Incorporating spatial interaction patterns in classifying and understanding urban land use   总被引：4，自引：0，他引：4  

Xi Liu  Chaogui Kang  Li Gong 《International journal of geographical information science》2016,30(2):334-350

Land use classification has benefited from the emerging big data, such as mobile phone records and taxi trajectories. Temporal activity variations derived from these data have been used to interpret and understand the land use of parcels from the perspective of social functions, complementing the outcome of traditional remote sensing methods. However, spatial interaction patterns between parcels, which could depict land uses from a perspective of connections, have rarely been examined and analysed. To leverage spatial interaction information contained in the above-mentioned massive data sets, we propose a novel unsupervised land use classification method with a new type of place signature. Based on the observation that spatial interaction patterns between places of two specific land uses are similar, the new place signature improves land use classification by trading off between aggregated temporal activity variations and detailed spatial interactions among places. The method is validated with a case study using taxi trip data from Shanghai.  相似文献   

安徽铜官山铜-铁-金-硫矿床的地球化学特征   总被引：3，自引：0，他引：3       下载免费PDF全文

李红阳  李英杰  康桂玲  曹积飞  杨竹森  侯增谦  蒙义峰 《地质科学》2008,43(2):370-376

铜官山铜-铁-金-硫矿床发育上部层状矿体和下部网脉状矿体,地球化学特征呈现出明显的垂向变化和二元结构性.从下部网脉状矿化岩石到上部层状矿石,CaO、MgO、Fe2O3、FeO等含量和δ18O值总体逐渐增高,SiO2、Al2O3,、TiO2、K2O、Na2O、REE等含量和流体包裹体温度(341.9 ℃→178.0 ℃)及δ34S 值总体逐渐降低.黄铁矿δ34S值为( 2.1～ 7.9) ‰,上部层状块状矿石中方解石和石英δ18O平均值为 13.9‰,下部网脉状矿化岩(矿)石中脉石英或全岩δ18O平均值为 11.7‰.  相似文献   

A distributed water-heat coupled model for mountainous watershed of an inland river basin of Northwest China (I) model structure and equations   总被引：1，自引：0，他引：1  

Ren-sheng Chen  Shi-hua Lu  Er-si Kang  Xi-bin Ji  Zhihui Zhang  Yong Yang  Wenwu Qing 《Environmental Geology》2008,53(6):1299-1309

It is absolutely necessary to quantify the hydrological processes in earth surface by numerical models in the cold regions where although most Chinese large rivers acquire their headstreams, due to global warming, its glacier, permafrost and snow cover have degraded seriously in the recent 50 years. Especially in an arid inland river basin, where the main water resources come from mountainous watershed, it becomes an urgent case. However, frozen ground’s impact to water cycle is little considered in the distributed hydrological models for a watershed. Took Heihe mountainous watershed with an area of 10,009 km², as an example, the authors designed a distributed heat-water coupled (DWHC) model by referring to SHAW and COUP. The DWHC model includes meteorological variable interception model, vegetation interception model, snow and glacier melting model, soil water-heat coupled model, evapotransporation model, runoff generation model, infiltration model and flow concentration model. With 1 km DTM grids in daily scale, the DWHC model describes the basic hydrological processes in the research watershed, with 3∼5 soil layers for each of the 18 soil types, 9 vegetation types and 11 landuse types, according to the field measurements, remote sensing data and some previous research results. The model can compute the continuous equation of heat and water flow in the soil and can estimate them continuously, by numerical methods or by some empirical formula, which depends on freezing soil status. However, the model still has some conceptual parameters, and need to be improved in the future. This paper describes only the model structure and basic equations, whereas in the next papers, the model calibration results using the data measured at meteorological stations, together with Mesoscale Model version 5 (MM5) outputs, will be further introduced.  相似文献   

Response of Glacier and Lake Covariations to Climate Change in Mapam Yumco Basin on Tibetan Plateau during 1974–2003     

