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1.
森林过火区植被遥感参数的变化与恢复特征分析 总被引：1，自引：0，他引：1
遥感技术可以快速、准确地监测森林火灾火烧迹地的植被遥感参数变化,分析植被对火灾的响应与恢复特征,为防灾减灾决策提供科学依据。本文首先基于森林火灾前后的Landsat5 TM数据,利用差分归一化燃烧指数（the Differential Normalized Burn Ratio,dNBR）来提取2009年澳大利亚维多利亚州火烧迹地的范围,计算过火区面积及火烧强度;其次基于时间序列的全球地表特征参量（Global Land Surface Satellite,GLASS）产品中的叶面积指数（Leaf Area Index,LAI）、吸收光合有效辐射比例（Fraction of Absorbed Photosynthetically Active Radiation,FAPAR）数据,利用距平分析法对比不同火烧强度过火区植被与未过火区植被受森林火灾的影响状况与植被恢复特征。结果表明,森林火灾发生后,LAI、FAPAR值迅速降低,火烧强度越大,LAI、FAPAR下降程度越大,高火烧强度过火区的LAI、FAPAR最大降幅分别为中火烧强度、低火烧强度过火区的1.2、1.3倍;随时间推移,LAI、FAPAR值逐渐上升,在2-3年内恢复至未过火区水平。LAI、FAPAR恢复至未过火区平均水平的时间与森林火灾规模、火烧强度密切相关：维多利亚州森林火灾过火区域中大过火斑块、高火烧强度林地的植被遥感参数恢复时间相比小过火斑块、低火烧强度林地滞后1-2年。植被遥感参数LAI、FAPAR能很好地反映过火区植被的受损状况及恢复过程。 相似文献
2.
Spatial distribution of land cover and vegetation activity along topographic gradient in an arid river valley, SW China 总被引：2，自引：2，他引：0
Anthropogenic activities have become more and more important in characterizing the landscape, but their impacts are still restricted by natural environments. This paper discusses the interactions of anthropogenic activity, vegetation activity and topography through describing the spatial distribution of land cover and vegetation activity （represented by Normalized Difference Vegetation Index, NDVI） along topographic gradient in a mountainous area of southwestern China. Our results indicate that the existing landscape pattern is controlled by anthropogenic activities as well as topographic factors. Intensive anthropogenic activities mainly occur in areas with relatively low elevation, gentle and concave slopes, as these areas are easy and convenient to attain for human. Because of the destruction by human, some land cover types （mainly grassland and shrub） are only found in relatively harsher environments. This study also finds that topographic wetness index （W） used in other places only reflects runoff generation capacity, but not indicate the real spatial pattern of soil water content in this area. The relationships between NDVI and W, and NDVI and length slope factor （LSF） show that runoff and erosion have complex effects on vegetation activity. Greater values of W and LSF will lead to stronger capacity to produce runoff and transport sediment, and thereby increase soil water content and soil deposition, whereas beyond a certain threshold runoff and erosion are so strong that they would destruct vegetation growth. This study provides information needed to successfully restore native vegetation, improve land management, and promote sustainable development in mountainous areas, especially for developing regions. 相似文献
3.
《山地科学学报》2017,(3)
With the well-being trends to pursue a healthy life, mountain ginseng(Panax ginseng) is rising as one of the most profitable forest products in South Korea. This study was aimed at evaluating a new methodology for identifying suitable sites for mountain ginseng cultivation in the country. Forest vegetation data were collected from 46 sites and the spatial distribution of all sites was analyzed using GIS data for topographic position, landform, solar radiation, and topographic wetness. The physical and chemical properties of the soil samples, including moisture content, p H, organic matter, total nitrogen, exchangeable cations, available phosphorous, and soil texture, were analyzed. The cultivation suitability at each site was assessed based on the environmental conditions using logistic regression(LR) and geographically weighted logistic regression(GWLR) and the results of both methods were compared. The results show that the areas with northern aspect and higher levels of solar radiation, moisture content, total nitrogen, and sand ratio are more likely to be identified as suitable sites for ginseng cultivation. In contrast to the LR, the spatial modeling with the GWLR results in an increase in the model fitness and indicates that a significant portion of spatialautocorrelation in the data decreases. A higher value of the area under the receiver operating characteristic(ROC) curve presents a better prediction accuracy of site suitability by the GWLR. The geographically weighted coefficient estimates of the model are nonstationary, and reveal that different site suitability is associated with the geographical location of the forest stands. The GWLR increases the accuracy of selecting suitable sites by considering the geographical variations in the characteristics of the cultivation sites. 相似文献
4.
