基于地统计方法的中国西部气温空间插值研究

利用基于地统计学的简单克里格、普通克里格、协克里格及综合方法4种插值方法对中国西部地区的气温估计结果进行比较研究.气温的空间分布格局和交叉验证结果表明在考虑高程信息后协克里格和综合方法比简单克里格和普通克里格的效果好.相比之下,协克里格比综合方法有更多奇异值出现;其他指标也表明综合方法优于其他3种插值方法.

基于地统计方法的山西省森林木本层生物量及碳密度空间分布格局研究

笔者利用经典统计和地统计分析方法,研究了山西省森林木本层生物量和碳密度的变异性及空间分布格局。结果表明,山西省森林乔木层和灌木层生物量平均值分别为60.26t/hm^2和3.22t/hm^2,木本层的碳密度平均值为31.42t/hm^2.灌木层生物量为强变异,乔木层生物量、木本层地上生物量和碳密度均为中等变异水平。乔木层生物量、灌木层生物量、地上生物量的最优半变异函数模型均为指数模型,碳密度为圆形模型;普通克里格差值的空间预测模型拟合效果较好。

北京市南部平原区地下水位及开采强度时空演变趋势分析

为了解南水北调水入京后对北京市南部平原区地下水位埋深的影响,以北京市大兴区为例,通过收集该区域2010~2020年的地下水位埋深监测数据及用水量数据,采用地统计方法对2010~2020年的地下水位埋深进行了时空变异性分析,并进一步采用主成分分析法评价了该时段的地下水开采强度。结果表明,南水北调入京后,区域地下水位埋深呈减小趋势,2015~2020年相比2010~2014年,地下水位平均埋深由19.13 m减至17.67 m,说明南水北调入京后,对区域地下水位的恢复具有明显的正向效应;基于地统计半变异函数模型计算南水北调入京前后地下水位埋深的块金效应值,发现2015~2020年与2010~2014年相比,地下水位埋深的块金效应值由55.92%减至39.05%,说明人为因素对地下水位埋深的影响处于减弱的状态;基于主成分分析法计算了2010~2020年对地下水开采强度的影响变化,表明区域用水对地下水开采强度的影响总体呈减小趋势,其中工业用水量、第三产业用水量及农业用水量对地下水开采强度的影响处于减小趋势,生活用水量对地下水开采强度的影响处于增大趋势。研究结果可为南水北调沿线区域的地下水资源管理提供理论和方法借鉴。

黄河流域(陕西段)景观生态风险评价及预测分析

[目的]以可持续发展为准则,分析黄河流域的景观生态风险时空演变特征,为黄河流域的高质量发展提供科学依据。[方法]基于1990-2020年土地利用数据计算景观生态风险指数。进行空间自相关分析,在空间上探索景观生态风险指数与驱动因素的空间相关性。并设定自然发展、耕地保护、生态保护和可持续发展四个情景,采用Markov-Flus模型对未来景观生态风险指数进行预测。[结果]研究区内,榆林市、渭南市以及咸阳市北部的景观风险较高,近年来高风险区、较高风险区逐渐收缩;整体的分布呈现“南冷北热”的特点。[结论]不同区域的景观生态风险收缩或扩张情况不同,应以可持续发展为准则,在不同地区采取不同的保护措施。

基于BP神经网络与GIS的巢湖水华危险性评价

选择溶解氧、化学需氧量、总磷、总氮、叶绿素浓度作为评价指标，建立了巢湖水华危险性评价分级标准。采用BP神经网络模型对指标进行了评价，得出巢湖12个水质监测站点的水华危险性等级，并借助GIS的空间信息展布功能，获得了巢湖2000-2007年的水华危险性区域分布及年际变化。结果表明，巢湖西部湖区的水华危险性程度最高，暴发水华的可能性最大，中部湖区的水华危险性程度较高，东部湖区的水华危险性程度一般；BP神经网络模型与GIS相结合的方法直观、简便，具有推广应用价值。

牧草氮素产量的时空变异研究

以英国Hillsborough农业研究所附近的一块7 9hm2的牧草田为研究区,采用地统计方法研究分析连续3年的牧草氮素产量在3个收割季节的空间变异,并研究了第一、二季其空间分布的变异在时间上的稳定性。结果表明,试验区牧草氮素产量在单个田块间存在较大的空间变异,而且这种变异在不同的生长季呈现有规律变化,变量施肥是必要的;牧草氮素产量的空间分布与地形有很大的关系,可以根据地形将试验区分片管理。

