Dynamic land use change simulation using cellular automata with spatially nonstationary transition rules

The dynamic relationships between land use change and its driving forces vary spatially and can be identified by geographically weighted regression (GWR). We present a novel cellular automata (GWR-CA) model that incorporates GWR-derived spatially varying relationships to simulate land use change. Our GWR-CA model is characterized by spatially nonstationary transition rules that fully address local interactions in land use change. More importantly, each driving factor in our GWR model contains effects that both promote and resist land use change. We applied GWR-CA to simulate rapid land use change in Suzhou City on the Yangtze River Delta from 2000 to 2015. The GWR coefficients were visualized to highlight their spatial patterns and local variation, which are closely associated with their effects on land use change. The transition rules indicate low land conversion potential in the city’s center and outer suburbs, but higher land conversion potential in the inner near suburbs along the belt expressway. Residual statistics show that GWR fits the input data better than logistic regression (LR). Compared with an LR-based CA model, GWR-CA improves overall accuracy by 4.1% and captures 5.5% more urban growth, suggesting that GWR-CA may be superior in modeling land use change. Our results demonstrate that the GWR-CA model is effective in capturing spatially varying land transition rules to produce more realistic results, and is suitable for simulating land use change and urban expansion in rapidly urbanizing regions.     

用于海上溢油监测的航海雷达图像降噪技术研究

航海雷达溢油监测技术具有大范围目标探测、工作方式灵活、能够适应恶劣天气的优势。而海上溢油监测技术应用的航海雷达原始图像数据中,含有大量的同频干扰、斑点、假目标等噪声,处理上述噪声是航海雷达海上溢油监测技术研究的首要工作。本文基于先锁定噪声位置,再消除噪声的思想,提出了一种有效的航海雷达原始回波图像的降噪技术。以大连716溢油事故中采集得到的数据进行试验,并分析处理结果,这种方法不仅能够很好地消除干扰噪声,而且能够有效地保护航海雷达原始回波图像中的海浪信息,为溢油监测技术研究提供了良好的数据基础。     

东营凹陷沙河街组碳酸盐胶结物成因机制

正碳酸盐矿物是砂岩储层中主要的成岩产物之一。碳酸盐胶结物较为活跃,其溶蚀及沉淀广泛发育于砂岩储层内。碳酸盐的溶蚀及沉淀是砂岩储层改造的重要成因之一。明确碳酸盐胶结物的成因机制对预测深部储层具有重要的意义。本次研究,采用铸体薄片及扫描电镜观察,明确碳酸盐胶结物的产状。对不同产状碳酸盐胶结物的分布、     

新书简介——《动物世界的先驱——中国第一个候选“金钉子”梅树村剖面实证记录及对比》

正唐烽,陈建书,任留东,高林志,华洪, 等. 著. 2021. 动物世界的先驱——中国第一个候选"金钉子"梅树村剖面实证记录及对比. 昆明: 云南科技出版社:1～498页。20世纪70 年代,云南晋宁梅树村震旦系—寒武系界线层型剖面的发现,彻底改变了据此划分寒武系和寒武系以前地层的标志,它在当时即闻名于全球地学界。它也是中国改革开放以后,第一个参加的国际地层划分对比合作计划(IGCP 项目)、参与国际竞争"金钉子"     

Urbanization impacts on flood risks based on urban growth data and coupled flood models

Natural Hazards - Urbanization increases regional impervious surface area, which generally reduces hydrologic response time and therefore increases flood risk. The objective of this work is to...     

塔里木盆地顺北地区11号走滑断裂带变形及其活动特征

塔里木盆地顺北地区发育大量走滑断裂带,并对油气的运聚成藏有重要控制作用。以顺北西部地区地震资料为基础,对顺北11号走滑断裂带的几何变形特征、活动性、活动期次及其形成机制等进行了分析。顺北11号走滑断裂带整体呈NNW走向延伸,具有垂向分层性和平面分段性。断裂带北段主体为压扭和张扭交互段,中段为两条次级断层控制的拉分地堑,南段由数条分支断层构成马尾状构造。顺北11号断裂带整体活动性由北向南减弱,运动学标志显示是一条右旋走滑断层。顺北11号断裂带主要经历了晚奥陶世和晚志留世-中泥盆世两期活动,部分地区的活动持续到石炭纪。顺北11号走滑断裂带的活动性和运动学特征与塔北地区NNW走向的走滑断裂体系比较相似,而不同于塔中地区的NE向左行走滑断裂体系。顺北11号走滑断裂带的形成主要受控于塔里木盆地北部天山洋多期俯冲挤压而产生的自北向南的挤压应力,断裂自北向南扩展延伸,类似于顺北5号走滑断裂带的北段。     