With the well-being trends to pursue a healthy life, mountain ginseng (Panax ginseng) is rising as one of the most profitable forest products in South Korea. This study was aimed at evaluating a new methodology for identifying suitable sites for mountain ginseng cultivation in the country. Forest vegetation data were collected from 46 sites and the spatial distribution of all sites was analyzed using GIS data for topographic position, landform, solar radiation, and topographic wetness. The physical and chemical properties of the soil samples, including moisture content, pH, organic matter, total nitrogen, exchangeable cations, available phosphorous, and soil texture, were analyzed. The cultivation suitability at each site was assessed based on the environmental conditions using logistic regression (LR) and geographically weighted logistic regression (GWLR) and the results of both methods were compared. The results show that the areas with northern aspect and higher levels of solar radiation, moisture content, total nitrogen, and sand ratio are more likely to be identified as suitable sites for ginseng cultivation. In contrast to the LR, the spatial modeling with the GWLR results in an increase in the model fitness and indicates that a significant portion of spatial autocorrelation in the data decreases. A higher value of the area under the receiver operating characteristic (ROC) curve presents a better prediction accuracy of site suitability by the GWLR. The geographically weighted coefficient estimates of the model are non-stationary, and reveal that different site suitability is associated with the geographical location of the forest stands. The GWLR increases the accuracy of selecting suitable sites by considering the geographical variations in the characteristics of the cultivation sites. 相似文献
5.
随机森林方法支持的复杂地形区土地利用/土地覆被分类研究 总被引：2，自引：0，他引：2
随机森林方法目前已经成为遥感分类机器学习中一种有效方法,探索基于中等分辨率的Landsat卫星数据与随机森林方法相结合对复杂地形区长时间序列数据的获取及土地利用/土地覆被变化及模拟研究是非常有意义的。本文基于Landsat8OLI卫星多光谱数据,采用随机森林分类方法对青海省湟水流域复杂地形区土地利用类型进行了分类研究。针对复杂地形区域的情况,将研究区进行地理分区,根据每个分区的特点,选择相应的地形特征参数,并通过提取Landsat 8数据的光谱信息与纹理信息构建最优特征集,探索随机森林方法在复杂地形区土地利用分类的适用性。结果表明：使用Landsat8OLI数据进行随机森林分类,能较好地得到湟水流域复杂地形区域的土地利用类型结果;光谱、地形及纹理信息的结合在不同分区的表现结果不同。在脑山区光谱与地形信息结合能使随机森林分类效果最佳,总体精度达到91.33%,Kappa系数为0.886;而在浅山区与川水区综合考虑光谱、地形、纹理信息进行随机森林分类效果最佳,浅山区与川水区总体精度分别达到92.09%和87.85%,Kappa系数分别为0.902和0.859;利用随机森林算法进行优化选择纹理特征组合可以在保证分类精度的同时能够快速地提取土地利用类型信息,为复杂地形区土地利用类型的区分提供了实际可行的方法。 相似文献
6.
As a hot topic in Landscape Ecology study, ecological connectivity is an important indicator for regional land sustainable use and biological protection. This paper conducted a systematic assessment of ecological connectivity using remote sensing images of Dongshan Island in 1994, 2003 and 2011. Based on least-cost modelling, the method takes into consideration the type of barrier, the distance impact, and the adjacent land use types to obtain the Barrier Effect Index (BEI) and Ecological Connectivity Index (ECI). The application of this method to Dongshan Island showed the ecological connectivity index (ECI) was low in 1994, improved in 2003, and decreased significantly in 2011. The results of the dynamic analysis of landscape structure showed farmland and roads were the main landscape classes that caused the low observed ECI in 1994 and 2003; these tended to divide the landscape and cause fragmentation. Construction land and roads were the main landscape classes resulting in low ECI in 2011, while forest and grassland had a high ECI. Trajectory analysis showed ECI tended to decrease in the low mountain forest zone of the northwestern and southeastern parts of Dongshan Island as well as in the coastal protection forest area. The areas where ECI became high were located in the northeastern part of Dongshan Island where cities and towns are concentrated with high human populations. Therefore, rapid urbanization has been the most important factor driving changes in landscape structure and patterns during the last 17 years on Dongshan Island. The approach not only assists us in revealing the driving mechanism of landscape dynamics from another aspect, but also can assess the impacts of regional and urban plans on landscape structure and function. 相似文献
7.