海沟河小流域耕地土壤重金属污染与生态风险评价

为了解海沟河小流域耕地重金属污染现状,采集海沟河小流域耕地表层土壤样品,采用反距离权重插值方法,结合遥感影像解译和Arc GIS地统计方法,分析海沟河小流域耕地重金属Cd、Pb、Hg、Cu、As浓度分布。结果表明:Cd、Pb、Hg、Cu、As平均浓度分别为0.307、23.422、0.041、21.544和12.235 mg/kg,均高于黑龙江省土壤背景值;Cd浓度超过GB 15618—1995《土壤环境质量标准》二级标准,其余重金属浓度均满足一级标准。重金属空间分布为As浓度自东向西逐渐减小;Cd浓度与As相反,为自东向西逐渐增大。采用潜在生态风险指数法对耕地重金属潜在生态风险进行评价,结果表明,Cd、Hg的潜在生态风险等级分别为高度和中等,Pb、Cu和As为轻度,海沟河小流域耕地潜在生态风险为中等。

某重金属污染场地典型物质浓度空间分布研究

以上海某重金属污染场地为例,运用地统计方法探索了研究区内三种典型物质(Cu、Sb和Ni)的空间变异特征、分布特征和相关关系。结果表明,受人为作用下的随机因素影响,三种重金属浓度分布的空间变异性较强,占场地面积80%范围内的三种重金属浓度超过背景值,占场地面积21.37%和23.33%的Sb和Ni超过上海市敏感用地筛选值,且表层污染范围大于深层,主要分布于原冶炼车间和机械加工车间。此外Sb和Ni分别与Cu表现出显著的共生关系。

山东烟台南部海岸带地区土壤重金属来源、空间分布及潜在风险评价

海岸带处于陆地和海洋的接合部,人类开发活动密集,环境影响因素日趋复杂。选取烟台南部海岸带为研究对象,系统采集686个表层土壤样品对As,Cd,Cr,Cu,Hg,Ni,Pb,Zn共8个重金属元素含量进行测量,采用多元统计法及地统计法分析了8个重金属元素的来源及分布特征。最后对烟台南部海岸带地区进行了潜在生态风险评价。研究结果表明烟台南部海岸带地区整体污染程度较轻,所有重金属元素含量平均值均未超过国家二级标准。其中Cr,Ni,Cu元素主要来源于成土母质;As,Pb为混合源;Cd,Zn主要来自于工业三废、农业生产。研究区整体处于中低生态风险水平,Cd,Hg元素高生态风险点数量较多,需优先治理。

Spatial Variability of Soil Organic Carbon in a Watershed on the Loess Plateau

Soil organic carbon (SOC) has great impacts on global warming, land degradation and food security. Classic statistical and geostatistical methods were used to characterize and compare the spatial heterogeneity of SOC and related factors, such as topography, soil type and land use, in the Liudaogou watershed on the Loess Plateau of North China. SOC concentrations followed a log-normal distribution with an arithmetic and geometric means of 23.4 and 21.3 g kg-1, respectively, were moderately variable (CV = 75.9%), and demonstrated a moderate spatial dependence according to the nugget ratio (34.7%). The experimental variogram of SOC was best-fitted by a spherical model, after the spatial outliers had been detected and subsequently eliminated. Lower SOC concentrations were associated with higher elevations. Warp soils and farmland had the highest SOC concentrations, while aeolian sand soil and shrublands had the lowest SOC values. The geostatistical characteristics of SOC for the different soil and land use types were different. These patterns were closely related to the spatial structure of topography, and soil and land use types.

Modified Method for Estimating Organic Carbon Density in Discontinuous Karst Soil Using Ground-Penetrating Radar and Geostatistics

The conventional method which assumes the soil distribution is continuous was unsuitable for estimating soil organic carbon density(SOCD) in Karst areas because of its discontinuous soil distribution. The accurate estimation of SOCD in Karst areas is essential for carbon sequestration assessment in China. In this study, a modified method,which considers the vertical proportion of soil area in the profile when calculating the SOCD, was developed to estimate the SOCD in a typical Karst peak-cluster depression area in southwest China. In the modified method, ground-penetrating radar(GPR) technology was used to detect the distribution and thickness of soil. The accuracy of the method was confirmed through comparison with the data obtained using a validation method, in which the soil thickness was measured by excavation. In comparison with the conventional method and average-soil-depth method,the SOCD estimated using the GPR method showed the minimum relative error with respect to that obtained using the validation method. At a regional scale, the average SOCDs at depths of 0-20 cm and 0-100 cm, which were interpolated by ordinary kriging,were 1.49(ranging from 0.03-5.65) and 2.26(0.09-11.60) kgm-2based on GPR method in our study area(covering 393.6 hm2), respectively. Therefore, the modified method can be applied on the accurate estimation of SOCD in discontinuous soil areas such as Karst regions.

