Dynamic Identification and Evolution of Urban-suburban-rural Transition Zones Based on the Blender of Natural and Humanistic Factors: A Case Study of Chengdu, China

Urban-suburban-rural(U-S-R)zones exhibit distinctive transitional characteristics in interaction between human and nature.U-S-R transition zones(U-S-RTZ)are also highlighting the function diversity and landscape heterogeneity across territorial spaces.As a super megacity in western China,Chengdu’s rapid urbanization has driven the evolution of U-S-R spaces,resulting in a sequential structure.To promote the high-quality spatial development of urban-rural region in a structured and efficient manner,it is essential to con-duct a scientific examination of the multidimensional interconnection within the U-S-RTZ framework.By proposing a novel identifica-tion method of U-S-RTZ and taking Chengdu,China as a case study,grounded in a blender of natural and humanistic factors,this study quantitatively delineated and explored the spatial evolutions of U-S-RTZ and stated the optimization orientation and sustainable devel-opment strategies of the production-living-ecological spaces along the U-S-R gradients.The results show that:1)it is suitable for the quantitative analysis of U-S-RTZ by established three-dimensional identification system in this study.2)In 1990-2020,the urban-sub-urban transition zones(U-STZ)in Chengdu have continuously undergone a substantial increase,and the scale of the suburban-rural transition zones(S-RTZ)has continued to expand slightly,while the space of rural-ecological transition zones(R-ETZ)has noticeably compressed.3)The landuse dynamics within U-S-RTZ has gradually increased in 1990-2020.The main direction of landuse transition was from farmland to construction land or woodlands,with the expansion of construction land being the most significant.4)R-ETZ primarily focus on ecological functions,and there is a trade-off relationship between the production-ecological function within the S-RTZ,and in the U-STZ,production-living composite functions are prioritized.This study emphasizes the importance of elastic planning and precise governance within the U-S-RTZ in a rapid urbanization region,particularly highlighting the role of suburbs as landscape corridors and service hubs in urban-rural integration.It elucidates to the practical implications for achieving high-quality development of integrated U-S-R territorial spaces.

Spatial Pattern and Development of Protected Areas in the North-south Transitional Zone of China

The north-south transitional zone in China mainly consists of the Qinling-Daba Mountains. It is the most important West-East geo-ecological space in China, containing protected areas vital for biodiversity conservation and ecological security of China. The protection and rational development of its natural habitat is of great significance to China’s ecological security and integration of protected areas based on mountain forest ecosystems on a global scale. In this study, five important types of protected areas in the transitional zone were selected, and their spatial patterns were analysed. Spatial analysis methods, such as kernel density estimation and accessibility analysis, were employed for both point and areal data, and focused on four aspects: land use scale, shift in the centre of gravity, spatial agglomeration, and accessibility. In addition, policy background and evolution of spatial and temporal characteristics of the protected area system in the transitional zone from 1963 to 2017 were also examined. We analysed the characteristics and geographical significance of the West-east corridor using the spatial pattern of the protected area system from the perspective of ecological and economic spaces. We focused on spatial shape, type intersection, and key areas to analyse the spatial overlap of the protected areas. Protected area establishment was divided into three stages: initial(1956–1980), rapid development(1981–2013), and national park transformation(2014–present). These stages reflected the change in the concept of ‘simple protection—sustainable use—integration and upgrade’ for protected areas of China. The spatial centre of gravity of the protection zone system was located in the west Qinling-Daba Mountains, and its high-density core exhibited a relatively stable N-shaped structure composed of four gathering areas. Affected by factors such as geographic environment and socio-economic development density, the average access time for protected areas was high(1.56 h);wetland parks and scenic areas are located closer to the city centre. As the West-east corridor in the transitional zone extends from west to east, there is a clear spatial dislocation between the development of protected areas and the intensity of human activities. During development, differentiated goal orientation should be adopted based on the idea of zoning and classified governance. With the advancement of the construction of protected areas, the spatial overlap of protected areas in the transition zone has become more prominent. At present, the spatially overlapped protected areas in the transitional zone remain prominent, with inclusion overlap being the most common, and forest parks exhibiting the highest probability of overlap with other protected areas, we should focus on in the integration process of the corridor-type ecological space based on the mountain forest ecosystem.

