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1.
三江源地区气候变化及其对径流的驱动分析(英文)   总被引:3,自引:3,他引:3  
Based on the precipitation and temperature data of the 12 meteorological stations in the "Three-River Headwaters" region and the observed runoff data of Zhimenda in the headwater sub-region of the Yangtze River, Tangnaihai in the headwater sub-region of the Yellow River and Changdu in the headwater sub-region of the Lancang River during the period 1965-2004, this paper analyses the trends of precipitation, temperature, runoff depth and carries out significance tests by means of Mann-Kendall-Sneyers sequential trend test. Makkink model is applied to calculate the potential evaporation. The runoff model driven by precipitation and potential evaporation is developed and the influence on runoff by climate change is simulated under different scenarios. Results show that during the period 1965-2004 the temperature of the "Three-River Headwaters" region is increasing, the runoff of the three hydrological stations is decreasing and both of them had abrupt changes in 1994, while no significant trend changes happen to the precipitation. The runoff model suggests that the precipitation has a positive effect on the runoff depth, while the potential evaporation plays a negative role. The influence of the potential evaporation on the runoff depth of the Lancang River is found to be the significant in the three rivers; and that of the Yellow River is the least. The result of the scenarios analysis indicates that although the precipitation and the potential evaporation have positive and negative effects on runoff relatively, fluctuated characteristics of individual effect on the runoff depth in specific situations are represented.  相似文献   

2.
近30年中国东北地区玉米种植体系的时空动态分析(英文)   总被引:4,自引:1,他引:4  
Understanding crop patterns and their changes on regional scale is a critical requirement for projecting agro-ecosystem dynamics. However, tools and methods for mapping the distribution of crop area and yield are still lacking. Based on the cross-entropy theory, a spatial production allocation model(SPAM) has been developed for presenting spatio-temporal dynamics of maize cropping system in Northeast China during 1980–2010. The simulated results indicated that(1) maize sown area expanded northwards to 48°N before 2000, after that the increased sown area mainly occurred in the central and southern parts of Northeast China. Meanwhile, maize also expanded eastwards to 127°E and lower elevation(less than 100 m) as well as higher elevation(mainly distributed between 200 m and 350 m);(2) maize yield has been greatly promoted for most planted area of Northeast China, especially in the planted zone between 42°N and 48°N, while the yield increase was relatively homogeneous without obvious longitudinal variations for whole region;(3) maize planting density increased gradually to a moderately high level over the investigated period, which reflected the trend of aggregation of maize cultivation driven by market demand.  相似文献   

3.
The quantity and spatial pattern of farmland has changed in China, which has led to a major change in the production potential under the influence of the national project of ecological environmental protection and rapid economic growth during 1990–2010. In this study, the production potential in China was calculated based on meteorological, terrain elevation, soil and land-use data from 1990, 2000 and 2010 using the Global Agro-ecological Zones model. Then, changes in the production potential in response to farmland changes from 1990 to 2010 were subsequently analyzed. The main conclusions were the following. First, the total production potential was 1.055 billion tons in China in 2010. Moreover, the average production potential was 7614 kg/ha and showed tremendous heterogeneity in spatial pattern. Total production in eastern China was high, whereas that in northwestern China was low. The regions with high per unit production potential were mainly distributed over southern China and the middle and lower reaches of the Yangtze River. Second, the obvious spatiotemporal heterogeneity in farmland changes from 1990 to 2010 had a significant influence on the production potential in China. The total production potential decreased in southern China and increased in northern China. Furthermore, the center of growth of the production potential moved gradually from northeastern China to northwestern China. The net decrease in the production potential was 2.97 million tons, which occupied 0.29% of the national total actual production in 2010. Third, obvious differences in the production potential in response to farmland changes from 1990 to 2000 and from 2000 to 2010 were detected. The net increase in the production potential during the first decade was 10.11 million tons and mainly distributed in the Northeast China Plain and the arid and semi-arid regions of northern China. The net decrease in the production potential during the next decade was 13.08 million tons and primarily distributed in the middle and lower reaches of the Yangtze River region and the Huang-Huai-Hai Plain. In general, the reason for the increase in the production potential during the past two decades might be due to the reclamation of grasslands, woodlands and unused land, and the reason for the decrease in the production potential might be urbanization that occupied the farmland and Green for Grain Project, which returned farmland to forests and grasslands.  相似文献   

