Landslide susceptibility assessment using evidential belief function,certainty factor and frequency ratio model at Baxie River basin,NW China     

Zhuo Chen  Yutian Ke  Zhikun Yang  Hongliang Zhao 《国际地球制图》2019,34(4):348-367

This study evaluates and compares landslide susceptibility maps of the Baxie River basin, Gansu Province, China, using three models: evidential belief function (EBF), certainty factor (CF) and frequency ratio (FR). First, a landslide inventory map is constructed from satellite image interpretation and extensive field data. Second, the study area is partitioned into 17,142 slope units, and modelled using nine landslide influence parameters: elevation, slope angle, slope aspect, relief amplitude, cutting depth, gully density, lithology, normalized difference vegetation index and distance to roads. Finally, landslide susceptibility maps are presented based on EBF, CF and FR models and validated using area under curve (AUC) analysis. The success rates of the EBF, CF and FR models are 0.8038, 0.7924 and 0.8088, respectively, while the prediction rates of the three models are 0.8056, 0.7922 and 0.7989, respectively. The result of this study can be reliably used in land use management and planning.  相似文献   

杭州市城市建筑区夏季地表温度特征分析   总被引：1，自引：0，他引：1  

顾春墚  唐伟  桑玉田 《测绘与空间地理信息》2019,42(4):48-51

以浙江省杭州市为研究对象,选择Landsat-8遥感数据和Jiménez-Muoz单通道算法进行地表温度遥感反演,同时结合地理国情数据分类结果数据,对杭州市城市建筑区域地表温度进行综合分析。通过反演的地表温度结果和区域统计分析,得出了杭州市2016夏季地表温度的空间分布特征。结果表明:杭州市城区部分的拱墅区、下城区、江干区、上城区和滨江区等区域,城市建筑温度整体较高;余杭区中部、萧山区中部和东北部、西湖区北部区域城市建筑温度较高;城区西部建筑区域温度相对较低。地表温度的极大值出现在拱墅区,为55.64℃;极小值出现在余杭区,为25.68℃。  相似文献   

中美商品贸易格局及网络特征演变   总被引：1，自引：1，他引：0  

周政可  梁育填 《地理科学进展》2019,38(10):1633-1642

中美作为世界上最大的2个经济体,中美贸易格局及其发展演化对全球经济的发展具有深刻的影响,然而,中美贸易格局特征以及贸易产品网络地位与演变当前还没有得到充分揭示。因此,论文基于联合国商品贸易数据,采用描述性统计分析和社会网络分析方法,对2001—2017年中美两国的贸易发展历程、产品结构、产品贸易网络进行分析研究。研究发现：① 在贸易联系方面,2001—2017年中美双边进出口贸易额不断上升,贸易联系不断增强。② 出口产品结构方面,中国对美国的出口产品类型主要是机械设备、纺织服装等产品,产品结构没有发生大的改变;美国对中国的出口产品类型主是机械设备、运输设备、植物产品和化工产品,近年来机电产品占比有所下降,运输设备产品比例上升。③ 主要产品贸易网络方面,以电子信息产品为例,一方面度中心性指标反映出中国在网络中影响力迅速增强,是电子信息产品全球贸易网络的核心成员国;另一方面在中介中心度与接近中心度2个指标上中国与美国仍存在差距,电子信息产业核心竞争力有待加强,在新一轮产业变革中应投入更多物质与精力用于产业链高端技术的研发与开拓。  相似文献   

系泊定位状态下半潜式浮体波浪爬升性能试验研究     

李亚美  刘义杰  朱玉田  刘钊 《海洋通报》2021,40(5)

随着深海油气田的快速发展,新兴的浮式生产系统,尤其是半潜式平台,由于具有性能优良、运动响应小、工作水深适用范围广、抗风浪荷载能力强等优点,在工程实际中得到快速的发展。在半潜式平台设计过程中,气隙和斜浪作用下的波浪爬升问题对其安全性能的影响至关重要。通过采用系泊定位状态下的四立柱半潜式平台进行波浪爬升实验,对平台不同位置进行全方位的监测,而后对测量数据进行分析,得出关于海浪对半潜式平台气隙响应的影响和相关规律,为半潜式平台的设计提供参考。  相似文献   

具反应扩散项的脉冲时滞Cohen-Grossberg神经网络的稳定性     

张雨田  章旻慧 《南京气象学院学报》2012,4(3):213-219

讨论了一类具反应扩散项的脉冲变时滞Cohen-Grossberg神经网络在Neu-mann边界条件下的稳定性.通过构造分片连续的Lyapunov函数,结合Neumann特征值问题,并利用Gronwall-Bellman脉冲积分不等式,得到了新的与反应扩散项和时滞有关的保证平衡点全局指数稳定性的代数判据.  相似文献   

Changes in storm tracks and energy transports in a warmer climate simulated by the GFDL CM2.1 model   总被引：1，自引：0，他引：1  

Yutian Wu  Mingfang Ting  Richard Seager  Huei-Ping Huang  Mark A. Cane 《Climate Dynamics》2011,37(1-2):53-72

