数字城市地理空间框架建设项目三维城市模型建设技术研究   总被引：1，自引：0，他引：1  

郭海青 《测绘通报》2013,(4):86-87,96

通过研究数字城市构建的目的、意义,确定三维城市建设先进性、规范性、开发性的建设原则,从三维城市模型建设的关键问题入手,针对城市大范围模型构建的特点,选择自动建模和精细建模两种方式,并讨论两种建模方法的优缺点,以及纹理大小、模型构建精细程度、不同地物的建模要求等问题。  相似文献   

4种再分析月降水数据在内蒙古地区的适用性分析          下载免费PDF全文

曲学斌  王涵  乌尼尔  孙小龙  刘朋涛  宋海清 《中低纬山地气象》2023,47(1):75-81

利用1981—2020年气象台站的实测降水数据,对CRA40、ERA5、JRA55和MERRA2这4种再分析月降水数据在内蒙古地区的降水分布特征,与实测降水的相关性和误差进行分析。结果表明：（1）内蒙古地区4种再分析降水数据的空间分布与台站降水基本一致,误差分析表明CRA40与MERRA2的数据质量较高,ERA5次之,而JRA55数据质量相对较差。（2）CRA40和MERRA2在1983—1986年存在明显的降水低估,ERA5在2005年之后的内蒙古中东部出现明显的降水低估,JRA55在115°E以东存在明显降水高估,在115°E以西则以降水低估为主。（3）4种再分析月降水数据的年内最大均方根误差和绝对误差均集中在6—8月,与台站降水相关系数的年内最小值均出现在7月,内蒙古夏季汛期是再分析降水误差产生的主要时段。  相似文献   

渤海湾盆地东营凹陷碎屑流主控型深水体系沉积过程及模式          下载免费PDF全文

刘建平  鲜本忠  张莉  苏明  李宇志  闫海清  王震  陈鹏  吴千然  李晋  田荣恒  杨鑫  周欢焕  罗勋  陈龙 《中国地质》2022,49(6):1951-1969

【研究目的】碎屑流是深水环境沉积物搬运和分散的重要机制,其相关的砂岩储层是含油气盆地重要的勘探目标,然而,与经典浊流及浊积系统相比,对碎屑流主控型深水体系的发育规律目前仍知之甚少。【研究方法】本文基于岩心、测井及全三维地震资料,通过系统的岩心观察描述、测井及地震资料解释,对渤海湾盆地东营凹陷始新统沙三中亚段深水体系沉积过程及模式开展研究。【研究结果】结果表明,沙三中深水体系发育九种异地搬运岩相,可概括为四大成因类型,反映了块体及流体两种搬运过程。岩相定量统计表明,该深水体系主要由碎屑流沉积构成,浊流沉积很少,碎屑流中又以砂质碎屑流为主。重力流在搬运过程中经历了滑动、滑塌、砂质碎屑流、泥质碎屑流及浊流等5个阶段演变,发育5类主要的深水沉积单元,包括滑动体、滑塌体、碎屑流水道、碎屑流朵体及浊积薄层砂。从发育规模及储层物性上,砂质碎屑流水道、朵体及砂质滑动体构成了本区最重要的深水储层类型。【结论】认为沙三中时期充足的物源供给、三角洲前缘高沉积速率、断陷期频繁的断层活动以及较短的搬运距离是碎屑流主控型深水体系形成及演化的主控因素,最终基于沉积过程、沉积样式及盆地地貌特征综合建立了碎屑流主控型深水体系沉积模式。本研究将进一步丰富深水沉积理论,为陆相深水储层预测提供借鉴。  相似文献   

河南西峡石板沟金矿床蚀变岩矿物共生分析     

耿海清 《黄金地质》1999,5(2):27-31

石板沟金矿床的主要矿石类型为蚀变岩型和石英脉型,矿化与蚀变关系密切。通过矿物共生分析和石英中氢氧同位素测试等手段,认为成矿热液主要来源于变质水;并在此基础上,对矿床的成因控制及其演化过程进行了详细分析,确定该矿为中高温变质热液蚀变岩型金矿床。  相似文献   

论中国半精养水库渔业及其饲料问题     

贺锡勤  盛海清  许国焕 《湖泊科学》1995,7(4):365-373

中国水库放养鱼的种类、食性以及可利用的天然饵料生物决定了半精养渔业是水库渔业的主要模式。水库半精养有中、小型水库、水库库汊、网拦、网围、网箱养鱼等多种形式。其产量与肥料、饲料的投入有直接关系。最大限度地利用天然饵料,并辅以补充性人工饲料,可实现高产高效。本文以水库鱼类的营养和饲料利用为基础,论述半精养水库渔业的理论和实用技术,并提出尚须研究的问题,以推进半精养水库渔业的发展。  相似文献   

湖泊磷的核磁共振(NMR)分析——1环境标准样品的³¹P-NMR表征   总被引：1，自引：0，他引：1  

王晓钧  丁士明  蒋海青  白秀玲  范成新 《湖泊科学》2008,20(1):45-50

通过对环境标准样进行31P-NMR测试,研究了磷的化学结构与化学位移的关系.结果表明:无机正磷酸盐(PO43-)化学位移在6.412×10-6,焦磷酸盐的化学位移在-4.353×10-6;多聚磷的化学位移分布特点是:主链末端磷化学位移在-3.53×10-6至-4.40×10-6之间,中间磷在-18.159×10-6至-20.246×10-6之间,有机磷中单酯和二醑的化学位移分别在4.3540×10-6至6.3652×10-6和-0.107×10-6至2.195×10-6之间,部分二脂不稳定,会降解为单脂;膦酸盐的化学位移在18.670×10-6至21.460×10-6之间,磷酸肌酸位于-0.380×10-6,有机多聚磷中α-P的化学位移在-8.833×10-6至-9.449×10-6之间,由于偶合作用产生P峰的裂分,P峰的偶合符合核磁中n 1的规则.结构环境影响31P的化学位移值的偏移.  相似文献   