Spatial pattern of plant species diversity and the influencing factors in a Gobi Desert within the Heihe River Basin, Northwest China

Understanding the spatial pattern of plant species diversity and the influencing factors has important implications for the conservation and management of ecosystem biodiversity. The transitional zone between biomes in desert ecosystems, however, has received little attention in that regard. In this study, we conducted a quantitative field survey （including 187 sampling plots） in a 40-km2 study area to determine the spatial pattern of plant species diversity and analyze the influencing factors in a Gobi Desert within the Heihe River Basin, Northwest China. A total of 42 plant species belonging to 16 families and 39 genera were recorded. Shrub and semi-shrub species generally represented the major part of the plant communities （covering 90% of the land surface）, while annual and perennial herbaceous species occupied a large proportion of the total recorded species （71%）. Patrick richness index （R）, Shannon-Wiener diversity index （H）, Simpson＇s dominance index （D）, and Pielou＇s evenness index （I） were all moderately spadaUy variable, and the variability increased with increasing sampling area. The semivariograms for R and H＇ were best fitted with Gaussian models while the semivariograms for D andJ were best fitted with exponential models. Nugget-to-still ratios indicated a moderate spatial autocorrelation for R, H＇, and D while a strong spatial autocorrelation was observed for J. The spatial patterns of R and H＇ were closely related to the geographic location within the study area, with lower values near the oasis and higher values near the mountains. However, there was an opposite trend for D. R, H＇, and D were significantly correlated with elevation, soil texture, bulk density, saturated hydraulic conductivity, and total porosity （P〈0.05）. Generally speaking, locations at higher elevations tended to have higher species richness and diversity and the higher elevations were characterized by higher values in sand and gravel contents, bulk density, and saturated hydraulic conductivity and also by lower values in total porosity. Furthermore, spatial variability of plant species diversity was dependent on the sampling area.

Spatial structure and seasonal changes of nekton assemblages in the Taiwan Strait

The Taiwan Strait is a transition zone between the East China Sea and the South China Sea with unique hydrology and a geographical environment that creates special marine community features.To analyze the spatial structure and seasonal changes of the nekton assemblages in the Taiwan Strait,seasonal experimental trawl surveys were conducted during 2006-2007.The results showed that there were two assemblages in the area with different sets of species,and the average similarity within each group varies between 39.38% and 74.20%.By using multivariate statistical analysis and analyzing the distribution of dominant species,we found that the structures of the assemblages had obvious seasonal variation.The middle region from the Putian transect to the Xiamen transect could be considered a mixing area for the two assemblages.The analysis of the relationship between species assemblages and environmental factors indicated that temperature was the most important factor affecting the community structure in cold seasons,and 22.5°C and 17°C could be considered dividing lines for spring and winter,respectively.In warm seasons,the most important factor was water depth,but the relationship with depth was not as significant,with a correlation between 0.264 and 0.399.The seasonal changes of nekton assemblages basically reflected the dynamic currents in the Taiwan Strait.The south coastal assemblage extended to nearly the entire area of the Taiwan Strait along with a strong and intense warm current that shrinks in spring and winter when the southward intrusion of the cold Zhejiang-Fujian coastal current becomes stronger.The impact of shortterm and long-term environmental changes,such as extreme weather,global warming and human activity on nekton assemblages,had been recognized but need further research.Our study on nekton assemblages could be used as a baseline for measuring future changes.