砾石在分析盆地物源区迁移与湖岸线演化中的作用*

中国中西部盆地的盆山结合部位,勘探程度较低、钻井少、地震成像复杂,致使利用传统的地震相、测井相、岩心资料等研究原型盆地岩相古地理特征较为困难。基于露头中巨厚砾岩发育层段对应盆地内储集层平面展布范围最广这一认识,运用“将今论古”方法,建立南天山前现代冲积扇、扇三角洲平原、河流等沉积体系中砾石与搬运距离关系,以及不同沉积相类型中砾石发育产状与湖岸线远近关系,定量计算了准噶尔盆地多条重点剖面侏罗系—白垩系现今位置与沉积物源区和湖岸线演化的距离,恢复了侏罗纪—白垩纪物源区范围与湖岸线演化过程。认为侏罗纪—早白垩世砂砾岩储集体向盆地内延伸范围最大时期的湖岸线,明显与现今盆地边缘线有一向西北方向敞开的夹角,该认识对在编制岩相古地理图过程中以盆地边缘线即为湖岸线的观念提出了不同见解,为恢复准南等低勘探程度区原型盆地的岩相古地理特征、预测有利储集体的展布提供参数依据。建立的刻画物源区变化和湖岸线迁移的定量评价方法与参数,是对传统沉积学研究的有益补充。     

确定砂土动剪切模量和阻尼比的方法对比

确定土体动剪切模量的常用方法有规范法、Kumar法和自相关函数法,确定相应阻尼比的方法有规范法、Das and Luo法、Kokusho法、Kumar法和互相关函数法,为了分析不同方法所产生差异,实现定量化对比分析,笔者以福建标准砂（粒径为0.5~1.0 mm）为研究对象,采用不排水的应力控制动三轴试验,探讨不同的确定土体动剪切模量和阻尼比方法的差异性,并给出了不同土体条件建议选用的方法。结果表明：1）3种方法确定动剪切模量的结果有一定的差异,随剪应变的增大结果的差异逐渐增大,有效围压对结果的差异性有所影响,当剪应变为4×10^-3,有效围压为100 kPa时,3种方法差异显著,相对误差最大接近20%;2）而5种方法确定阻尼比的结果差异显著,随着剪应变的增大,5种方法确定的阻尼比相对误差大体上均在迅速减小,只有规范法在有效围压为100 kPa时,其相对误差有较小的增大趋势;5种方法中,Kumar法确定的阻尼比最接近平均阻尼比,互相关函数法远高于平均阻尼比,Das and Luo法和Kokusho法确定的阻尼比基本一致但低于平均阻尼比。建议以后的工程应用中,加载方式为应力控制时,可采用自相关函数法确定动剪切模量,采用Kumar法确定阻尼比,二者确定的动剪切模量和阻尼比均最接近平均值。     

某建设用地土壤污染状况调查与评价

以安徽某块建设用地为研究对象,结合企业生产历史,识别地块疑似污染区域以及关注的污染物,参照国家技术要求布设土壤及地下水监测点.通过现场调查与采样测试,研究土壤及地下水中监测因子浓度及分布特征,对比国家现行标准分析得出检测因子未存在超标情况,评价地块环境风险可接受.     

Numerical simulation and evaluation of the fracturing and tight gas production with a new dimensionless fracture conductivity (FCD) model

Hydraulic fracturing is an essential technology for the development of unconventional resources such as tight gas. The evaluation of the fracture performance and productivity is important for the design of fracturing operations. However, the traditional dimensionless fracture conductivity is too simple to be applied in real fracturing operations. In this work, we proposed a new model of dimensionless fracture conductivity (F_CD), which considers the irregular fracture geometry, proppant position and concentration. It was based on the numerical study of the multistage hydraulic fracturing and production in a tight gas horizontal well of the North German Basin. A self-developed full 3D hydraulic fracturing model, FLAC3D^plus, was combined with a sensitive/reliability analysis and robust design optimization tool optiSLang and reservoir simulator TMVOCMP to achieve an automatic history matching as well as simulation of the gas production. With this tool chain, the four fracturing stages were history matched. The simulation results show that all four fractures have different geometry and proppant distribution, which is mainly due to different stress states and injection schedule. The position and concentration of the proppant play important roles for the later production, which is not considered in the traditional dimensionless fracture conductivity F_CD. In comparison, the newly proposed formulation of F_CD could predict the productivity more accurately and is better for the posttreatment evaluation.