基于GIS的中国人居环境自然适宜性评价   总被引：13，自引：4，他引：9  

封志明  杨艳昭  张丹  唐焰 《地理学报(英文版)》2009,19(4):437-446

With the degeneration of environment and acceleration of urbanization, human environment has attracted great attention worldwide. This paper sets up the Human Settle-ments Environment Index (HEI) model and evaluates the natural environment suitability for Human Settlements in China based on GIS technology. The results show that the HEI of China decreases from southeast to northwest in general, HEI is significantly correlated with population density at grid size and the correlation coefficient (r) between them reaches 0.93, which indicates that natural environment suitability for Human Settlements has a significant influence on population distribution. Most people in China mainly concentrate in areas with high natural environment suitability. The total suitable area is 430.47×104> km2, which ac-counts for nearly 45% of the total land area in China, while the proportion of people living in the area reaches 96.56%. With a population density of 18 people per square kilometer, the critical area is the transitional region for people to live in China. The critical area covers 225.11×104 km2 with a population of 41.12 million. The non-suitable area covers 304.42×104 km2 with a population of only 2.49 million.  相似文献   

基于模型的3D3C采集设计与评价     

彭苏萍  霍全明  勾精为  程增庆 《煤田地质与勘探》2002,30(5):51-54

对目前三维三分量(3D3C)地震勘探数据采集设计的方法进行了系统分析,利用聚焦射束分析技术(CFP),提出了基于模型的3D3C采集设计方法及其评价的参数。从模型出发的设计方法,能够使3D3C的采集结果更加真实可靠。   相似文献   

郑州冬季黑碳气溶胶浓度变化特征及其与风速风向的关系     

秦亚兰  郑丹  周顺武  等. 《气象与环境科学》2021,44(1):13-20

  相似文献   

湘西保靖白岩洞- 金塘湾洞穴系统的发育特征   总被引：1，自引：0，他引：1  

张顺志  曾志飙  张美良  石明轩  吕中源 《中国岩溶》2000,19(2):188-194

白岩洞- 金塘湾洞穴系统,由主洞和10条支洞组成,呈高、中、低洞穴层相互串通的阶梯状结构,洞道长12km(仅探测6390. 4m)。洞穴系统受下寒武统清虚洞组碳酸盐岩地层分布的控制,洞穴发育对中薄层灰岩和中厚层泥晶灰岩具有优选性,其展布方向受NNE、NE向的破裂构造、揉皱破裂带的控制,表现出较强的方向性。本洞穴系统形成于白垩- 第三纪,至今仍在向纵深发育。洞穴系统演化的空间结构,由早期高层洞、中期中层洞、晚期低层洞依序演变,并由南西向北东逐级演化,在其演化过程中,为垂向、斜向、阶梯式洞道所串通,构成层楼式的网络状洞穴系统。   相似文献   

气候与环境预测和调控中的数学问题   总被引：3，自引：1，他引：2  

曾庆存 《气候与环境研究》2002,7(1):1-6

数学无所不在,现代科学与数学的发展是相互促进的,未能用严谨的数学方式表达的科学问题难于说是属于现代科学范畴的,现代的数学方法与现代提出的科学问题密切地结合是解决问题的关键.作者论述了现代的气候与环境预测和调控中的一些重要的数学问题,其中第一个问题即预测问题,也包括数值天气预测等在内.在这方面论述的问题有预测问题提法的适定性;非线性系统的分叉、混沌、突变等和可预测时效的关系;不完整的观测资料四维同化问题;不同分辨率模式的嵌套问题;和数值求解的算法问题.第二个问题是自然环境的调控或即自然控制论,举例分析了人工影响天气、改良局部气候、泥沙冲淤调控和最优航道工程、以及生态建设规划等问题.    相似文献   

Generalized likelihood uncertainty estimation (GLUE) using adaptive Markov Chain Monte Carlo sampling     

Roberta-Serena Blasone  Jasper A. Vrugt  Henrik Madsen  Dan Rosbjerg  Bruce A. Robinson  George A. Zyvoloski 《Advances in water resources》2008

In the last few decades hydrologists have made tremendous progress in using dynamic simulation models for the analysis and understanding of hydrologic systems. However, predictions with these models are often deterministic and as such they focus on the most probable forecast, without an explicit estimate of the associated uncertainty. This uncertainty arises from incomplete process representation, uncertainty in initial conditions, input, output and parameter error. The generalized likelihood uncertainty estimation (GLUE) framework was one of the first attempts to represent prediction uncertainty within the context of Monte Carlo (MC) analysis coupled with Bayesian estimation and propagation of uncertainty. Because of its flexibility, ease of implementation and its suitability for parallel implementation on distributed computer systems, the GLUE method has been used in a wide variety of applications. However, the MC based sampling strategy of the prior parameter space typically utilized in GLUE is not particularly efficient in finding behavioral simulations. This becomes especially problematic for high-dimensional parameter estimation problems, and in the case of complex simulation models that require significant computational time to run and produce the desired output. In this paper we improve the computational efficiency of GLUE by sampling the prior parameter space using an adaptive Markov Chain Monte Carlo scheme (the Shuffled Complex Evolution Metropolis (SCEM-UA) algorithm). Moreover, we propose an alternative strategy to determine the value of the cutoff threshold based on the appropriate coverage of the resulting uncertainty bounds. We demonstrate the superiority of this revised GLUE method with three different conceptual watershed models of increasing complexity, using both synthetic and real-world streamflow data from two catchments with different hydrologic regimes.  相似文献   

