城市效应对登陆热带气旋妮妲降水影响的模拟

运用中尺度数值模式WRF耦合城市冠层模式（urban canopy model,UCM）,对2016年登陆深圳的热带气旋妮妲（1604）（以下简称妮妲）进行数值模拟。高分辨率数值模拟较好地再现了妮妲登陆前后的强度、路径和累积降水。利用城市化过程当中城市冠层对热带气旋降水的敏感性试验结果表明:城市冠层会减弱对流运动和水汽的输送,导致热带气旋登陆后珠江口城市群区域累积降水量略减少。应用最新的土地利用资料进行的城市下垫面敏感性试验结果表明:由于城市下垫面粗糙度增加,造成登陆地面风的减速,强度减弱,潜热通量与2 m高度比湿相应减小;城市下垫面粗糙度增加会加强该区域垂直对流运动以及不稳定能量增加,有利于降水增强,尤其在城市化下垫面处,热带气旋登陆后6 h累积降水增加量最大可超过20 mm。总体而言,对登陆热带气旋降水而言,耦合城市冠层使城市区域热带气旋降水减少,但在数值模拟中城市冠层影响作用不显著。城市化下垫面对登陆热带气旋暴雨的增幅作用明显,在登陆热带气旋降水预报中应重视。     

CMIP5全球气候模式对1981—2005年东北地表温度的模拟分析

利用中国东北1981—2005年173个气象台站观测的月平均地表(0 cm)温度资料和参加IPCC第五次评估报告的43个全球气候模式模拟结果,对比分析了CMIP5耦合气候模式对中国东北地区地表温度的模拟性能。结果表明：大部分气候模式模拟结果都能较好的再现研究区域的地表温度时空变化,与月观测的时间相关系数均高于095,对年际变化模拟能力稍差,大部分模式模拟结果在整个研究时段均表现出冷偏差。空间分布显示,CMIP5模式能够模拟出中国东北地区地表温度南高北低的空间分布特征,但不同模式模拟结果之间差异较大,模拟能力较优模式能够较好的模拟出研究区域的冷暖中心,较优模式组和较差模式组在夏季的差距达到最大,较差模式组不能再现地表温度的分布特征。通过模式优选发现FGOALS_s2模式表现最优。总的来说,CMIP5耦合气候模式对中国东北区域地表温度的时空变化特征的模拟性能较好,对气候态年变化的模拟性能好于对年际变化的模拟。     

鄂尔多斯盆地子洲气田上古生界山西组、下石盒子组储集层特征对比研究

鄂尔多斯盆地子洲气田山西组山23段和下石盒子组盒8段是该区天然气的主力储集层, 但其产能却存在很大差异.应用薄片鉴定、扫描电镜、高压压汞、恒速压汞及岩心分析资料, 分别对该地区上古生界山西组山23段和下石盒子组盒8段储集层进行了研究.子洲气田山23储层以石英砂岩为主, 孔隙类型多样, 粒间孔、溶孔、晶间孔发育, 喉道类别以微—细喉为主, 属相对低孔高渗型储层; 盒8储层则以岩屑砂岩为主, 孔隙类型主要为岩屑溶孔和晶间孔, 喉道类别以细—微喉为主, 属于相对低孔低渗型储层.山23段和盒8段储集层岩石类型、孔隙结构差别巨大, 造成了其储集性能的差异性.不同的沉积环境和成岩作用是造成其差异性的主要原因.     

饱和软土压缩曲线的“反常”现象

饱和软土压缩试验时,经常出现压缩曲线“反常”、压缩系数“倒大”的现象。它是土的原始结构发生破坏前后的不同压缩性的客观反映。饱和软土的结构力很微弱,唯质量好的原状土才能见到这种“反常”。应从成孔、取样、测试及资料整理等多个环节保证其工程意义。     

The Lower Changjiang (Yangzi/Yangtze River) metallogenic belt, east central China: intrusion- and wall rock-hosted Cu–Fe–Au, Mo, Zn, Pb, Ag deposits