Spatial identification and scenario simulation of the ecological transition zones under the climate change in China

Explicitly identifying the spatial distribution of ecological transition zones(ETZs)and simulating their response to climate scenarios is of significance in understanding the response and feedback of ecosystems to global climate change.In this study,a quantitative spatial identification method was developed to assess ETZ distribution in terms of the improved Holdridge life zone(iHLZ)model.Based on climate observations collected from 782 weather stations in China in the T0(1981–2010)period,and the Intergovernmental Panel on Climate Change Coupled Model Intercomparison Project(IPCC CMIP5)RCP2.6,RCP4.5,and RCP8.5 climate scenario data in the T1(2011–2040),T2(2041–2070),and T3(2071–2100)periods,the spatial distribution of ETZs and their response to climate scenarios in China were simulated in the four periods of T0,T1,T2,and T3.Additionally,a spatial shift of mean center model was developed to quantitatively calculate the shift direction and distance of each ETZ type during the periods from T0 to T3.The simulated results revealed 41 ETZ types in China,accounting for 18%of the whole land area.Cold temperate grassland/humid forest and warm temperate arid forest(564,238.5 km~2),cold temperate humid forest and warm temperate arid/humid forest(566,549.75 km~2),and north humid/humid forest and cold temperate humid forest(525,750.25 km~2)were the main ETZ types,accounting for 35%of the total ETZ area in China.Between 2010 and 2100,the area of cold temperate desert shrub and warm temperate desert shrub/thorn steppe ETZs were projected to increase at a rate of 4%per decade,which represented an increase of 3604.2,10063.1,and 17,242 km~2 per decade under the RCP2.6,RCP4.5,and RCP8.5 scenarios,respectively.The cold ETZ was projected to transform to the warm humid ETZ in the future.The average shift distance of the mean center in the north wet forest and cold temperate desert shrub/thorn grassland ETZs was generally larger than that of other ETZs,with the mean center moving to the northeast and the shift distance being more than 150 km during the periods from T0 to T3.In addition,with a gradual increase of temperature and precipitation,the ETZs in northern China displayed a shifting northward trend,while the area of ETZs in southern China decreased gradually,and their mean center moved to high-altitude areas.The effects of climate change on ETZs presented an increasing trend in China,especially in the Qinghai-Tibet Plateau.

荒漠-绿洲过渡带NDVI演变及影响因子相关性分析

荒漠-绿洲过渡带是绿洲与荒漠相互转化过程中表现最活跃的地区,具有防止荒漠扩张、维持绿洲生态安全等重要的生态功能。本研究以民勤县为研究区域,根据绿洲外围归一化差异植被指数(Normalized difference vegetation index,NDVI)的变化规律,确定民勤荒漠-绿洲过渡带的范围;利用2000—2020年内最大NDVI数据及降水、温度、日照时数、土壤水分影响因子,在像元尺度采用偏相关及多元相关分析方法,研究过渡带NDVI变化趋势及影响因子相关性分析。结果表明,绿洲边界外5000 m范围为民勤荒漠-绿洲过渡带范围,其中绿洲外0~300 m为过渡带核心区,300~2000 m为过渡带交错区,2000~5000 m范围为过渡带缓冲区。自2000年以来,过渡带区域NDVI整体呈增加趋势,其中,明显改善和稳定不变的面积占比较高,分别为47.8%和42.2%,其他占比较小,严重退化区域主要在靠近绿洲的过渡带核心区。降水增加对过渡带南部地带性植被的改善起主导作用,温度的上升对过渡带东部及西北部NDVI改善的促进作用更明显,日照时数的增加对过渡带西部及东南部NDVI改善的促进作用更大,土壤水分的增加对过渡带整体NDVI的改善均具有促进作用。土壤水分和降水是促进过渡带NDVI改善的主要因子。

Land use transition and rural spatial governance: Mechanism, framework and perspectives

