体地球化学研究 总被引:2,自引:1,他引:1
八面山萤石矿床流体包裹体可分为三大类型:Ⅰ气液包裹体,Ⅱ气体包裹体,Ⅲ含子矿物的多相包裹体;矿床成矿温度变化不大,主要集中在120~240°C之间。细粒条带状萤石矿石包裹体温度变化在115~250℃之间;巨晶块状萤石矿石和石英脉型萤石矿石包裹体温度集中在135~170℃之间。萤石矿床流体包裹体以低盐度成矿流体为主。成矿过程中起作用的成矿流体为KCl-H2O体系和CO2-CaF2-H2O体系,成矿溶液的离子类型属K+-Ca2+-HCO--F-型,KCl-H2O体系反映岩浆期后热液作用的结果,而CO2-CaF2-H2O体系可能反映了寒武纪矿源层成矿体系。通过包裹体研究,认为八面山萤石矿床是受地层-岩体-层间断裂共同控制"三位一体"的热液成因矿床。 相似文献
98.
岩性油藏地震描述技术在准噶尔盆地春光油田的应用 总被引:1,自引:1,他引:0
准噶尔盆地春光油田新近系沙湾组岩性油藏埋藏浅、厚度薄、成岩作用差,勘探效果不理想。利用层拉平切片技术确定有利储集相带、分频技术雕刻砂体、"类亮点"特征检测流体、进一步采用拟声波+电阻率反演两步法鉴别流体,这一技术方法系列在春光油田的实际应用效果良好。用拟声波+电阻率反演两步法可以检测出无亮点特征的含油砂体或含水砂体。对于不具备"类亮点"特征的滩坝砂油藏的勘探,可由原来的应用"类亮点"特征直接找油转为寻找有效圈闭,并在此基础上应用合适的流体检测技术,这同样可以发现有利的滩坝砂油藏。 相似文献
99.
Contamination levels assessment of potential toxic metals in road dust deposited in different types of urban environment 总被引:1,自引:1,他引:0
A total of 42 samples of road dust were collected along ring road, city centre, city side, and freeway in Urumqi, China. Total
concentrations of Cd, Cr, Cu, Ni, Pb, Mn, Be, Co, Zn, and U were determined by using the inductively coupled plasma-mass spectrometry
in order to assess and to compare road dust contamination levels of metals among the four roads. The results show that, among
the four categories of roads, mean concentrations of Co and U vary little. City centre locations show strong enrichments of
Cd, Cu, Pb, and Be. Along the ring road, the highest mean concentrations were found for Cr, Ni, Mn, and Co. However, the highest
concentrations of Zn and U were found along the freeway. The cluster analysis shows that three main groups can be distinguished.
Every group may be associated with different main sources and concentrations of the metals. The results of contamination assessment
reveal that, among all of the potential toxic metals, Cd, Cu, and Zn pollution were obviously heavier with moderate or high
contamination indices for most road dust samples, while Cr, Ni, and Pb contamination were lower along the four categories
of roads. Compared with the city side, Cd, Cu, Pb, Ni, and Zn contamination were heavier along the ring road, the city centre,
and the freeway with high traffic density. Low Pb contamination or no contamination in all the road dust samples may be related
to the increasing usage of lead-free petrol. 相似文献
100.
Shuo Chen Renhai Pu Huiqiong Li Hongjun Qu Tianyu Ji Siyu Su Yunwen Guan Hui Zhang 《海洋学报(英文版)》2022,41(9):86-106
The Dongfang1-1 gas field (DF1-1) in the Yinggehai Basin is currently the largest offshore self-developed gas field in China and is rich in oil and gas resources. The second member of the Pliocene Yinggehai Formation (YGHF) is the main gas-producing formation and is composed of various sedimentary types; however, a clear understanding of the sedimentary types and development patterns is lacking. Here, typical lithofacies, logging facies and seismic facies types and characteristics of the YGHF are identified based on high-precision 3D seismic data combined with drilling, logging, analysis and testing data. Based on 3D seismic interpretation and attribute analysis, the origin of high-amplitude reflections is clarified, and the main types and evolution characteristics of sedimentary facies are identified. Taking gas formation upper II (IIU) as an example, the plane distribution of the delta front and bottom current channel is determined; finally, a comprehensive sedimentary model of the YGHF second member is established. This second member is a shallowly buried “bright spot” gas reservoir with weak compaction. The velocity of sandstone is slightly lower than that of mudstone, and the reflection has medium amplitude when there is no gas. The velocity of sandstone decreases considerably after gas accumulation, resulting in an increase in the wave impedance difference and high-amplitude (bright spot) reflection between sandstone and mudstone; the range of high amplitudes is consistent with that of gas-bearing traps. The distribution of gas reservoirs is obviously controlled by dome-shaped diapir structural traps, and diapir faults are channels through which natural gas from underlying Miocene source rocks can enter traps. The study area is a delta front deposit developed on a shallow sea shelf. The lithologies of the reservoir are mainly composed of very fine sand and coarse silt, and a variety of sedimentary structural types reflect a shallow sea delta environment; upward thickening funnel type, strong toothed bell type and toothed funnel type logging facies are developed. In total, 4 stages of delta front sand bodies (corresponding to progradational reflection seismic facies) derived from the Red River and Blue River in Vietnam have developed in the second member of the YGHF; these sand bodies are dated to 1.5 Ma and correspond to four gas formations. During sedimentation, many bottom current channels (corresponding to channel fill seismic facies) formed, which interacted with the superposed progradational reflections. When the provenance supply was strong in the northwest, the area was dominated by a large set of delta front deposits. In the period of relative sea level rise, surface bottom currents parallel to the coastline were dominant, and undercutting erosion was obvious, forming multistage superimposed erosion troughs. Three large bottom current channels that developed in the late sedimentary period of gas formation IIU are the most typical. 相似文献