《山地科学学报》2020,(2)
Evapotranspiration(ET) is a crucial part of the global hydrological cycle, and quantifying ET components is significant for understanding the global water cycle and energy balance. However, there is no consensus on the value of ET components, especially in topographic abrupt change zone, such as eastern margin of the Qinghai-Tibet Platea, where values of ET changes along the altitudinal gradients. Our aim is to explore the influencing factors in partitioning evapotranspiration and how ET components change with increasing elevations. A novel approach was proposed to estimate ET components by adding net solar radiation(Rn) instead of the vapor pressure deficit(VPD) into the underlying water use efficiency(u WUE) model based on one-year continuous measurements of flux data along the elevation gradient on Mount Gongga. Correlation analysis shows that the u WUE model's performance can be improved significantly by considering Rn instead of VPD, with correlation coefficients increasing by 35%-64%. The ratios of transpiration(T) to ET(T/ET) were 0.47, 0.48, 0.50 and 0.35 for the deciduous broadleaf forest(BF), mixed coniferous and deciduous broadleaf forest(MF), evergreen needle forest(ENF) and shrub land(SL), respectively. Leaf area index(LAI) and air temperature(Ta) were the two main controlling factors in determining T/ET during the growing season and at an annual scale, while Rn and Ta played more important roles during the dormant season. This study highlights the importance of incorporating Rn in partitioning evapotranspiration by using the water use efficiency(WUE) method in a humid mountainous region, which can improve the estimation of T/ET on a global scale. 相似文献
8.
高速公路的快速发展在推动经济发展的同时,也对区域的生态环境产生重要的影响。在地理信息系统的支持下,本研究以北京市高速公路网10 km缓冲区为研究区域,利用缓冲区分析、空间分析、统计分析等方法探讨了高速公路周边土地利用变化对景观格局的影响规律。结果表明：① 北京市高速公路周边的土地利用类型主要以建设用地、耕地、林地为主,土地利用变化以耕地向建设用地转入最为显著;② 空间变化上,各缓冲区内土地利用变化以林地、耕地、建设用地的相互转移为主,随着与高速公路的距离增大,土地利用类型从以耕地、建设用地为主逐渐转变为以林地、耕地为主;③ 2005-2015年,各类景观的景观指数变化差异明显,其中水域的斑块密度与分离度指数变化幅度最大,耕地的形状指数增加最快,建设用地的分离度指数减少最多,这与相应的土地利用变化密切相关;④ 基于土地利用变化,北京市高速公路网对周边景观格局的影响范围约为6 km,其中林地转入建设用地以及建设用地与耕地的相互转移是引起公路周边景观空间变化差异的主要原因。 相似文献
9.
Based on forest inventory data (FID) at sublot level,we estimated the carbon sequestration in forest vegetation of Beijing,China in 2009.In this study,the carbon sequestration in forest vegetation at sublot level was calculated based on net biomass production (ΔB) which was estimated with biomass of each sublot and function relationships between ΔB and biomass.The biomass of forested land was calculated with biomass expansion factors (BEFs) method,while those of shrub land and other forest land types were estimated with biomass,coverage and height of referred shrubs and shrub coverage and height of each sublot.As one of special forested land types,the biomass of economic tree land was calculated with biomass per tree and tree number.The variation of carbon sequestration in forest vegetation with altitude,species and stand age was also investigated in this study.The results indicate that the carbon sequestration in forest vegetation in Beijing is 4.12 × 106 tC/yr,with the average rate of 3.94 tC/(ha·yr).About 56.91% of the total carbon sequestration in forest vegetation is supported by the forest in the plain with an altitude of < 60 m and the low mountainous areas with an altitude from 400 m to 800 m.The carbon sequestration rate in forest vegetation is the highest in the plain area with an altitude of < 60 m and decreased significantly in the transitional area from the low plain to the low mountainous area with an altitude ranging from 200 m to 400 m due to intensive human disturbance.The carbon sequestration of Populus spp.forest and Quercus spp.forest are relatively higher than those of other plant species,accounting for 25.33% of the total.The carbon sequestration in vegetation by the forest of < 40 years amounts to 45.38% of the total.The carbon sequestration rate in forest vegetation peaks at the stand age of 30–40 years.Therefore,it would be crucial for enhancing the capability of carbon sequestration in forest vegetation to protect the forest in Beijing,to limit human disturbance in the transitional area from the plain to the low mountain area,and to foster the newly established open forest. 相似文献
10.
