MODIS数据水体识别指数的识别效果比较分析   总被引：4，自引：1，他引：3  

廖程浩  刘雪华 《国土资源遥感》2008,19(4):22-26

在光谱分析的基础上,应用不同水体指数对MODIS数据进行水体信息识别,并对其应用性能进行比较分析。结果表明,混合水 体指数（CIWI）是较理想的水体识别指数。若以反射率计算,并以0为判别阈值,则该指数的提取常数C的最佳取值为-0.85。 就目前的研究成果来看,MODIS数据还不太适合用于小型水体的识别。  相似文献   

On evaluating the stability of the Baiyian ancient landslide in the Three Gorges Reservoir area,Yangtze River: a geological history analysis   总被引：1，自引：0，他引：1  

Xiao Li  Qiulin Liao  Sijing Wang  Jishan Liu  Souting Lee 《Environmental Geology》2008,55(8):1699-1711

Numerous landslides have occurred during the construction of the Three Gorges Reservoir of the Yangtze River. Although the underlying causal factor of these landslides was heavy rainfall, the construction process was the trigger of some of them. We report here a systematic study aimed at reconstructing the geological history of an ancient landslide and, based on our results, an evaluation of the role of the history on current landslide stability. Data from detailed field surveys and the studies on geological dating revealed that the Baiyian landslide was composed of five structural parts of different geological ages, such as a sliding belt, disturbed rocks, ancient colluvium, alluvium of the Yangtze River and slope wash. The succession of ancient climates, terraces and tectonic processes in the study area were examined from 300 ka ago. The evolutionary history of the Baiyian ancient landslide can be divided into five distinct stages: development, occurrence, deposition, collapse and disintegration. Some parts of the ancient landslide are currently prone to instability due to the combination effects of heavy rainfall and construction of the reservoir.  相似文献   

宁夏电力网地理信息系统     

林向军  田锋 《现代测绘》2008,31(1):47-48

如何利用高科技的手段--地理信息技术(GIS)为人类社会的基础建设提供科学的决策依据,是测绘行业的一个新课题.本文讲述了宁夏电力网地理信息系统的架构和应用功能.  相似文献   

A Clustering‐Based Approach to the Capacitated Facility Location Problem1     

Ke Liao  Diansheng Guo 《Transactions in GIS》2008,12(3):323-339

This research develops a clustering‐based location‐allocation method to the Capacitated Facility Location Problem (CFLP), which provides an approximate optimal solution to determine the location and coverage of a set of facilities to serve the demands of a large number of locations. The allocation is constrained by facility capacities – different facilities may have different capacities and the overall capacity may be inadequate to satisfy the total demands. This research transforms this special location‐allocation problem into a clustering model. The proposed approach has two parts: (1) the allocation of demands to facilities considering capacity constraints while minimizing the cost; and (2) the iterative optimization of facility locations using an adapted K‐means clustering method. The quality of a location‐allocation solution is measured using an objective function, which is the demand‐weighted distance from demand locations to their assigned facilities. The clustering‐based method is evaluated against an adapted Genetic Algorithm (GA) alternative, which integrates the allocation component as described above but uses GA operations to search for ‘optimal’ facility locations. Experiments and evaluations are carried out with various data sets (including both synthetic and real data).  相似文献   

渤海湾盆地歧口凹陷沙河街组一段下亚段湖相白云岩及其与海相白云岩的差异   总被引：8，自引：0，他引：8  

廖静  董兆雄  翟桂云  周立英  范鹏 《海相油气地质》2008,13(1):18-24

渤海湾盆地歧口凹陷古近系沙河街组一段下亚段湖相白云岩主要为颗粒白云岩和泥晶白云岩两大类,常与泥质岩成薄互层或与其他碳酸盐岩互层产出。该湖相白云岩有序度较低,类似于海相准同生白云岩;Mg/Ca值偏离正常的化学计量值,具有富钙特征,说明其为快速交代的产物;碳氧同位素、Z值分析结果则反映了湖水的咸化程度较高。根据低海平面期蒸发浓缩盐水在湖底形成密度层并向灰质沉积层中回流渗透导致白云石化发生的机理,建立了歧口凹陷沙一下亚段湖相白云岩的成因模式。湖相白云岩的分布特征及其与海相白云岩的差异分析表明,湖相白云岩具有分布面积小、白云石化作用不彻底等特征,油气储集性能较为局限。  相似文献   

利用HBV水文预报模型推算贺江流域洪水致灾临界雨量     

黄卓  黄远盼  韦小雪  廖雪萍  李耀先 《气象科技》2018,46(4):738-743

利用逐日气象水文资料,针对贺江流域进行HBV水文模型率定与验证,获得降水-流量关系,结合广西贺州市信都水文站的水位-流量关系,推算得到3个洪水风险预警级别对应的临界雨量,并通过2次历史洪水过程,检验该临界雨量在暴雨洪涝灾害风险预警中的应用效果。结果表明:(1)由HBV水文模型确定的贺江流域3个不同洪水风险等级下24h、48h的致灾临界雨量,预警效果较好;(2)HBV模型能很好地反映降水对贺江水文过程的影响,可为贺江流域暴雨洪涝灾害防御工作提供决策参考。  相似文献   