Beach-fill equilibration and dune growth at two large-scale nourishment sites     

Haiqing Liu Kaczkowski  Timothy W. Kana  Steven B. Traynum  Ruben Visser 《Ocean Dynamics》2018,68(9):1191-1206

Natural dune growth after nourishment is often observed, and such growth plays an important role in beach management for coastal communities. Nourishment sand equilibration after construction is another important topic for project planning and design. Large-scale nourishment projects at Nags Head (NC, USA) (completed in 2011) and Bridgehampton–Sagaponack (NY, USA) (completed in 2014) are under comparatively high-wave energy conditions and offer new insight regarding these topics. After nourishment, a natural beach and inshore morphology were produced with high rates of dune growth by eolian transport. At Nags Head, volumetric dune growth averaged 8 m³/m/yr over the first 5 years following project completion, while Bridgehampton–Sagaponack averaged 9 m³/m/yr over the first 3 post-project years. Results are compared with the Bagnold (1941) analytical model predictions of dune growth and are shown to correlate and decay closely with dry-sand beach width as the nourished profile equilibrates. The extra volume and elevation in the dunes have provided a higher level of storm protection and have helped the sites avoid any major damage to oceanfront properties during hurricanes or numerous severe winter storms.  相似文献   

Shear strength of frozen clay under freezing-thawing cycles using triaxial tests     

Miao Wang  Shangjiu Meng  Yiqiang Sun  Haiqing Fu 《地震工程与工程振动(英文版)》2018,17(4):761-769

Using a new low-temperature dynamic triaxial apparatus, the influence law of freezing-thawing cycles on clay shear strength is studied. In this research, the concept of correction coefficients of freezing-thawing cycles on clay static strength, cohesion and internal friction angles is proposed, and the change patterns, correction curves and regressive formulae of clay static strength, cohesion and internal friction angles under freezing-thawing cycles are given. The test results indicate that with increasing numbers of freezing-thawing cycles, the clay static strength and cohesion decrease exponentially but the internal friction angle increases exponentially. The performance of static strength, cohesion and internal friction angles are different with increasing numbers of freezing-thawing cycles, i.e., the static strength decreases constantly until about 30% of the initial static strength prior to the freezing-thawing cycling and then stays basically stable. After 5–7 freezing-thawing cycles, the cohesion decreases gradually to about 70% of the initial cohesion. The internal friction angle increases about 20% after the first freezing-thawing cycle, then increases gradually close to a stable value which is an increase of about 40% of the internal friction angle. The freezing-thawing process can increase the variation of the density of the soil samples; therefore, strict density discreteness standards of frozen soil sample preparation should be established to ensure the reliability of the test results.  相似文献   

基于同位素技术的珲春盆地浅层地下水可更新能力研究     

石旭飞  赵海卿  郭晓东 《水文》2017,37(4):40-44

利用~3H的示踪作用对珲春盆地浅层地下水更新速率进行计算,为该地区制定地下水开发利用模式和水资源环境承载力研究提供科学依据。结果表明:总体上,珲春盆地大部分地区浅层地下水更新速率大于8%/a,可更新能力较强。珲春盆地东北部平安村、新华村、马新村和东部的红星村、电线村、东兴村等山前地区以及八一村、八二村等地浅层地下水更新速率大于10%/a,可更新能力较强;七户洞村、八棵树村、永丰村、立新村、新农村、柳亭村等地浅层地下水更新速率为8%/a~10%/a,可更新能力减弱;八家子村、西崴子村、孟岭村等珲春河下游地区浅层地下水更新速率小于8%/a,可更新能力最弱。更新速率为大于10%/a、8%/a~10%/a、小于8%/a的地下水分布面积占珲春盆地总面积的比例分别为67%、26%、7%。  相似文献   

Impact of the snow cover scheme on snow distribution and energy budget modeling over the Tibetan Plateau   总被引：1，自引：0，他引：1  

Zhipeng?Xie  Zeyong?HuEmail author  Zhenghui?Xie  Binghao?Jia  Genhou?Sun  Yizhen?Du  Haiqing?Song 《Theoretical and Applied Climatology》2018,131(3-4):951-965

This paper presents the impact of two snow cover schemes (NY07 and SL12) in the Community Land Model version 4.5 (CLM4.5) on the snow distribution and surface energy budget over the Tibetan Plateau. The simulated snow cover fraction (SCF), snow depth, and snow cover days were evaluated against in situ snow depth observations and a satellite-based snow cover product and snow depth dataset. The results show that the SL12 scheme, which considers snow accumulation and snowmelt processes separately, has a higher overall accuracy (81.8%) than the NY07 (75.8%). The newer scheme performs better in the prediction of overall accuracy compared with the NY07; however, SL12 yields a 15.1% underestimation rate while NY07 overestimated the SCF with a 15.2% overestimation rate. Both two schemes capture the distribution of the maximum snow depth well but show large positive biases in the average value through all periods (3.37, 3.15, and 1.48 cm for NY07; 3.91, 3.52, and 1.17 cm for SL12) and overestimate snow cover days compared with the satellite-based product and in situ observations. Higher altitudes show larger root-mean-square errors (RMSEs) in the simulations of snow depth and snow cover days during the snow-free period. Moreover, the surface energy flux estimations from the SL12 scheme are generally superior to the simulation from NY07 when evaluated against ground-based observations, in particular for net radiation and sensible heat flux. This study has great implications for further improvement of the subgrid-scale snow variations over the Tibetan Plateau.  相似文献