Land use and land cover change on slope in Qiandongnan prefecture of Southwest China 总被引：2，自引：0，他引：2
This study uses DEM(Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes.The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types(farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from 0° to 25°, while a quantity of forest were transformed from the other land use types on 25° from 1993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density(PD) value, Largest Patch Index(LPI), Shannon's Diversity Index(SHDI), Area-Weighted Mean Shape Index(AWMSI) and Contagion Index(CONTAG). The results of metricsanalysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value. 相似文献
11.
森林景观格局分析是森林景观优化配置与实施规划的基础。本文以森林资源二类调查数据为基础,采用森林景观定量空间分析方法,在自主开发而成的森林景观可视化系统VisForest支持下,利用VS2008开发平台、ArcEngine组件与OSG图形渲染引擎,集成景观指数计算模型和地理信息系统的分析方法,形成森林景观格局分析与景观三维可视化模拟系统,实现了景观格局分析的定量化和景观可视化;并以闽侯县白沙国有林场2013年的数据为例,按优势树种划分森林景观类型,计算分析了景观组成结构、斑块特征和景观异质性等。结果表明,杉木林、马尾松林、湿地松林、木荷林、非林地是白沙林场的优势景观类型,总体景观类型丰富、景观异质性较高;木荷作为隔离带树种,以小面积狭长斑块居多,其形状指数和分形维数最大,斑块形状复杂而不规则;森林景观的三维可视化模拟为研究景观格局提供了一个直观、交互的展示平台。 相似文献
12.
Zongming Wang Yubo Zhang Bai Zhang Kaishan Song Zhixing Guo Dianwei Liu Fang Li 《中国地理科学(英文版)》2008,18(2):137-145
The landscape pattern of Da＇an County, Northeast China has undergone significant changes since the 1950s as a result of climatic change and human activities. The aim of this paper is to quantitatively study landscape pattern and its spatial dynamics of Da＇an County at the landscape level over the nearly 50-year span. Patch dynamics were examined according to land use and land cover change processes built from a series of images, as well as topographic maps, and temporal patterns built from landscape pattern metrics. The transition matrix of landscape patch types and changes of various landscape metrics were applied. The results showed that, from 1956 to 2000, the landscape within the study area had undertaken a complicated evolution in landscape structure and composition. The outstanding characteristic is that saline-alkali land increased and grassland decreased. As some smaller patches amalgamated, the heterogeneity of patch decreased. All those changes were the synthetic result of both climatic and anthropogenic influences, but the predominant factor was different in different parts. In the southern part of the study area, the landscape pattern changes resulted from the modification of climate obviously, while in the northern part, the landscape pattern changes were mainly caused by human activities, such as the conversion between farmland and saline-alkali land. This phenomenon showed that human activities played more important role in the north than in the south of Da＇an County. 相似文献
13.
Carbon emissions from forest fires are considered an important factor of ecosystem carbon balance and global climate change. Carbon emissions from Japanese red pine stands (Pinus densiflora S. et Z.) burned by crown fire were estimated at Mt. Palgong in Daegu Metropolitan City, and crown fuel characteristics, including crown bulk density, crown base height, and fuel moisture content of Japanese red pine, were analyzed. Total biomass combusted was calculated by subtracting the biomass of burned stands from that of unburned stands exhibiting similar stand structures and site environments. Ten trees in the unburned area and five trees in the burned area were cut by using direct harvesting techniques to estimate crown layer biomass. All biomass sampled was oven-dried and weighed. The dry weight ratios of stems, branches, and needles were 70%, 21%, and 9%, respectively. The available fuel load susceptible to combustion during the crown fire spread was equivalent to 55% of the crown layer biomass. The crown bulk density was 0.24 kg/ m 3 on average. The estimated amount of CO 2 was 23,454 kg CO 2 /ha for the crown layer. These results will be useful for calculating the amount of CO 2 emitted from forest fires and for developing a forest carbon model in P. densiflora forests. 相似文献
14.
Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution and impacts of wild boars were examined using a questionnaire survey and spatial analysis.The results showed that:(1)The density of farmer settlements is low and most peasants'households are located on the forest edge.Due to large-scale labor migration,a high proportion of farmland(25.85%)has been abandoned and an even higher proportion of farmland(40.48%)has been returned to forest.(2)The probability of wild boar damage to peasant households was 67.96%.Yields of corn and sweet potato decreased by 24.87%and 28.24%,respectively,with a total economic loss of approximately 2,590,100 RMB/yr in the Wuqiaohe basin.Sixty-five percent of the affected cultivatedlands were located within approximately 150 m of the forest edges.(3)The wild boar damage coefficient was significantly and negatively correlated with the distance between the peasants'household and the forest edge,the density of the settlements,and the area of cultivated land.The wild boar damage coefficient shows a significant positive correlation with the area of farmland returned to forest.(4)The damage activity caused by wild boars began to occur7-8 years ago,and the destruction has been more frequently and seriously observed in the last 4-5 years.(5)We make suggestions for wild boar control and management measures including developing a compensation policy.The compensation standard is related to the land area returning from farmland to forests and the actual cultivated land area. 相似文献
15.
本研究利用厦门市4个季节的Landsat-5 TM遥感影像和气象资料,反演地表净辐射通量,进而分析其季相变化特征;使用景观格局指数表征和描述地表覆盖的空间组成与配置,采用相关分析、偏相关分析、逐步回归和方差分解相结合的方法,从多季节角度研究地表覆盖格局对地表净辐射通量的影响。结果表明：① 厦门市地表净辐射通量平均值夏季最高,春季次之,秋季和冬季较低,地表净辐射通量在水体和林地区域较高,建设用地和裸地等其他地表覆盖类型区域较低;② 地表覆盖的空间配置对地表净辐射通量没有显著影响;③ 地表覆盖的空间组成对地表净辐射通量产生重要影响,全年内林地和裸地所占面积比例对地表净辐射通量的影响最显著,林地所占面积比例是影响和解释地表净辐射通量跨季节差异的最重要和持续有效的因素。该研究加深了关于地表覆盖格局对地表净辐射通量的影响的科学认知,有助于探索城市热岛的形成和演变机制,也可为城市规划和可持续发展提供理论依据和实践指导。 相似文献
16.
This study was performed to estimate the emission of non-CO 2 greenhouse gases(GHGs) from biomass burning at a large fire area.The extended methodology adopted the IPCC Guidelines(2003) equation for use on data from the Samcheok forest fire gathered using 30 m resolution Landsat TM satellite imagery,digital forest type maps,and growing stock information per hectare by forest type in 1999.Normalized burn ratio(NBR) technique was employed to analyze the area and severity of the Samcheok forest fire that occurred in 2000.The differences between NBR from pre-and post-fire datasets are examined to determine the extent and degree of change detected from burning.The results of burn severity analysis by dNBR of the Samcheok forest fire area revealed that a total of 16,200 ha of forest were burned.The proportion of the area characterized by a ’Low’ burn severity(dNBR below 152) was 35%,with ’Moderate’(dNBR 153-190) and ’High’(dNBR 191-255) areas were at 33% and 32%,respectively.The combustion efficiency for burn severity was calculated as 0.43 for crown fire where burn severity was ’High’,as 0.40 for ’Moderate’ severity,and 0.15 for ’Low’ severity surface fire.The emission factors for estimating non-CO 2 GHGs were separately applied to CO 130,CH 4 9,NO x 0.7 and N 2 O 0.11.Non-CO 2 GHGs emissions from biomass burning in the Samcheok forest fire area were estimated to be CO 44.100,CH 4 3.053,NO x 0.238 and N 2 O 0.038 Gg. 相似文献
17.
The altitudinal pattern of vegetation is usually identified by field surveys,however,these can only provide discrete data on a local mountain.Few studies identifying and analyzing the altitudinal vegetation pattern on a regional scale are available.This study selected central Inner Mongolia as the study area,presented a method for extracting vegetation patterns in altitudinal and horizontal directions.The data included a vegetation map at a 1∶1 000 000 scale and a digital elevation model at a 1∶250 000 scale.The three-dimensional vegetation pattern indicated the distribution probability for each vegetation type and the transition zones between different vegetation landscapes.From low to high elevations,there were five vegetation types in the southern mountain flanks,including the montane steppe,broad-leaved forest,coniferous mixed forest,montane dwarf-scrub and sub-alpine shrub-meadow.Correspondingly,only four vegetation types were found in the northern flanks,except for the montane steppe.This study could provide a general model for understanding the complexity and diversity of mountain environment and landscape. 相似文献
18.