4.
中国畜禽养殖的空间分析及分区研究(英文)   总被引:2,自引:1,他引:2  
The capacity of livestock breeding in China has increased rapidly since 1949, and the total output of meat, poultry and eggs maintains the world’s top first in recent 20 years. Livestock emissions and pollution is closely associated with its population and spatial distribution. This paper aims to investigate the spatial patterns of livestock and poultry breeding in China. Using statistical yearbook and agricultural survey in 2007, the county-level populations of livestock and poultry are estimated as equivalent standardized pig index (ESP), per cultivated land pig index (PCLP) and per capita pig index (PCP). With the help of spatial data analysis (ESDA) tools in Geoda and ArcGIS software, especially the Moran’s I and LISA statistics, the nationwide global and local clustering trends of the three indicators are examined respectively. The Moran’s I and LISA analysis shows that ESP and PCP are significantly clustering both globally and locally. However, PCLP is clustering locally but not significant globally. Furthermore, the thematic map series (TMS) and related gravity centers curve (GCC) are introduced to explore the spatial patterns of livestock and poultry in China. The indicators are classified into 16 levels, and the GCCs for the three indicators from level 1 to 16 are discussed in detail. For districting purpose, each interval between gravity centers of near levels for all the three indicators is calculated, and the districting types of each indicator are obtained by merging adjacent levels. The districting analysis for the three indicators shows that there exists a potential uniform districting scheme for China’s livestock and poultry breeding. As a result, the China’s livestock and poultry breeding would be classified into eight types: extremely sparse region, sparse region, relatively sparse region, normally sparse region, normal region, relatively concentrated region, concentrated region and highly concentrated region. It is also found that there exists a clear demarcation line between the concentrated and the sparse regions. The line starts from the county boundary between Xin Barag Left Banner and Xin Barag Right Banner, Inner Mongolia Autonomous Region to the west coast of Dongfang County, Hainan Province.  相似文献   

5.
Despite the observed increase in global temperature, observed pan evaporation in many regions has been decreasing over the past 50 years, which is known as the "pan evaporation paradox". The "pan evaporation paradox" also exists in the Tibetan Plateau, where pan evaporation has decreased by 3.06 mm a-2 (millimeter per annum). It is necessary to explain the mechanisms behind the observed decline in pan evaporation because the Tibetan Plateau strongly influences climatic and environmental changes in China, Asia and even in the Northern Hemisphere. In this paper, a derivation based approach has been used to quantitatively assess the contribution rate of climate factors to the observed pan evaporation trend across the Tibetan Plateau. The results showed that, provided the other factors remain constant, the increasing temperature should have led to a 2.73 mm a-2 increase in pan evaporation annually, while change in wind speed, vapor pressure and solar radiation should have led to a decrease in pan evaporation by 2.81 mm a-2, 1.96 mm a-2 and 1.11 mm a-2 respectively from 1970 to 2005. The combined effects of the four climate variables have resulted in a 3.15 mm a-2 decrease in pan evaporation, which is close to the observed pan evaporation trend with a relative error of 2.94%. A decrease in wind speed was the dominant factor for the decreasing pan evaporation, followed by an increasing vapor pressure and decreasing solar radiation, all of which offset the effect of increasing temperature across the Tibetan Plateau.  相似文献   

