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1.
基于垂直带谱的南北过渡带1:5万植被类型图遥感制图研究——以太白山为例 总被引：1，自引：1，他引：1
The compilation of 1:250,000 vegetation type map in the North-South transitional zone and 1:50,000 vegetation type maps in typical mountainous areas is one of the main tasks of Integrated Scientific Investigation of the North-South Transitional Zone of China.In the past,vegetation type maps were compiled by a large number of ground field surveys.Although the field survey method is accurate,it is not only time-consuming,but also only covers a small area due to the limitations of physical environment conditions.Remote sensing data can make up for the limitation of field survey because of its full coverage.However,there are still some difficulties and bottlenecks in the extraction of remote sensing information of vegetation types,especially in the automatic extraction.As an example of the compilation of 1:50,000 vegetation type map,this paper explores and studies the remote sensing extraction and mapping methods of vegetation type with medium and large scales based on mountain altitudinal belts of Taibai Mountain,using multi-temporal high resolution remote sensing data,ground survey data,previous vegetation type map and forest survey data.The results show that:1)mountain altitudinal belts can effectively support remote sensing classification and mapping of 1:50,000 vegetation type map in mountain areas.Terrain constraint factors with mountain altitudinal belt information can be generated by mountain altitudinal belts and 1:10,000 Digital Surface Model(DSM)data of Taibai Mountain.Combining the terrain constraint factors with multi-temporal and high-resolution remote sensing data,ground survey data and previous small-scale vegetation type map data,the vegetation types at all levels can be extracted effectively.2)The basic remote sensing interpretation and mapping process for typical mountains is interpretation of vegetation type-groups→interpretation of vegetation formation groups,formations and subformations→interpretation and classification of vegetation types&subtypes,which is a combination method of top-down method and bottom-up method,not the top-down or the bottom-up classification according to the level of mapping units.The results of this study provide a demonstration and scientific basis for the compilation of large and medium scale vegetation type maps. 相似文献
2.
Demand for food plays an important role in the adjustment of prices for agricultural products and for adjusting agricultural structure.By using the extended linear expenditure system(ELES),we analyzed the food consumption structure of rural residents in the Ganzhou district of Zhangye city,and determined the basic food-consumption demand,the marginal propensity of consumption,the income elasticities of demand,and the own-price and cross-price elasticities of local rural residents,all of which illustrate the influencing factors on food consumption of rural residents and for forecasting the food-consumption structure.Those analyses show the following:the rural residents’ expenditure on household basic food consumption reaches about 7,050.35 Yuan;the marginal propensities of consumption of fruits and vegetables are relatively high(0.062 and 0.106,respectively),followed by meat(0.044);the demands for various foods are increasing as income increases,with the largest income elasticity of demand corresponding to fruits(1.354) and the lowest to cereal(0.310);fruits and vegetables have relatively high own-price elasticities(respectively-0.879 and-0.442),with the cereal having the lowest one(-0.184).An increase in cereal prices would greatly affect demand for other products;with the rising size of rural households,the consumption for meat is decreasing whereas it is increasing for cereal.The improvement of household education levels will lead to the increase of fruit consumption(E = 0.297),which indicates that people will pay more attention to diet and nutrition structure with the improvement of education.Further,although the amount of cereal expenditure is continually growing,the share will be declining with the increase of household income in 2006-2012.For all these reasons,therefore,the government should encourage the cultivation of economic crops and guide the development of stockbreeding to ensure the stability of cereal output.In order to attain the balance between supply and demand,it is important to rationally a 相似文献
3.
Urban resilience is an emerging research topic of urban studies, and its essence is described by the ability of cities to resist, recover, and adapt to uncertain disturbances. This paper constructs a "Size-Density-Morphology" urban ecological resilience evaluation system, uses a coupling coordination degree model to measure the degree of coupling coordination between urbanization and ecological resilience in the Pearl River Delta from 2000 to 2015, and conducts an in-depth discussion on its spatiotemporal characteristics. The results show the following.(1) From 2000 to 2015, the urbanization level of cities in the study area generally increased while the level of ecological resilience declined. The coupling coordination degree between the two systems decreased from basic coordination to basic imbalance.(2) In terms of spatial distribution, the coupling coordination degree between urbanization and ecological resilience of cities presented a circular pattern that centered on the cities at the estuary of the Pearl River and increased toward the periphery.(3) Ecological resilience sub-systems played variable roles in the coupling coordination between urbanization and ecological resilience. Specifically, size resilience mainly played a reverse blocking role;the influence of morphology resilience was generally positive and continued to increase over time;the effect of density resilience was positive and continued to decline and further became negative after falling below zero. The main pathways for achieving coordinated and sustainable development of future urbanization and ecological resilience in the Pearl River Delta include: leading the coordinated development of regions with new urbanization, improving ecological resilience by strictly observing the three areas and three lines, adapting to ecological carrying capacity, and rationally arranging urban green spaces. 相似文献
4.