武汉市一次对流梅雨暴雨过程诊断分析     

张端禹  崔春光  廖移山 《气象科技》2018,46(3):594-604

2016年7月5—6日武汉市发生对流梅雨暴雨,出现严重城市内涝。分析对流云团活动、天气系统与物理量演变,结果表明:(1)对流云团来自江汉平原东部,暴雨前期对流云团合并发生在2个β云团之间,中期2个β云团先后与1个α云团合并,后期对流云团无明显合并,虽有向西的指状对流云生成,武汉市强降雨还是开始减弱。(2)暴雨发生在200hPa南亚高压东伸脊北侧,500hPa副热带高压在江南加强西进过程中,500hPa纬向切变转为低槽东移,850hPa江汉平原低涡则是迴旋少动,高空偏北风急流左侧水汽辐散与偏南风低空急流前方水汽辐合耦合有利于启动强降雨。(3)武汉站200~850hPa,500~850hPa风垂直切变明显,400hPa干空气入侵,共同触发了强降雨。  相似文献   

广西霾天气系统分型   总被引：1，自引：0，他引：1  

廖国莲  郑凤琴  曾鹏  莫雨淳 《气象科技》2018,46(1):149-154

利用2009—2013年NCEP再分析资料和广西14个地级市的历史气象资料,通过天气学方法对广西233个霾日对应的天气系统进行了分类,将形成广西霾日的天气系统分成冷高压脊控制型、入海高压后部型、低压槽型、均压场型、冷锋前部型、副高控制型、静止锋暖区型和热带气旋外围型共8种类型,研究了各类型天气系统的特点及其在广西霾形成中的作用。结果表明:冷高压脊控制型、入海高压后部型、均压场型和低压槽型是4种主要的环流型,造成的广西霾日较多,静止锋暖区型和热带气旋外围型造成的霾日较少;冷高压脊控制型和副高控制型的霾过程持续时间比较长,冷锋前部型的霾过程持续时间最短;地面风速较小,中低空为下沉气流是出现霾日时各类天气型的共同特征。  相似文献   

A fine-grained perspective on the robustness of global cargo ship transportation networks   总被引：2，自引：0，他引：2  

Peng Peng  Shifen Cheng  Jinhai Chen  Mengdi Liao  Lin Wu  Xiliang Liu  Feng Lu 《地理学报(英文版)》2018,28(7):881-899

The robustness of cargo ship transportation networks is essential to the stability of the world trade system. The current research mainly focuses on the coarse-grained, holistic cargo ship transportation network while ignoring the structural diversity of different sub-networks. In this paper, we evaluate the robustness of the global cargo ship transportation network based on the most recent Automatic Identification System (AIS) data available. First, we subdivide three typical cargo ship transportation networks (i.e., oil tanker, container ship and bulk carrier) from the original cargo ship transportation network. Then, we design statistical indices based on complex network theory and employ four attack strategies, including random attack and three intentional attacks (i.e., degree-based attack, betweenness- based attack and flux-based attack) to evaluate the robustness of the three typical cargo ship transportation networks. Finally, we compare the integrity of the remaining ports of the network when a small proportion of ports lose their function. The results show that 1) compared with the holistic cargo ship transportation network, the fine-grain-based cargo ship transportation networks can fully reflect the pattern and process of global cargo transportation; 2) different cargo ship networks behave heterogeneously in terms of their robustness, with the container network being the weakest and the bulk carrier network being the strongest; and 3) small-scale intentional attacks may have significant influence on the integrity of the container network but a minor impact on the bulk carrier and oil tanker transportation networks. These conclusions can help improve the decision support capabilities in maritime transportation planning and emergency response and facilitate the establishment of a more reliable maritime transportation system.  相似文献   

Assessment and determinants of per capita household CO<Subscript>2</Subscript> emissions (PHCEs) based on capital city level in China     

Lina Liu  Jiansheng Qu  Zhiqiang Zhang  Jingjing Zeng  Jinping Wang  Liping Dong  Huijuan Pei  Qin Liao 《地理学报(英文版)》2018,28(10):1467-1484

Household CO₂ emissions were increasing due to rapid economic growth and different household lifestyle. We assessed per capita household CO₂ emissions (PHCEs) based on different household consuming demands (including clothing, food, residence, transportation and service) by using provincial capital city level survey data in China. The results showed that: (1) there was a declining trend moving from eastward to westward as well as moving from northward to southward in the distribution of PHCEs. (2) PHCEs from residence demand were the largest which accounted for 44% of the total. (3) Correlation analysis and spatial analysis (Spatial Lag Model (SLM) and Spatial Error Model (SEM)) were used to evaluate the complex determinants of PHCEs. Per capita income (PI) and household size (HS) were analyzed as the key influencing factors. We concluded that PHCEs would increase by 0.2951% and decrease by 0.5114% for every 1% increase in PI and HS, respectively. According to the results, policy-makers should consider household consuming demand, income disparity and household size on the variations of PHCEs. The urgency was to improve technology and change household consuming lifestyle to reduce PHCEs.  相似文献