Storm tracks play a major role in regulating the precipitation and hydrological cycle in midlatitudes. The changes in the location and amplitude of the storm tracks in response to global warming will have significant impacts on the poleward transport of heat, momentum and moisture and on the hydrological cycle. Recent studies have indicated a poleward shift of the storm tracks and the midlatitude precipitation zone in the warming world that will lead to subtropical drying and higher latitude moistening. This study agrees with this key feature for not only the annual mean but also different seasons and for the zonal mean as well as horizontal structures based on the analysis of Geophysical Fluid Dynamics Laboratory (GFDL) CM2.1 model simulations. Further analyses show that the meridional sensible and latent heat fluxes associated with the storm tracks shift poleward and intensify in both boreal summer and winter in the late twenty-first century (years 2081?C2100) relative to the latter half of the twentieth century (years 1961?C2000). The maximum dry Eady growth rate is examined to determine the effect of global warming on the time mean state and associated available potential energy for transient growth. The trend in maximum Eady growth rate is generally consistent with the poleward shift and intensification of the storm tracks in the middle latitudes of both hemispheres in both seasons. However, in the lower troposphere in northern winter, increased meridional eddy transfer within the storm tracks is more associated with increased eddy velocity, stronger correlation between eddy velocity and eddy moist static energy, and longer eddy length scale. The changing characteristics of baroclinic instability are, therefore, needed to explain the storm track response as climate warms. Diagnosis of the latitude-by-latitude energy budget for the current and future climate demonstrates how the coupling between radiative and surface heat fluxes and eddy heat and moisture transport influences the midlatitude storm track response to global warming. Through radiative forcing by increased atmospheric carbon dioxide and water vapor, more energy is gained within the tropics and subtropics, while in the middle and high latitudes energy is reduced through increased outgoing terrestrial radiation in the Northern Hemisphere and increased ocean heat uptake in the Southern Hemisphere. This enhanced energy imbalance in the future climate requires larger atmospheric energy transports in the midlatitudes which are partially accomplished by intensified storm tracks. Finally a sequence of cause and effect for the storm track response in the warming world is proposed that combines energy budget constraints with baroclinic instability theory.  相似文献   

金矿综合信息预测知识抽取机制     

刘超  王于天 《吉林大学学报(地球科学版)》1995,(1)

论述了金矿综合信息预测知识库建造中所使用的知识抽取机制，即从专家知识源获取知识，表示为知识库形式的过程和方法。知识抽取是一个多任务过程，不仅要分析领域知识的特点及知识库的形式，而且还要进行相应的知识抽取任务分析及方法研究。本文章给出了一种抽取方法，为知识工程师对专家知识的抽取提供了良好的结构，并使所抽取的知识更有意义。该方法对分类型知识的获取具有一定的适用性。  相似文献   

Therm odynamics of Diagenetic Fluid and Fluid／Mineral Reactions in the Eogene Xingouzui Formation,Oil Field T,Jianghan Basin     

Ni Shijun  Luo Yutian  Liu Lihua  Wang Xuben  Li Sue  Luo Yangdi  Han Dingrong 《中国地球化学学报》1994,13(3):193-201

This study focuses on the thermodynamics of diagenetic fluid from the Eogene Xingouzui Formation which represents the most important reservoir in Field Oil T in the Jianghan Basin. The measured homogenization temperatures (110–139 °C) of fluid inclusions in diagenetic minerals fell within the range of 67 –155 °C at the middle diagenetic stage. The pressure of diagenetic fluid is estimated at 10.2 –56 MPa. The activity of ions in the fluid shows a tendency of Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ > Fe³⁺ > Fe²⁺ for cations, and HCO ₃ ⁻ > SO ₄ ²⁻ > F⁻ > Cl⁻ > CO ₃ ²⁻ for anions. For the gaseous facies, there is a tendency of CO₂> CO> H₂S> CH₄> H₂. According to the thermodynamic calculations, the pH and Eh of the fluid are 5.86–6.47 and −0.73–−0.64V, respectively. As a result of the interaction between such a diagenetic fluid and minerals in the sediments, feldspars were dissolved or alterated by other minerals. The clay mineral kaolinite was instable and hence was replaced by illite and chloritoid. This project was jointly funded by the National Natural Science Foundation of China (49133080) and the Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences.  相似文献   

中国企业投资东南亚国家的影响因素分析——基于企业所有权差异的视角   总被引：3，自引：3，他引：0  

梁育填  黄慧怡  刘逸  周政可 《地理科学》2018,38(5):645-653

以中国企业2005~2015年对东南亚直接投资的项目作为研究样本,分析国有企业和民营企业在东南亚直接投资的国家选择和影响因素。研究表明,国有企业不回避政治风险较高的国家,倾向于开拓新的国家市场;相反,民营企业倾向投资政治风险低的国家,投资与中国贸易联系紧密、相对市场规模较大以及劳动力成本较低的国家。基于国有企业和民营企业对东南亚直接投资影响因素的差异,为中国对东南亚直接投资提出政策建议。  相似文献   

鲁西北一次持续性暴雨成因分析   总被引：4，自引：2，他引：2  

杨学斌  代玉田  陈华凯  张优琴 《气象科学》2016,36(2):275-282

利用地面自动气象站、NCEP 1°×1°和FY2E反演T_(BB)等资料,对2012年7月31日—8月1日发生在山东一次持续的区域性暴雨进行分析和研究。结果表明,(1)在副高稳定的形势下,低层切变线、地面冷锋是造成暴雨的主要天气系统。(2)低层锋生强迫激发了非地转垂直环流,上升气流加强,雨强增大,上升支的建立到强降水开始间隔约6 h。(3)暴雨区925 hPa湿斜压项在强降水时为负值,其增强应为低层锋生作用造成的。雨区范围和雨强随湿斜压项增强而增大。(4)对流单体的生成和加强影响降水落区和雨强,增强的单体合并时雨强最强。T_(BB)中心区位于低层切变线与锋面右侧,强降水位于两者之间。(5)地面辐合线与T_(BB)中心基本重合,辐合线左侧气旋性弯曲处与T_(BB)中心区后侧的等值线梯度大值区位置一致,强降水则出现在两者重叠处。(6)干线与辐合线是此次强降水的重要中尺度系统,干线始终落后于辐合线,其分布对暴雨落区有一定的指示意义。  相似文献