叶庆华  姚檀栋  陈锋  康世昌  张雪芹  王毅 《中国地质大学学报(英文版)》2008,19(2):135-145

The study of spatial and temporal covariances of glaciers and lakes would help us to understand the impact of climate change within a basin in Tibet. This study focuses on glacier and lake variations in the Mapam Yumco(玛旁雍错)Basin (covering 7 786.44 km2)by Integrationg series of spatial data from topographic maps and digital satellite images at four different times 1974, 1990, 1999,and 2003. The results indicate that (1) decreased lakes, retreated glaciers, enlarged lakes and advanced glaciers co-exist in the basin during the last 30 years; (2) glacier recession was accelerated in recent years due to the warmer climate; (3) lake areas in the basin are both reduced and enlarged by an accelerated speed with more water supplies from speeding melt glaciers or frozen ground in the last three decades.  相似文献   

一种土-岩混合边坡的稳定性分析计算方法     

张莲花  唐凌翔  罗康 《岩土工程技术》2008,22(3):119-122

土-岩混合边坡是指工程中常见的上部由土和岩石全风化层组成,下部由岩石组成的边坡.针对现行相关规范规程中未给出土-岩混合边坡稳定性分析具体方法的现实问题,结合某工程实例,提出了对坡体上部土和强风化层采用圆弧法滑动法分析、下部岩石依据结构面组合确定危险面,总体采用传递系数法进行稳定性分析的思路及具体方法,可为岩质非顺向的土-岩混合边坡的稳定性分析提供参考.  相似文献   

Impact of Altered Land Use on the Hydrology of Urban Territories     

K. Kang  J. Lee  J. A. Chun  D. Timlin 《Russian Meteorology and Hydrology》2018,43(3):197-202

This paper describes the impact of altered land use on urban flooding in Northwest Indiana over a 10-year time span between 1992 and 2001. The studied watershed, the Great Calumet basin, is located on the south shore of Lake Michigan, which is well known as a highly industrialized area. The flood peaks and the time-to-peak values are used to analyze the flooding problems of the study area. The study uses a Hydrologic Engineering Center for Hydrologic Modeling System (HEC-HMS) model to explore the change in land use represented by Curve Number (CN). The model parameters are calibrated using archived raintall data available in National Climatic Data Center (NCDC) and United States Geological Survey (USGS) Instantaneous Data Archive (IDA). All four simulations show that the peak flow of simulated hydrographs in the terrain conditions of 2001 is by 22% higher than that in the terrain of 1992. The paper concludes with the results of simulation analyses that can be used to remedy flooding problems in the study area.  相似文献   

Development of an Observation Processing Package for Data Assimilation in KIAPS     

Jeon-Ho Kang  Hyoung-Wook Chun  Sihye Lee  Ji-Hyun Ha  Hyo-Jong Song  In-Hyuk Kwon  Hyun-Jun Han  Hanbyeol Jeong  Hui-Nae Kwon  Tae-Hun Kim 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):303-318

A new observation processing system, the Korea Institute of Atmospheric Prediction Systems (KIAPS) Package for Observation Processing (KPOP), has been developed to provide optimal observation datasets to the data assimilation (DA) system for the Korean Integrated Model, KIM. This paper presents the KPOP’s conceptual design, how the principal modules have been developed, and some of their preliminary results. Currently, the KPOP is capable of processing almost all observation types used by the Korea Meteorological Administration (KMA) and some new observation types that have a positive impact in other operational centers. We have developed an adaptive bias correction (BC) method that only uses the background of the analysis time and selects the best observations through the consecutive iteration of BC and quality control (QC); it has been verified that this method will be the best suited for the KIAPS DA system until the development of variational BC (VarBC) has been completed. The requirement of considering the radiosonde balloon drift in the DA according to the increase of spatial resolution of the NWP model was accounted for using a balloon drift estimation method that considers the pressure difference and wind speed; thus the distance error was less than 1% in the sample test. Some kind of widely used methods were tested for height adjustment of the SURFACE observation, and a new method for temperature adjustment was outlined that used the correlation between temperature and relative humidity. In addition, three types of map projection were compared: the cubed-sphere (CS), equidistance (ED), and equirectangular (ER) projection for thinning. Data denial experiments were conducted to investigate how the KPOP affected the quality of the analysis fields in the three-dimensional variational data assimilation system (3D-Var). Qualified observations produced by the KPOP had a positive impact by reducing the analysis error.  相似文献   