Effects of topography and land use on woody plant species composition and beta diversity in an arid Trans-Himalayan landscape,Nepal 总被引：1，自引：1，他引：0
Distribution patterns of plant species are believed to be impacted by small-scale habitat heterogeneity. However, there have been few comparative studies examining how woody vegetation composition and diversity varies with aspects of different orientations in the Trans-Himalayan region at a local scale. Here, we examined the effects of incoming solar radiation on variation in woody species composition and compared the diversity between the northeast- and southwest-facing slopes in a Trans-Himalayan valley of Nepal. We also examined the implicit interactions between slope orientation and land use in determining the compositional variations between the slopes. We selected two pairs of northeast- and southwest-facing slopes where the first pair has a similar land use and differs in exposure only（Pisang site） while the other pair has clear differences in land use in addition to slope exposure（Braka site）. In each site, we sampled 72 plots（36 on each slope） in which the presence and absence of woody species, environmental variables, and disturbance were recorded. Correspondence Analysis（CA） results suggested that the woody species composition significantly varied between northeast- and southwest-facing slopes at both sites, and was significantly correlated with measured environmental variables such as radiation index, altitude, and canopy openness. In the Braka site,mean alpha diversity was significantly higher on southwest-facing slopes. In contrast, beta diversity and gamma diversity were greater on northeast-facing slopes at both sites. Our results suggest that topographic variables（e.g., radiation index） affect species composition between the slopes, likely due to their influence on small scale abiotic environmental variables. However, the effects of land use, such as livestock browsing/grazing may interact with the effects of slope exposure, effectively reducing differences in species composition within slopes but enhancing the differences in beta diversity between contrasting slopes in the Br 相似文献
19.
遥感地表能量信息可揭示城市地表要素的地表能量综合响应特征和作用关系特征,客观地反映了城市实体空间、开敞空间及其开放空间网络的格局和变化。本文从重庆城市地表能量响应的基本网格单元和研究区尺度,分析城市地表要素对城市热环境的贡献,并结合与“国际宜居城市”——西雅图的对比,探讨城市化过程中地表要素类型改变对城市热环境的影响及其变化和规律。结果表明：① 在基本网格单元和区域尺度层面,城市地表能量的平衡取决于地表要素中实体空间和开敞空间布局的合理性与稳定性;② 在城市大规模的硬质化区域,建筑实体的垂直体量相对于其水平体量及其组团格局,对于地表能量的聚集、改变具有较高的敏感性;③ 地表要素对城市热环境的影响若达到同等贡献指数（绝对值）程度,基本网格单元的开敞空间比例需要高于实体空间;④ 开敞空间基本网格单元的林地和水体类型所占比例达到20%时,地表能量的减幅明显;⑤ 实体空间基本网格单元的在建/工业用地要素类型所占比例超过5%,以及高密度建设用地所占比例达到30%时,地表能量的增幅明显。本研究旨在从城市地物实体地表能量的体量与空间关系角度,为建设基于城市更新的城市规划和城市设计提供科学依据。 相似文献
20.
土地类型研究在综合自然地理学中具有重要的地位和意义。该研究虽在国内外已取得很多成果以及制图实践,但仍然有3个问题有待解决：（1）如何对土地类型进行系统分级、分几级;（2）如何选择土地类型各级指标要素;（3）如何利用多源数据进行计算机自动跨尺度土地类型制图。针对上述问题,本文基于国家标准地理格网提出一种土地类型指标数据库建设方案,即构建4级标准地理格网模型,以各级格网单元作为指标表达载体,选择土地类型研究普遍采用的地带、地貌、土壤和植被4要素,进行多级标准地理格网指标库建设框架设计。通过设计与分析,指出多级地理格网分类体系有其物质基础,即地球科学各学科都具有多尺度研究特征,各学科所具有的分类体系层次性可用多级格网来表达,尤其是影响土地类型分类分级系统的地貌、土壤、植被3个要素间存在相互作用,决定了三者分类体系分级数目和各级格网单元尺度应一致或相近。因此,本文基于标准格网体系,给出了一个土地类型指标数据库建设框架,以期用于土地类型研究与制图格网数据库平台的构建,为进一步开展土地类型制图实践研究提供新思路。 相似文献