The lower valley of Changjiang, from Wuhan of the Hubei Province in the west to Zhenjiang of the Jiangsu Province in the east, contains more than 200 polymetallic (Cu–Fe–Au, Mo, Zn, Pb, Ag) deposits and is one of the most important metallogenic belts in China. This metallogenic belt, situated at the northern margin of the Yangzi craton and bordered by the Dabieshan ultrahigh pressure metamorphic belt to the north, consists mainly of Cambrian–Triassic marine clastic sedimentary rocks and carbonate and evaporite rocks, which overlay a Precambrian basement and are intruded by Yanshanian (205 to 64 Ma) granitoid intrusions and subvolcanic complexes. Repeated tectonism from Late Proterozoic to Triassic resulted in extensively developed networks of faults and folds involving the Cambrian–Triassic sedimentary strata and the Precambrian basement. The Yanshanian granitoid intrusions and subvolcanic complexes in the Lower Changjiang metallogenic belt are characterized by whole-rock δ¹⁸O of +8‰ to +10‰, initial ⁸⁷Sr/⁸⁶Sr of 0.704 to 0.708, and εNd^t from −10 to −17 and have been interpreted to have originated from mixing between juvenile mantle and old crustal materials. Also, the Yanshanian granitoids exhibit eastward younging and increase in alkalinity (i.e., from older calc–alkaline in the west to younger subalkaline–alkaline in the east), which are related to oblique collision between the Yangzi and Sino-Korean cratons and tectonic evolution from early compressional to late extensional or rifting regimes. Most polymetallic deposits in the Lower Changjiang metallogenic belt are clustered in seven districts where the Yanshanian magmatism is particularly extensive: from west to east, Edong, Jiurui, Anqing–Guichi, Luzhong, Tongling, Ningwu and Ningzhen. Mineralization is characterized by the occurrence of three distinct types of orebodies in individual deposits: orebodies in Yanshanian granitoid intrusions, skarn orebodies at the contact zones between the Yanshanian intrusions and Late Paleozoic–Early Mesozoic sedimentary rocks, and stratabound massive sulfide orebodies in the Late Paleozoic–Early Mesozoic sedimentary strata. The most important host sedimentary strata are the Middle Carboniferous Huanglong Formation, Lower Permian and Lower–Middle Triassic carbonate and evaporite rocks. The intrusion-hosted and skarn orebodies exhibit well-developed zonation in alteration assemblages, metal contents, and isotopic compositions within individual deposits, and apparently formed from hydrothermal activities related to the Yanshanian magmatism. The stratabound massive sulfide orebodies in the Late Paleozoic–Early Mesozoic sedimentary strata have long been suggested to have formed from sedimentary or volcano-sedimentary exhalative processes in shallow marine environments. However, extensive research over the last 40 years failed to produce unequivocal evidence for syngenetic mineralization. On the basis of geological relationships and isotope geochemical characteristics, we propose a carbonate-hosted replacement deposit model for the genesis of these stratabound massive sulfide orebodies and associated skarn orebodies. This model suggests that epigenetic mineralization resulted from interactions between magmatic fluids evolved from the Yanshanian intrusions with carbonate and evaporite wall rocks. Mineralization was an integral but distal part of the larger hydrothermal systems that formed the proximal skarn orebodies at the contact zones and the intrusion-hosted orebodies. The stratabound massive sulfide deposits of the Lower Changjiang metallogenic belt share many features with the well-studied, high-temperature, carbonate-hosted replacement deposits of northern Mexico and western United States, particularly with respect to association with small, shallow granitoid complexes, structural and stratigraphic controls on mineralization, alteration assemblages, geometry of orebodies, metal association, metal zonation and isotopic systematics.     

大气季节内振荡：其全球同步性及其与ENSO的关系

利用美国国家环境预报中心和大气研究中心的大气再分析资料，分析研究了大气季节内振荡的年际变化及其与ＥＮＳＯ的关系。揭示了全球不同纬度带之间存在着的大气季节内振荡年际变化的同步性，以及大气季节内振荡与海温和大气向外长波辐射之关系的复杂性。我们还发现大气季节内振荡与Ｎｉｎｏ３指数的关系存在年代际尺度的变化，即，这种关系有时强时弱的现象。     

Koreatown and Korean Small Firms in Los Angeles: Locating in the Ethnic Neighborhoods*

The locations of Korean firms in Los Angeles reflect spatial segmentation in markets and the provision of labor, in that the ethnic neighborhoods facilitate positive business environments for ethnic small firms. While Korean small businesses serve both community needs and broader local markets, firm locations are closely associated with the residential patterns of some ethnic populations. To address the specificity of firm locations, this paper examines Koreatown using historical sources and recent property development, identifies changes in the locational patterns of Korean firms between 1975 and 1986, and analyzes relationships between business density and density of ethnic populations for zip code areas. The findings of this study indicate that both the development of Koreatown and the presence of ethnic neighborhoods are important influences on the location of Korean businesses.     

UbD理论指导下的高中地理逆向教学设计——以"中国的能源安全"为例

高中地理课程改革要求重视学科大概念。UbD理论提出的逆向教学设计是在教学中落实学科大概念的重要途径。UbD理论指导下的逆向教学设计以学科大概念为核心、以学习结果为起点、评价优先,能够在教学中凸显学科大概念的价值和作用,符合新课程改革的理念。本文以人教版高中地理选择性必修3中的“中国的能源安全”为例进行逆向教学设计,提出在地理课堂中应用UbD理论进行逆向教学设计的策略。     

利用物理方法确定外方位元素的卫星立体摄影测量的精度分析

本文在分析用物理方法确定外方位元素的情况下卫星立体摄影测量的精度影响因素,推导了卫星立体摄影测量的理论精度计算公式,并以SPOT5 HRS立体像对为例,计算了SPOT5 HRS立体测量的理论精度,进行了利用少量地面控制点的立体测量试验。结果证明卫星立体摄影测量的理论精度估算公式是正确的,同时SPOT5 HRS立体测量精度能够满足1∶50000测图的要求。     

基于RFPA3D和微震监测的白鹤滩水电站左岸边坡稳定性分析

白鹤滩水电站左岸边坡受缓倾角软弱面及NW向断层影响,施工、运行期的边坡稳定性问题尤为重要。为研究左岸边坡在开挖卸荷过程中应力场、位移场分布规律,揭示岩体内部破坏失稳机制,利用RFPA3D（realistic failure process analysis）软件以拱轴线剖面为例建立准三维数值模型,再现坝基边坡岩体裂隙萌生、发育、扩展直至贯通的渐进损伤破坏过程。结合左岸边坡开挖卸荷及应力调整过程中的微震活动演化特征,圈定工程边坡潜在危险区域,探讨可能的失稳破坏模式。分析表明：基于离心加载法计算得到工程边坡开挖后安全系数为1.33;边坡表层区域受缓倾角错动带控制,变形破坏最为明显,以小范围楔形体滑移为主。该研究结果可为白鹤滩水电站坝基边坡后期施工提供依据,对于类似岩质边坡工程施工具有一定的指导作用。