The pattern for utilization of rural space is closely related to rural transformationdevelopment (RTD). The problem of rural space utilization is an important manifestation of theuncoordinated relationship between land use patterns and rural development status during atransformation period. Considering the rural space utilization issue, this article seeks to analyzethe interaction mechanisms between land use transition (LUT) and rural spatial governanceand then build a rural spatial governance analysis framework based on LUT. Also, thepaper explores the internal relationship between rural spatial governance and rural vitalizationand discusses the research prospective of the interaction. The study found that: (1) Ruralspace utilization has systemic problems such as limited development space, ill-defined ownershipand poor organization, which have become important obstacles for rural development.(2) The uncoordinated relationship between LUT and RTD is an important reason for the dilemmasurrounding rural space utilization. (3) The LUT provides a basis for determining thetiming of rural spatial governance, specifying spatial governance objectives, and clarifyingrural spatial governance methods. (4) The construction of a comprehensive analysis frameworkof “matter-ownership-organization” of rural space based on the LUT has created conditionsfor the orderly promotion of rural spatial governance. (5) Rural spatial governance whichfacilitates the integration of urban-rural development is an important foundation for rural vitalization.(6) Interaction analysis of LUT, RTD and rural spatial governance is conducive tofacilitating research on the operational mechanism of rural regional systems and to expandingthe research field of rural geography.

长江经济带臭氧污染全域空间动态跃迁与局部空间驱动差异

作为臭氧污染治理的重点区域,提升对长江经济带臭氧污染的时空变化认知和探寻污染产生的主要驱动因素成为实现协同治理的两大基础性关键问题。基于2015—2020年长江经济带各地市的臭氧浓度监测数据,运用探索性时空数据分析(ESTDA)研究长江经济带全域空间臭氧污染的特征与时空变化过程,应用面板分位数回归模型分析长江经济带臭氧污染格局变化背后的主要驱动因素,并进一步探究其局部空间的驱动差异,进而提升对长江经济带臭氧污染的科学认知。研究发现,长江经济带臭氧污染格局整体呈现东高西低态势,重污染区域由下游向中上游扩展;臭氧污染的空间相关性逐年增强,且呈现集聚与分异并存的空间演进特征;臭氧浓度的时空跃迁具有较强的空间依赖性,但整体呈现一定的转移惰性;地市空间尺度的臭氧浓度时空跃迁驱动类型存在差异。上海、长沙等中下游城市表现为开放-城镇化驱动型;贵阳、昆明等上游城市表现为科技-绿化制约型。从上游至下游臭氧浓度的时空跃迁呈现出“同向制约—逆向发展—同向发展”的递变格局。

黑河流域荒漠绿洲过渡带两种优势植物种群空间格局特征

应用地统计学的原理和方法 ,对降水量 1 1 7 1mm、降水量和潜在蒸发量比值为 0 0 5的荒漠绿洲过渡带斑块状植被优势植物泡泡刺、红砂种群的密度、盖度以及泡泡刺沙堆体积和高度的空间格局进行了研究 .结果表明 ,泡泡刺和红砂种群平均盖度分别为 1 5 6± 2 34%和 0 2 3± 0 2 2 % ;密度分别为 1 5± 1 8丛·1 0 0m-2 和 2 3± 2 1株·1 0 0m-2 泡泡刺灌丛沙堆是稳定戈壁下垫面受风沙流干扰形成的一种景观 ,灌丛高度和体积都比较小 ,平均值分别为 0 1 8± 0 1 5m和 0 1 0± 0 1 8m3 泡泡刺种群在样地内靠近绿洲和浅山区有几条明显的分布带 ,而红砂分布相对均匀 .用半方差函数分析表明 ,两种种群密度和盖度的块金值与基台值之比都比较小 ,介于 0 0 8～ 0 1 2之间 ,说明在总空间异质性中随机因素所起的作用很小 ,占 8%～ 1 2 % .两种种群盖度和密度的变程相近 ,基本在 34m以内 ,其中随机因素引起的异质性对应的尺度在 1 0m以下 ,而结构性因素引起的异质性对应的尺度为 1 0～ 34m .泡泡刺和红砂种群盖度和密度的空间异质性均具有各向同性和各向异性特征 ,其中红砂种群的各向同性的范围略大于泡泡刺种群 .