Rocky Desertification Risk Zone Delineation in Karst Plateau Area:A Case Study in Puding County,Guizhou Province

Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area （about 50.81%） was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.

Spatial Variability of Soil Organic Carbon in Different Hillslope Positions in Toshan Area, Golestan Province, Iran: Geostatistical Approaches

Accessibility to organic carbon(OC) budget is required for sustainable agricultural development and ecosystem preservation and restoration. Using geostatistical models to describe and demonstrate the spatial variability of soil organic carbon(SOC) will lead to a greater understanding of this dynamics. The aim of this paper is to present the relationships between the spatial variability of SOC and the topographic features by using geostatistical methods on a loess mountain-slope in Toshan region, Golestan Province, northern Iran. Hence, 234 soil samples were collected in a regular grid that covered different parts of the slope. The results showed that such factors as silt, clay, saturated moisture content, mean weighted diameter(MWD) and bulk density were all correlated to the OC content in different slope positions, and the spatial variability of SOC more to slope positions and elevations. The coefficient of variation(CV) indicated that the variability of SOC was moderate in different slope positions and for the mountain-slope as a whole. However, the higher variability of SOC(CV = 45.6%) was shown in the back-slope positions. Also, the ordinary cokriging method for clay as covariant gave better results in evaluating SOC for the whole slope with the RMSE value 0.2552 in comparison with the kriging and the inverse distance weighted(IDW) methods. The interpolation map of OC for the slope under investigation showed lowering SOC concentrations versus increasing elevation and slope gradient. The spatial correlation ratio was different between various slope positions and related to the topographic texture.

3D inversion of borehole gravity data using cokriging

Borehole gravity has been used in mineral exploration recently with the advent of slim-hole gravimeters. It is logical to perform inversion to utilize the information in the newly acquired data. The inversions were carried out by using cokriging,which is a geostatistical method of estimation that minimizes the error variance by applying cross-correlation between several variables. In this study the estimated densities are derived by using boreholes gravity and known densities along the borehole. This method does not need iterative process and computes efficiently. The selection of examples demonstrates that this method has the ability to include physical property from borehole measurements in the inversion. The synthetic examples demonstrate the density variation along a borehole can be well determined without depth constraints in the inversion. The resolution of the recovered model can be further improved by including the densities along the borehole for inversion. However,this capability decreases dramatically with the increasing of distance between the anomalous body and the borehole.

Study on the Calibration Function of Local Earthquake Magnitude in the Gansu Region

To calculate the deviations between single station magnitudes and average ones by the magnitude residual statistical method,the paper selects 13086 seismic events recorded by the Gansu broadband digital seismic network from January 2009 to December 2012. The frequency distribution and quantitative statistics of the deviations of earthquake magnitude are analyzed. The MLcalibration function is modified and a uniform local magnitude system characteristic of the Gansu region,is obtained.

Analyzing Land-use Change in Farming-pastoral Transitional Region Using Autologistic Model and Household Survey Approach

Land change science （LCS） strives to understand and model land-use change, which will further advance the understanding of multiple issues in the socio-ecological systems. Based on GIS/RS techniques, autologistic model, and household survey method, this study investigated major land use changes and their causes from 1978 to 2008 in Uxin Banner （county-level）, Inner Mongolia in China and then developed an understanding of the relationships between household livelihood and land-use pattern. Results showed that cultivated land increased from 1988 to 2000, and leveled offafter 2000. Built-up land increased stably for the period 1978 2008. The change of grassland and bare land differed among the three periods. From 1978 to 1988, grassland increased by 23.3%, and bare land decreased by 20.48%. From 1988 to 2000, bare land expanded by 1.7%, but grassland declined by 1.3%. From 2000 to 2008, an increase in grassland area by 1.8% was observed, but a decrease in bare land area by 9.0% was witnessed. The autologistic models performed better than logistic models as indicated by lower Akaike Information Criterion （AIC） values. Factors associated with human activities significantly correlated with the change of cultivated land, forest land, grassland, and built-up land. The produce prices and extensive cultivated land use are major issues in the farming area. This study suggests that completing land circulation systems and maintaining the stability of price are effective solutions. By contrast, reclamation and overgrazing are major concerns in the pastoral areas. Implementing environmental policies effectively, transferring population out of rural pastoral areas, and developing modem animal husbandry are effective ways to address these issues.

