准噶尔盆地中侏罗统西山窑组与头屯河组间不整合面特征及其油气勘探意义   总被引：3，自引：1，他引：2  

何登发  周路  唐勇  吴晓智  杜社宽 《古地理学报》2007,9(4):387-396

准噶尔盆地侏罗系顶、底及其内部不整合广泛发育,其中中侏罗统下部西山窑组和上部头屯河组之间的角度不整合尤为清楚。它表现为区域性不整合,沉积间断时限达4～10 Ma,剥蚀厚度达100～340 m。该不整合“面”的结构由不整合面之上的砂岩、不整合面之下的风化粘土层和半风化岩石组成,以砂岩-泥岩-砂岩的组合为主,平均厚度达70～90 m。依靠风化粘土层,不整合面之上头屯河组的砂岩形成了地层超覆圈闭,不整合面之下西山窑组的砂岩形成了地层削截不整合遮挡圈闭。油气勘探实践表明：该不整合面上、下是油气聚集的重要场所;该不整合面的后期掀斜演变对油气聚集和调整再分配产生了重要影响。  相似文献   

Noise reduction for broad-band, three-component seismograms using data-adaptive polarization filters   总被引：2，自引：0，他引：2  

Zhijun Du  G. R. Foulger  & Weijian Mao 《Geophysical Journal International》2000,141(3):820-828

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生态地理区域系统的热带北界中段界线的新认识   总被引：16，自引：3，他引：13  

吴绍洪  郑度 《地理学报》2000,55(6):689-697

从我国热带北界中段界线的划分,探讨生态地理区域的认识和界线的划分,着重生态地理区域之间界线的逐渐过渡特征。分析前人的研究成果及其对热带北界中段划分的差异,指出他们在概念、资料和方法上的差异。在热带与亚热带的过渡区域中提出热带、年热带、真热带和热带波动带的概念,从新的角度认识热带区域。在确定和建立热带北界划分指标体系的基础上,划分了热带北界中段的界线。探讨了本次热带北界中段的界线划分与前人研究的差异  相似文献   

关于我国华北沙尘天气的成因与治理对策   总被引：148，自引：6，他引：142  

叶笃正  丑纪范 《地理学报》2000,55(5):513-521

２０００年春季,我国华北沙尘天气次数陡增,影响广泛,损失明显增加。利用长期气象观测数据,结合遥感和ＧＩＳ技术,对今年华北沙尘天气的成因进行分析,提出造成沙尘天气的原因在于：①北方地区大风日数的增减是气候周期性变化的反映,今年强沙尘天气陡增是因为处于反厄尔尼诺事件的高峰期所致;②我国北方地表覆被状况局部改善、整体恶化也是今年强沙尘天气产生的另一重要原因。影响华北地区的沙尘天气主要必源于内蒙古中西部和  相似文献   

Distribution characteristics of zooplankton in the south part of Taiwan Strait in summer     

Zhu Changshou  Huang Jiaqi  Lin Junzhou  Du Qinghong  Chen Xu  Li Shaojing 《海洋学报(英文版)》2000,19(1):127-135

INTRODUCTIONInfluencedbywarmcurrent,upwellingandalongshore(coastal)waters,zooplanktoniscomparativelyabundantinthesouthpartofTaiwanStrait.Inthepast,macroplanktonnetwasadoptedintheecologicalstudyofzooplanktoninthisarea,thuscausingconsiderablelossofeitherspeciesorindividualnumbersofmeso-andmicrozooplanktoninthesurvey.Inthisstudy,mesozooplanktonnetwasusedinthesamplecollection.Itshowsthatmicrozooplanktonandimmatureindividualsofmacro-andmesozooplanktonwereabundant,andthediversityofzooplanktoni…  相似文献   

Dispersion relation of internal waves in the western equatorial Pacific Ocean   总被引：4，自引：1，他引：3  

Fang Xinhu  Jiang Mingshun  Du Tao 《海洋学报(英文版)》2000,19(4):37-45

Based mainly on TOGA COARE data, that is, the CI''D data from R/V Xiangyanghong No.5 (Pu et al.,1993),the temperature and current data from the Woods Hole mooring and other deep current data, the layered numerical profiles of buoyancy frequency and mean current components are figured out.A numerical method calculating internal wave dispersion relation without background shear current, used by Fliegel and Hunkins (1975),is improved to be fit for the internal wave equation with mean currents and their second derivatives.The dispersion relations and wave functions of the long crested internal wave progressing in any direction can be calculated inveniently by using the improved method.A comparison between the calculated dispersion relation in the paper and the dispersion relation in GM spectral model of ocean internal waves (Garret and Munk, 1972) is performed.It shows that the mean currents are important to the dispersion relation of internal waves in the western equatorial Pacific Ocean and that the currents make the wave progressing co-directional with (against) the currents stretched (shrink).The influence of the mean currents on dispersion relation is much stronger than that of their second derivatives, but that on wave function is less than that of their second derivatives.The influences on wave functions result in the change of vertical wavenumber, that is, making the wave function stretch or shrink.There exists obvious turning depth but no significant critical layer absorption is found.  相似文献   