转型期开发区发展与城市空间重构——以北京市为例

1992年以来中国经济的转型与发展促进了城市的空间重构,开发区在其中起着非常重要的作用,是这一时期我国城市空间重构的主要动力和重要内容。文章以北京为例,首先简要介绍了我国的转型与发展、开发区发展和城市的空间重构,然后重点论述了开发区的发展对城市空间重构的影响,并据此提出了4点原则性措施以促进中国城市与开发区空间的整合发展。

毛乌素沙漠-黄土高原过渡带土壤养分空间异质性

毛乌素沙漠-黄土高原过渡带土壤养分的空间异质性和生态学过程,对沙荒地整治的机理研究具有重要的意义。以毛乌素沙漠-黄土过渡带为研究区,结合布点取样和室内分析,运用经典统计学和地统计学方法对其全氮、有效磷、速效钾含量的空间异质性进行分析。结果表明,(1)土壤全氮、有效磷、速效钾的平均含量分别为0.39 g/kg、9.65 mg/kg和106.84 mg/kg。3种养分的变异系数为40.54%—84.62%,均属于中等程度变异,其中全氮变异系数最大,速效钾变异系数最小。(2)半方差分析结果显示,3种养分空间变异性的最佳拟合模型均为高斯模型,空间自相关性均随着滞后距离的增加而呈下降趋势。3种养分空间变异性的块金值/基台值比值在0.09%—32.82%,全氮、有效磷具有强烈的空间相关性,结构性因素对变异起主导作用;速效钾具有中等强度的空间相关性,结构性因素和随机性因素共同对变异起主导作用。(3)克里金插值图显示3种养分含量均表现为随着地势的降低而逐渐升高的趋势,全氮含量整体呈斑点状分布,插值图较破碎,有效磷和速效钾含量整体呈条带状分布,连续性较好。(4)毛乌素沙漠-黄土过渡带土壤养分的空间变异性与地形、地貌、植物分布以及非自然因素都有关,但是以地形因素的影响为主。开展沙漠-黄土过渡带土壤养分空间异质性特征研究,为开展沙荒地整治工程,生态系统修复提供了理论依据。

荒漠绿洲过渡带植被空间异质性的可塑性面积单元问题

以荒漠绿洲过渡带植被为研究对象 ,采用地统计理论与方法 ,以优势植物泡泡刺 (Nitrariasphaerocarpa)和红砂 (Reaumuriasoongorica)种群为例 ,采用一个样地内 2 5 0 0个 10m× 10m小样方中获取的植物盖度数据来研究采样尺度和划区方式对荒漠植被空间异质性的影响。其中尺度效应研究的思路是 :一是保持粒度 (样方 )不变 ,增加幅度 (样地 )分析其对空间异质性的影响 ;二是保持幅度不变 ,改变粒度进行分析。划区效应是在样地尺度 (5 0 0m×5 0 0m)上 ,把整块样地数据聚合成 10m× 2 0 0m、2 0m× 10 0m、4 0m× 5 0m、5 0m× 4 0m、10 0m× 2 0m和 2 0 0m× 10m等不同形状和不同方向的网格进行地统计分析。结果表明 :荒漠绿洲过渡带植被空间异质性受采样尺度和划区方式影响显著。当样地面积小于 2 0 0m× 2 0 0m时 ,所获取的数据不能真实反映泡泡刺种群的空间异质性 ;当样地面积小于 10 0m× 10 0m时 ,所获取的数据不能真实反映红砂种群的空间异质性。调查泡泡刺和红砂种群的空间格局时 ,样方面积在 2 0m× 2 0m到 30m× 30m较为合适。植被空间异质性参数对划区方式的敏感性较强 ,其中泡泡刺种群的敏感性高于红砂种群。