Climate change resulting from CO_2 emissions has become an important global environmental issue in recent years.Improving carbon emission performance is one way to reduce carbon emissions.Although carbon emission performance has been discussed at the national and industrial levels,city-level studies are lacking due to the limited availability of statistics on energy consumption.In this study,based on city-level remote sensing data on carbon emissions in China from 1992–2013,we used the slacks-based measure of super-efficiency to evaluate urban carbon emission performance.The traditional Markov probability transfer matrix and spatial Markov probability transfer matrix were constructed to explore the spatiotemporal evolution of urban carbon emission performance in China for the first time and predict long-term trends in carbon emission performance.The results show that urban carbon emission performance in China steadily increased during the study period with some fluctuations.However,the overall level of carbon emission performance remains low,indicating great potential for improvements in energy conservation and emission reduction.The spatial pattern of urban carbon emission performance in China can be described as"high in the south and low in the north,"and significant differences in carbon emission performance were found between cities.The spatial Markov probabilistic transfer matrix results indicate that the transfer of carbon emission performance in Chinese cities is stable,resulting in a"club convergence"phenomenon.Furthermore,neighborhood backgrounds play an important role in the transfer between carbon emission performance types.Based on the prediction of long-term trends in carbon emission performance,carbon emission performance is expected to improve gradually over time.Therefore,China should continue to strengthen research and development aimed at improving urban carbon emission performance and achieving the national energy conservation and emission reduction goals.Meanwhile,neighboring cities with different neighborhood backgrounds should pursue cooperative economic strategies that balance economic growth,energy conservation,and emission reductions to realize low-carbon construction and sustainable development. 相似文献
5.
The Yangtze River Delta(YRD) is a region in China with a serious contradiction between economic growth and environmental pollution. Exploring the spatiotemporal effects and influencing factors of air pollution in the region is highly important for formulating policies to promote the high-quality development of urban industries. This study uses the spatial Durbin model(SDM) to analyze the local direct and spatial spillover effects of industrial transformation on air pollution and quantifies the contribution of each factor. From 2008 to 2018, there was a significant spatial agglomeration of industrial sulfur dioxide emissions(ISDE) in the YRD, and every 1% increase in ISDE led to a synchronous increase of 0.603% in the ISDE in adjacent cities. The industrial scale index(ISCI) and industrial structure index(ISTI), as the core factors of industrial transformation, significantly affect the emissions of sulfur dioxide in the YRD, and the elastic coefficients are 0.677 and-0.368, respectively. The order of the direct effect of the explanatory variables on local ISDE is ISCI>ISTI>foreign direct investment(FDI)>enterprise technological innovation(ETI)>environmental regulation(ER)> per capita GDP(PGDP). Similarly, the order of the spatial spillover effect of all variables on ISDE in adjacent cities is ISCI>PGDP>FDI>ETI>ISTI>ER, and the coefficients of the ISCI and ISTI are 1.531 and 0.113, respectively. This study contributes to the existing research that verifies the environmental Kuznets curve in the YRD, denies the pollution heaven hypothesis, indicates the Porter hypothesis, and provides empirical evidence for the formation mechanism of regional environmental pollution from a spatial spillover perspective. 相似文献
6.
The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions vulnerable to climate change is significantly important for formulating adaptive countermeasures. However, with regard to the Yangtze River Watershed, there is currently a lack of research on these aspects from the perspective of natural and anthropogenic factors. To address this issue, in this study, based on the temperature and precipitation records from 717 meteorological stations, the RClim Dex and random forest models were used to assess the spatiotemporal characteristics of climate change and identify mainly the natural and anthropogenic factors influencing climate change hotspots in the Yangtze River Watershed for the period 1958-2017. The results indicated a significant increasing trend in temperature, a trend of wet and dry polarization in the annual precipitation, and that the number of temperature indices with significant variations was 2.8 times greater than that of precipitation indices. Significant differences were also noted in the responses of the climate change characteristics of the sub-basins to anthropogenic and natural factors;the delta plain of the Yangtze River estuary exhibited the most significant climate changes, where 88.89% of the extreme climate indices varied considerably. Furthermore, the characteristics that were similar among the identified hotpots, including human activities(higher Gross Domestic Product and construction land proportions) and natural factors(high altitudes and large proportions of grassland and water bodies), were positively correlated with the rapid climate warming. 相似文献
7.