International Accounting Standards Board （IASB） and Financial Accounting Standards Board （FASB） Convergence Project： Where Are They Now？

The convergence project between the International Accounting Standards Board （IASB） and the Financial Accounting Standards Board （FASB） in the United States （US） was signed on September 18, 2002 in Norwalk, Connecticut in the US. The first is responsible for issuing International Financial Reporting Standards （IFRS） nowadays, which were created 40 years ago. More than one century ago, local regulations are used in the US. The boards differ in years of experience. With the signing of the agreement, both institutions are working to reduce the divergence of accounting. Although they have made a significant progress, it is appropriate to examine whether the difference in approaches to accounting will affect the achieved agreements. It is relevant to investigate whether the years leading the standards adopted in different countries will impact the final result. The date of completion of the project has been postponed and still has not indicated the date of termination. This research is an analysis of the importance of the convergence of accounting standards at a global level. The study presents statistics on the status of the adoption of international standards by country. The study shows a summary of the expressions made by the directors of both boards about the future of the project.

A simple method to extract glacier length based on Digital Elevation Model and glacier boundaries for simple basin type glacier

Glacier length is a key morphological element that has many glaciological applications; however, it is often difficult to determine, especially for glaciers that cover larger spatial areas or those that exhibit frequent temporal change. In this paper, we describe a new Arc GIS-based method that can derive glacier flow lines for determining glacier length based on digital elevation model and glacier outlines. This method involves(1) extraction of the highest and lowest points on a glacier,(2) calculation of 10-m contour lines on the glacier from 10 m to 100 m height, and(3) connection of the midpoints of each contour line with the highest and the lowest points in order to create a flow line, which is subsequently smoothed. In order to assess the reliability of this method, we tested the algorithm's results against flow lines calculated using field measurements, analysing data from the Chinese Glacier Inventory, and manual interpretation. These data showed that the new automated method is effective in deriving glacier flow lines when contour lines are relatively large; in particular, when they are between 70 m and 100 m. Nonetheless, a key limitation of the algorithm is the requirement to automatically delete repeated and closed curves in the pre-treatment processes. In addition to calculating glacier flow lines for derivation of glacier length, this method also can be used to effectively determine glacier terminus change.

Increase of Local Seismicity Due to the Construction of Taipei 101?

Considering the controversy over whether the Taipei 101 skyscraper has induced an increase of local seismicity, we reanalyzed the local earthquake catalogue before and after the construction to investigate whether the reported seismicity increase related to the construction is statistically significant. Statistical tests obtained a positive conclusion about the apparent seismicity increase. However, the calculation of maximum ACFS shows that at most a 2.2 × 10^-4 bar Coulomb Failure Stress change was produced by the construction. Therefore, whether the construction of Taipei 101 really triggered the increase of seismicity still remains an open question： Statistically-yes; physically-no.

Landslide Hazard Mapping During a Large Scale Earthquake

This paper reports a method to make hazard maps of sediment disasters resulting from an earthquake and following heavy rainfall for the entire region of Gunma prefecture, Japan. Firstly, we identified the slopes in the study area, which are susceptible to large-scale landslides and land failures during an earthquake with a magnitude of seven on the Richter scale. To analyze the sheer volume of the data, we employed a statistical method to evaluate the susceptibility, mainly considering geomorphologic conditions. Secondly, we extracted mudflow and slope failure susceptible areas and potential flooding zones resulting from a damming at a river triggered by the earthquake and heavy rainfall, and we identified the settlements which would be isolated by the road disruption caused by the sediment disasters. As the result, 359 settlements were classified as potential isolation areas. Combining the above-mentioned susceptibility maps, we obtained two types of sediment disaster hazard maps of the study area, depicting the potential hazards which would occur during the earthquake and the disasters which would be caused by heavy rainfall following the quake, respectively. These hazard maps and the disaster information would be useful for the regional disaster prevention planning and countermeasures in the future.