农牧交错带本氏针茅坡地土壤-植物系统磷素分布特征

明确农牧交错带草坡地土壤-植物系统磷素分布特征对于草坡地生态系统磷素管理、空间分布和磷素流失预测具有重要科学意义。本研究针对黄土高原农牧交错带本氏针茅坡地,分析了草坡地土壤-植物系统磷素沿坡面的分布特征,并且从不同空间尺度研究了土壤-植物系统磷素的空间结构特征,以揭示农牧交错带草坡地土壤-植物系统磷素分布规律。结果表明,随坡位的降低,草坡地植物生物量、植物磷素含量和储量均逐渐增加,土壤全磷和速效磷含量在坡上部和坡中部相近,且均低于坡底部;这些变量的变异系数均以坡底部最小。植物磷素含量和土壤全磷的变异系数由坡顶向下依次为34.25%、25.98%、10.02%和24.05%、15.27%、10.85%,表明坡底部土壤-植物系统磷素分布相对均匀。各变量的最佳拟合模型在3个分析尺度上均保持一致,植物生物量和土壤速效磷的最佳拟合模型为指数模型,土壤全磷以球状模型拟合效果最佳,而植物磷素以高斯模型拟合效果最好。随分析尺度的增加,块金常数、块金效应逐渐增大。植物磷素含量在5、10、15 m 3个尺度上的块金常数和块金效应依次为0.010、0.010、0.011和7.9、8.5、8.9,即样点间的空间依赖性逐渐减弱,空间相关性减弱。这表明农牧交错带草坡地土壤-植物系统磷素在不同尺度上空间结构比较稳定,属中等或强空间相关性,其空间变异主要来源于结构性因素。

过渡带城市空间扩展特征及影响因素分析——以张家口市为例

由于过渡带地区城市空间扩展在不同历史时期主导因素不同,以处在农牧交错带的张家口为例,利用遥感影像数据和历史资料,使用地理信息系统空间分析方法,探讨了张家口城市发展演变历程,确定了城市空间扩展特征,并提出影响城市空间扩张的主导因素.研究表明：张家口城市增长极经历了由上堡-下堡-火车北站-火车南站的迁移过程;城市面积从1975年到2013年扩大了5倍,其中尤以2004年以来扩张速率最快;空间扩展的方向以南为主;城市空间集中在700～800 m高程带上,并由早期的向城区周围的高地发展转向为2004年以来的向城南的洋河谷地蔓延.过渡带两侧所固有的区域差异产生了不同的利用空间获取利益的方式,是城市空间扩展的根本动力.在边疆不稳定时期,过渡带特殊的地形条件符合域内首位城市军事防御的需要,催生了城的落地;异样的气候条件造成了不同的生产生活方式,在农耕区和游牧区产生了商品交换的需求,催化了市区的发展;交通方式的改善加速了生产要素的集聚与扩散,加快了城市的生长;而政策的融通与否成为人口集散的的政治基础,影响着城市的兴衰.今后,过渡带城市对于生态要素有效流通的媒介作用将更为凸显,成为影响城市空间扩展的关键要素.

关中-天水经济区生态系统服务价值转移研究

基于遥感和地理信息系统相关方法,对关中-天水经济区近10年来生态服务价值在时间和空间上的价值转移进行研究.结果显示:(1)2000年、2005年和2010年的生态服务价值分别为178.53、263.13和270.65亿元;(2)2000—2010年宝鸡市和商洛市的生态服务价值处于领先位置;从空间转移上来看,宝鸡市向西安市转移的价值最大;(3)从土地利用类型方面来看,耕地的生态价值最大,建设用地的生态价值最小,生态服务价值的转移主要发生在耕地、林地和草地之间,其次是耕地和建设用地之间;(4)从整个区域来看,关中-天水经济区南部的生态服务价值高于北部,分布格局存在区域差异,北部需要继续加强对生态环境的保护.

沈阳铁西工业区改造的制度与文化因素

沈阳铁西区是在计划经济体制下形成的国内外著名的城市老工业区,1986年国务院批准为国家计划中唯一的区域性改造试点工程。但长期的技术改造为主策略并未使沈阳铁西工业区摆脱困境。2002年沈阳铁西区和沈阳经济技术开发区合署办公,为铁西工业区改造提供了新的制度动力。本文简要回顾了沈阳铁西区发展改造历程,重点分析了沈阳铁西工业区改造取得突破的制度和文化原因,讨论了“铁西模式”的内在逻辑和潜在问题及其对其它城市老工业区改造的启示。