地理系统模型研究进展     

彭书时  朴世龙  于家烁  刘永稳  汪涛  朱高峰  董金玮  缪驰远 《地理科学进展》2018,37(1):109-120

地理系统是多圈层交互的复杂巨系统。地理系统模型是理解和预测不同尺度地理系统格局和过程变化最重要的研究方法。地理系统模型作为可持续发展科学决策必需的工具,是自然地理学重要的研究方向。过去几十年来,在全球变化等全球性重大环境问题和人类科学决策需求的推动下,地理系统模型虽然发展迅速,但还不足以准确地模拟和预测复杂人地耦合系统。本文分别从模型原理、框架和尺度等方面回顾与梳理了地理系统模型从单要素到多要素、从统计到过程、从静态到动态、从单点到区域和全球尺度模拟等发展历程,并总结了地理系统模型对发展人类—自然耦合系统以及模型—数据融合系统的趋势。发展中国的地理系统模型将有助于中国和全球可持续发展的科学决策。  相似文献   

Effects of freeze–thaw cycles on soil N_2O concentration and flux in the permafrost regions of the Qinghai–Tibetan Plateau     

ShengYun Chen  Qian Zhao  WenJie Liu  Zhao Zhang  Shuo Li  HongLin Li  ZhongNan Nie  LingXi Zhou  ShiChang Kang 《寒旱区科学》2018,10(1):69-79

Nitrous oxide(N_2 O) is one of the most important greenhouse gases in the atmosphere; freeze–thaw cycles(FTCs) might strongly influence the emission of soil N_2 O on the Qinghai–Tibetan Plateau(QTP). However, there is a lack of in situ research on the characteristics of soil N_2 O concentration and flux in response to variations in soil properties caused by FTCs.Here, we report the effect of FTC-induced changes in soil properties on the soil N_2 O concentration and flux in the permafrost region of the higher reaches of the Shule River Basin on the northeastern margin of the QTP. We measured chemical properties of the topsoil, activities of soil microorganisms, and air temperature(AT), as well as soil N_2 O concentration and flux, over an annual cycle from July 31, 2011, to July 30, 2012. The results showed that soil N_2 O concentration was significantly affected by soil temperature(ST), soil moisture(SM), soil salinity(SS), soil polyphenol oxidase(SPO), soil alkaline phosphatase(SAP), and soil culturable actinomycetes(SCA), ranked as SMSSSTSPOSAPSCA, whereas ST significantly increased soil N_2 O flux, compared with SS. Overall, our study indicated that the soil N_2 O concentration and flux in permafrost zone FTCs were strongly affected by soil properties, especially soil moisture, soil salinity, and soil temperature.  相似文献   

基于FLUS模型与动能定理的城镇用地增长边界划定     

黄康  戴文远  黄万里  欧惠 《地球信息科学学报》2020,22(3):557-567

城镇用地增长边界能够有效控制城市的无序蔓延,对城市健康持续发展具有重要意义。当前针对城镇用地增长边界划定的研究多采用较为成熟的元胞自动机(CA)模型对城市未来格局进行模拟,且研究多集中于单一的城镇用地增长边界划定,尚无对城镇用地增长的惯性边界进行定量划定,而划定惯性边界不仅能够为城市发展预留一定的用地空间,也能提高城市规划的实施效率。对此,本文以2000、2009和2015年福州中心城区土地利用数据为基础,采用FLUS模型进行土地利用模拟,并对模型精度进行了验证(2015年土地利用模拟总体精度达到0.9389,Kappa系数达0.9165),据此预测了2027年的土地利用格局,从中提取城镇用地采取形态学的膨胀与腐蚀法(MED)进行增长边界的划定。在此基础上,本文提出了一种借鉴力学动能定理划定城镇用地增长惯性边界的方法,以坡度和地类作为摩擦力参数,对福州中心城区城镇用地增长惯性边界进行了研究。结果表明,FLUS模型和MED能够有效地对土地利用进行模拟且能较好的对城镇用地增长边界进行拟合;借鉴动能定理的方法能够根据城市不同方向的扩展阻力和各个方向的扩展强度较好地划定其惯性边界,具有现实可操作性和实际参考价值。  相似文献