解耦爆炸中震源位置偏离对激发S波的影响     

严波  曾新吾 《地震地磁观测与研究》2008,29(4):33-37

对球形空腔偏心解耦爆炸进行了数值模拟,得到了不同方向和不同爆心距节点的S波和P波速度曲线以及岩石单元中拉伸应力的传播过程。结果表明：空腔偏心解耦爆炸激发的S波具有方向性,S波幅值与对应P波幅值相当,激发S波的物理机制是振荡的拉伸应力,它等效于偶极子震源。  相似文献   

Lowermost mantle shear velocity anisotropy beneath Siberia     

杨凤琴  刘斌  倪四道  曾祥方  戴志阳  吕彦 《地震学报(英文版)》2008,21(2):213-216

Introduction D’’ layer plays an important role in geodynamic process. And seismological research indicates that D’’ layer has large scale seismic anisotropy, however, most research concentrated on areas such as Northern Pacific, Central Pacific, Caribbean, Central America, Alaska etc. (Wookey et al, 2005; Garnero and Lay, 2003; Matzel et al, 1996;  相似文献   

Periodical mixing of MORB magmas near East Pacific Rise 13°N: Evidence from modeling and zoned plagioclase phenocrysts     

GuoLiang Zhang  ZhiGang Zeng  XueBo Yin  DaiGeng Chen  XiaoYuan Wang  XiaoMei Wang 《中国科学D辑(英文版)》2008,51(12):1786-1801

Thirty-six basalt samples from near East Pacific Rise 13°N are analyzed for major and trace elements. Different types of zoned plagioclase phenocrysts in basalts are also backscatter imaged, and major element profiles scanned and analyzed for microprobe. Basalts dredged from a restricted area have evolved to different extents (MgO=9.38wt%—6.76wt%). High MgO basalts are modeled for crystalliza-tion to MgO of about 7wt%, and resulted in the Ni contents (≈28 ppm) that are generally lower than that in observed basalts (>60 ppm). It suggests that low MgO basalts may have experienced more intensive magma mixing. High MgO (9.38wt%) basalt is modeled for self-"mixing-crystallization", and the high Ni contents in low MgO basalts can be generated in small scale and periodical self-mixing of new magma (high MgO). "Mixing-crystallization" processes that low MgO magmas experienced accord with recent 226Ra/230Th disequilibria studies for magma residence time, in which low MgO magmas have experi-enced more circles of "mixing-crystallization" in relatively longer residence time. Magma mixing is not homogeneous in magma chamber, however, low MgO magmas are closer to stable composition pro-duced by periodical "mixing-crystallization", which is also an important reason for magma diversity in East Pacific Rise. Zoned plagioclase phenocrysts can be divided into two types: with and without high An# cores, both of which have multiple reversed An# zones, suggesting periodical mixing of their host magmas. Cores of zoned plagioclase in low MgO (7.45wt%) basalt differ significantly with their mantle in An#, but are similar in An# with microlite cores (products of equilibrium crystallization) in high MgO (9.38wt%) basalt, which further shows that plagioclase phenocryst cores in low MgO basalts may have formed in their parental magmas before entering into the magma chamber.  相似文献   

长江三角洲城市带扩展对区域温度变化的影响   总被引：7，自引：0，他引：7  

杜银  谢志清  曾燕  施雅风  武金岗 《地理学报(英文版)》2007,17(4):387-398

Based on non-radiance-calibrated DMSP/OLS nighttime light imagery from 1992 to 2003, urban land area statistical data, meteorological data and land surface temperature data retrieved by MODIS and NOAA/AVHRR data, the influence of urbanization on regional cli- matic trend of temperature in the Yangtze River Delta (YRD) was analyzed. Conclusions are as follows: 1) There is a significant urbanization process from 1992 to 2003 in the YRD. Four city clusters of Nanjing–Zhenjiang–Yangzhou, Suzhou–Wuxi–Changzhou, Shanghai and Hangzhou Bay form a zigzag city belt. The increase rate of annual mean air temperature in city-belt is 0.28–0.44℃/10a from 1991 to 2005, which is far larger than that of non-city-belt. 2) The urban heat island (UHI) effect on regional mean air temperature in different seasons is summer>autumn>spring>winter. 3) The UHI intensity and the urban total population logarithm are creditably correlated. 4) The UHI effect made the regional annual mean air temperature increased 0.072℃ from 1961 to 2005, of which 0.047℃ from 1991 to 2005, and the annual maximum air temperature increased 0.162℃, of which 0.083℃ from 1991 to 2005. All these indicating that the urban expansion in the YRD from 1991 to 2005 may be regarded as a serious climate signal.  相似文献