中国北方三流域河流—沙漠过渡带地表沉积物化学元素空间差异分析

通过对克里雅河、毛布拉格孔兑以及西拉木伦河三流域的河流—沙漠过渡带地表沉积物的7种常量氧化物以及15种微量元素进行因子分析,结果显示:三个流域之间或不同河段因子分析提取的公因子均可以概括为较稳定的铁锰矿物、较不稳定的长石类和方解石(白云石)类等硅酸盐矿物以及稳定的稀土元素和重矿物等类别;河流间因子分析结果表明,自西向东三个流域沿河地表沉积物的化学元素富集与迁移程度呈递增趋势,化学风化程度增强;流域内因子分析结果表明,自上游至下游,样点化学组成均愈变复杂,不同河段或不同河岸沉积物化学元素空间分布规律与其物源、地貌格局以及水分条件等因素有关;自河床至阶地,不同地貌单元地表沉积物化学元素呈相异的递变规律,这与在距离河道远近不同,物源、动力因素的分配不同有关。

塔里木盆地阿—满过渡带中—上奥陶统海相烃源岩的识别及其意义

塔里木盆地阿瓦提凹陷—满加尔凹陷过渡区域(简称阿—满过渡带)多年来一直未发现奥陶系烃源岩,但大量的地球化学资料分析结果却将塔中与塔北地区的油气源区指向了该地区。针对这一现象,对该区构造高部位多口钻井中的中—上奥陶统泥岩样品进行了有机碳含量复查与分析,初步在塔中29井识别出一套海相烃源岩,其有机质丰度(TOC值)可达1.30%,所在地层厚度约为95.0m。在此基础上,进行了烃源岩井震对比及烃源岩发育层位在地震剖面上的对比追踪,最终在阿—满过渡带识别出一套附存于中奥陶统一间房组顶部—上奥陶统吐木休克组的海相烃源岩。该套烃源岩向东相变于古城—轮古东台缘西侧,向南超覆尖灭于塔中Ⅰ号断裂带下盘的满加1井附近,向西超覆尖灭于阿—满过渡带西台缘,向北沉积相变于塔北隆起区羊屋2井南部,烃源岩最大埋深达8 500m。分析认为,该套烃源岩发育于阿—满过渡带碳酸盐岩台地内凹陷环境,其厚度小于150m,应该是塔中与塔北油气区的主力烃源岩之一。

成渝经济区城际轨道交通网空间布局合理性分析——基于空间经济学原理

根据中心地理论及空间经济学的基本原理,首先通过引入冰山运输成本建立了一个以重庆、川南、川东北、成都平原四个城市圈为支撑点的空间菱形经济模型,然后分析了不同的运输成本对产业集聚的影响,最后将成渝经济区城际轨道交通网的空间布局与城市圈的空间菱形模型相结合,阐释了城际轨道交通网规划的合理性。结果表明,城际轨道交通网的空间布局可降低各城市圈之间的运输成本,从而促进经济区内专业化分工和产业集聚、加快成渝城市群一体化进程。

平原丘陵过渡区土壤有机质空间变异及其影响因素

研究土壤有机质(SOM)在平原丘陵过渡区域的空间变异规律及其影响因素对指导农业生产实践具有重要意义。选取平原丘陵过渡区域(江汉平原与鄂西山区)作为研究区,采集500个土壤表层(0~20 cm)样本,利用相关分析和逐步回归分析从14个影响因素中选取与土壤有机质密切相关的7个变量作为解释变量:高程、坡度、坡向、有效铁、容重、砾石度、黏粒含量。利用普通克里格(OK),回归克里格(RK)和地理加权回归克里格(GWRK)方法对研究区土壤有机质含量进行预测,并用平均误差(ME)、平均绝对误差(MAE)、均方根误差(RMSE)、相关系数(r)和不精确度(IP)作为验证指标来检验模型的预测精度。结果表明,GWRK插值结果最优,局部空间回归模型可以更好地表明过渡区域SOM的空间变异规律。且GWR模型的系数空间分布图可以反映环境变量在不同地理位置对SOM的空间非平稳性的影响程度,为探讨SOM在不同地形条件下的主导影响因子提供了依据,同时也为精确模拟过渡地带土壤有机质空间制图提供了重要的参考方法。