《地理学报》1947,(Z1)
1. Location and Historical Development Chengtu, the capital city of western Szechwan, is located on the lower part of the Min and Tu alluvial fan (Fig.1) which has an area of about 6,000 sq.km., and is the most fertile irrigated fields of the western China. The autbor discusses the location and site of the city to compare with other cities on the alluvial fan, and finds that the selection and development of Chengtu as a capital city is due chiefly to the reason that it is situated at the terminus point o... 相似文献
8.
中国山地范围界定的初步意见 总被引：8，自引：1，他引：7
中国山地的范围一直缺乏可操作的、准确的量化方法,从而导致对山地及其内部资源、环境、人口和发展问题认识的不全面.同时,准确界定山地范围是实施数字山地战略的一项基础性工作.在前人研究的基础上,采用两种方案确定中国山地范围.方案一:将满足以下两种情况的国土界定为山地,1)海拔≥3 000 m;2)海拔≥1300～3 000 m,同时相对高差>200 m或坡度>25°.根据此标准计算,中国山地面积为4 000 265 km2,占中国陆地面积的41.67%.方案二:根据UNEP-WCMC的标准,将满足下述情况的国土定义为山地,1)海拔≥2 500 m;2)海拔≥1 500～2 500 m,坡度≥2°;3)海拔≥1 000～1 500 m,坡度≥5°或相对高差≥300 m;4)海拔≥300～1 000 m,相对高差≥300 m.根据此标准计算,中国山地面积为4 426 130 km2占中国陆地面积的46.11%.按两种方法计算所得的分省山地面积中,前5名都是西藏、青海、新疆、四川和云南.将两种方案计算的山地面积按高程划分为六级:①300～1 000 m(含300 m),②1 000～1 500 m(含1 000 m),③1 500～2 500 m(含1 500 m),④2 500～3 500 m(含2 500 m),⑤3 500～4 500 m(含3 500 m),⑥≥4 500 m.根据两种方案的定义,海拔3 500 m以上的山地面积相等;除了方案-在300～1 000 m间山地较方案二多324 508 km2外,其余几个级别山地的面积均为方案二大于方案-的山地面积,其中2 500～3 500 m间多133 432 km2,1 500～2 500 m间多336 186 km2,1 000～1 500 m间多282 273 km2. 相似文献
9.
The concept of‘Beautiful China'is a new goal of ecological construction in the new era of socialism and aims to meet the needs of people as they strive for a better life.National land spatial planning is one major component of the Chinese state's overall planning for various spatial types.The concept of‘Beautiful China'is thus a leading goal of Chinese development in the second centenary.The background of this concept aims for‘ecological beauty'as well as the combined beauty of‘economy-politics-culture-society-ecology.'The construction of‘Beautiful China'therefore necessitates a differentiated evaluation index system that is built on the basis of local conditions.This concept is intimately related to land spatial planning and the idea of Beautiful China guides an important direction for this planning which itself provides an important mechanism and spatial guarantee for construction.The establishment of land spatial planning nevertheless needs to strengthen further discussion of the regional system of human-land relationship,point axis system,main functional division,sustainable development,resources and environmental carrying capacity as well as new urbanization,and the rural multi-system.The aim of this paper is to summarize current thinking in land spatial planning,scientifically analyze the natural geographical conditions,the socioeconomic development,the interrelationship of the land space,plan the goal,vision and path of land space,encourage the public to participate in and carry out dynamic evaluation,build an intelligent system platform for land and spatial planning to realize the goal of‘Beautiful China'from a geographical perspective.And they can also present key ideas relating to the compilation and implementation of land spatial planning. 相似文献
10.
A set of circulation indices are defined and calculated to characterize monthly mean polar vortex at 10 hPa geopotential height chart in the Northern Hemisphere,including area-(S),intensity-(P) and center position (λc,φc)-indices by use of 1948-2007 NCEP/NCAR 10 hPa monthly height data.These indices series are used to investigate the seasonal variation and interannual anomaly of polar vortex,along with the relations with global warming,ozone anomaly and Arctic Oscillation (AO).The results show that (1) there is anticyclonic (cyclonic) from Jun.to Aug.(from Sep.to Mar.).The change of spring circulation pattern is slower than that of autumn.(2) S can be replaced by P due to the interannual synchronal variations of the intensity and area for polar vortex.The interannual (interdecadal) variations of P are significant in Jan.(Jul.).(3) The anomalies of system center position in Jan.are more evident than that in Jul.(4) The variations of mean temperature at mid-stratosphere in the vicinity of pole zone in Jan.are different from that in Jul.,but they are synchronal with the corresponding P and not significant correlation with the trend of global warming.However,the relationship between P and total O3 in Jul.are obvious.(5) There is so notable correlation between P and AO that P can represent AO. 相似文献