祁连山中部树木年轮宽度与气候因子的响应关系及气候重建   总被引：33，自引：13，他引：20  

王亚军  陈发虎  勾晓华  杜淑英 《中国沙漠》2001,21(2):135-140

研究了祁连山中部不同海拔高度青海云杉的树轮宽度对气候因子的响应,重建了祁连山中部 230 a以来春季3~5月的降水和 170 a以来夏季6~8月的气温序列。结果分析发现,不同高度的云杉树轮生长对春季降水极为敏感,呈现显著正相关;对夏季气温的响应程度,各海拔高度却不相同,夏季气温对上、下限云杉生长有显著影响,但对于森林中部云杉作用并不明显,总体表现为负相关,夏季高温对树木生长不利。气候重建结果发现,祁连山中部的春季230 a以来经历了大幅度长阶段的干湿变化,存在明显的 69 a和 21a周期;170 a以来夏季气温变化频繁,存在明显的2~4a周期。目前,祁连山中部正处于相对干旱和温暖时期,呈现出向暖干方向发展的趋势。  相似文献   

旅游中心地研究及其规划应用   总被引：35，自引：4，他引：31  

柴彦威  林涛  刘志林  曹艺民 《地理科学》2003,23(5):547-553

在对已有旅游中心地相关研究回顾的基础上,探讨了旅游中心地的概念与界定方法,分析了旅游中心地理论在旅游空间规划中的指导意义,并以吉林省旅游发展总体规划为例,介绍如何将旅游中心地的理论运用到实际的旅游规划当中。  相似文献   

Assessing spatial and temporal variability in water consumption and the maintainability oasis maximum area in an oasis region of Northwestern China     

XueXiang Chang  WenZhi Zhao  XueLi Chang  Bing Liu  Jun Du 《寒旱区科学》2020,12(4):217-233

Water consumption is a key role in improving the efficiency and sustainability of water management in arid environments.In this study, we explored an approach based on meta-analysis, MODIS NDVI products, land-use spatial distribution, and soil water physical parameters to gain insight into long-term and large scale distribution of land use and water consumption, maintain maximum Zhangye Oasis area according to Heihe River runoff, and suitable water resource management in Zhangye Oasis. This approach was initiated in order to improve the efficiency of irrigation and water resource management in arid regions. Results showed that Heihe River runoff can maintain a maximum Zhangye Oasis area of 22.49×10~4 hm~2.During the 2000-2016 growing seasons, actual oasis water consumption ranged from 11.35×10~8 m~3 to 13.73×10~8 m~3, with a mean of(12.89 ± 0.60)×10~8 m~3; if maintaining agricultural production and oasis stability was chosen, oasis water consumption ranged from 10.24×10~8 m~3 to 12.37×10~8 m~3, with a mean of(11.62 ± 0.53)×10~8 m~3. From the perspective of water resources management and ecosystem stability, it is necessary to reduce the area of Zhangye Oasis or choose the minimum water consumption method to manage the oasis, to ease the pressure of water shortage and maintain stable and sustainable development of the Zhangye Oasis. These results can provide future practical guidance for water resource management of coordinated development of the economy and the environment in an arid area.  相似文献   

Soil moisture temporal stability and spatio-temporal variability about a typical subalpine ecosystem in northwestern China     

Xi Zhu  Zhibin He  Jun Du  Longfei Chen  Pengfei Lin  Quanyan Tian 《水文研究》2020,34(11):2401-2417

Knowledge of the spatial–temporal variability of soil water content is critical for water management and restoration of vegetation in semi-arid areas. Using the temporal stability method, we investigated soil water relations and spatial–temporal variability of volumetric soil water content (VSWC) in the grassland–shrubland–forest transect at a typical semi-arid subalpine ecosystem in the Qilian Mountains, northwestern China. The VSWC was measured on 48 occasions to a depth of 70 cm at 50 locations along a 240-m transect during the 2016–2017 growing seasons. Results revealed that temporal variability in VSWC in the same soil layer in the three vegetation types and averaged across vegetation types tended to exhibit similar patterns of a decrease with increasing soil depth. Temporal stability in each vegetation type was stronger with an increase in soil depth. However, the results of temporal stability determined with standard deviation of relative difference (SDRD) disagreed with those based on the Spearman's rank correlation coefficient; the forest site had the highest Spearman rank correlation coefficient while the shrubland—the smallest SDRD in the 0–20 cm soil layer. Correlation analyses of VSWCs between two vegetation types indicated that soil water was related among all three vegetation types at the 0–20, and 0–70 cm soil layer, but in the 20–40 and 40–70 cm soil layers, significant correlation (p < .01) occurred only between adjacent vegetation types. In the upper soil layer (0–20 cm), soil water relations were mainly affected by surface runoff. In the lower soil layer (20–40 and 40–70 cm), soil water relations among the three vegetation types were highly complex, and probably resulting from a combination of root distribution and activity, interflow, and the impact of deep soil freeze–thaw dynamics. These results suggest that the factors affecting soil water are complex, and further research should address the relative importance of and interactions among different determining factors.  相似文献