6.
江河源区NDVI时空变化及其与气候因子的关系(英文)   总被引:2,自引:3,他引:2  
The source regions of the Yangtze and Yellow rivers are important water conservation areas of China. In recent years, ecological deterioration trend of the source regions caused by global climate change and unreasonable resource development increased gradually. In this paper, the spatial distribution and dynamic change of vegetation cover in the source regions of the Yangtze and Yellow rivers are analyzed in recent 10 years based on 1-km resolution multitemporal SPOTVGT-DN data from 1998 to 2007. Meanwhile, the correlation relationships between air temperature, precipitation, shallow ground temperature and NDVI, which is 3×3 pixel at the center of Wudaoliang, Tuotuohe, Qumalai, Maduo, and Dari meteorological stations were analyzed. The results show that the NDVI values in these two source regions are increasing in recent 10 years. Spatial distribution of NDVI which was consistent with hydrothermal condition decreased from southeast to northwest of the source regions. NDVI with a value over 0.54 was mainly distributed in the southeastern source region of the Yellow River, and most NDVI values in the northwestern source region of the Yangtze River were less than 0.22. Spatial changing trend of NDVI has great difference and most parts in the source regions of the Yangtze and Yellow rivers witnessed indistinct change. The regions with marked increasing trend were mainly distributed on the south side of the Tongtian River, some part of Keqianqu, Tongtian, Chumaer, and Tuotuo rivers in the source region of the Yangtze River and Xingsuhai, and southern Dari county in the source region of the Yellow River. The regions with very marked increasing tendency were mainly distributed on the south side of Tongtian Rriver and sporadically distributed in hinterland of the source region of the Yangtze River. The north side of Tangula Range in the source region of the Yangtze River and Dari and Maduo counties in the source region of the Yellow River were areas in which NDVI changed with marked decreasing tendency. The NDVI change was980 Journal of Geographical Sciences positively correlated with average temperature, precipitation and shallow ground temperature. Shallow ground temperature had the greatest effect on NDVI change, and the second greatest factor influencing NDVI was average temperature. The correlation between NDVI and shallow ground temperature in the source regions of the Yangtze and Yellow rivers increased significantly with the depth of soil layer.  相似文献   

7.
东莞地区土地利用变化预测的CBR和CA方法对比研究(英文)   总被引:3,自引:0,他引:3  
Many studies on land use change(LUC),using different approaches and models,have yielded good results.Applications of these methods have revealed both advantages and limitations.However,LUC is a complex problem due to influences of many factors,and variations in policy and natural conditions.Hence,the characteristics and regional suitability of different methods require further research,and comparison of typical approaches is re-quired.Since the late 1980s,CA has been used to simulate urban growth,urban sprawl and land use evolution successfully.Nowadays it is very popular in resolving the LUC estimating problem.Case-based reasoning(CBR),as an artificial intelligence technology,has also been employed to study LUC by some researchers since the 2000s.More and more researchers used the CBR method in the study of LUC.The CA approach is a mathematical system con-structed from many typical simple components,which together are capable of simulating complex behavior,while CBR is a problem-oriented analysis method to solve geographic problems,particularly when the driving mechanisms of geographic processes are not yet understood fully.These two methods were completely different in the LUC research.Thus,in this paper,based on the enhanced CBR model,which is proposed in our previous research(Du et al.2009),a comparison between the CBR and CA approaches to assessing LUC is presented.LUC in Dongguan coastal region,China is investigated.Applications of the im-proved CBR and the cellular automata(CA) to the study area,produce results demonstrating a similarity estimation accuracy of 89% from the improved CBR,and 70.7% accuracy from the CA.From the results,we can see that the accuracies of the CA and CBR approaches are both >70%.Although CA method has the distinct advantage in predicting the urban type,CBR method has the obvious tendency in predicting non-urban type.Considering the entire ana-lytical process,the preprocessing workload in CBR is less than that of the CA approach.As such,it could be concluded that the CBR approach is more flexible and practically useful than the CA approach for estimating land use change.  相似文献   

8.
According to the highway data and some socioeconomic data of 1990, 1994, 2000, 2005 and 2009 of county units in the Pearl River Delta, this paper measured urban integrated power of different counties in different years by factor analysis, and estimated each county’s potential in each year by means of expanded potential model. Based on that, the spatio-temporal association patterns and evolution of county potential were analyzed using spatio-temporal autocorrelation methods, and the validity of spatio-temporal association patterns was verified by comparing with spatial association patterns and cross-correlation function. The main results are shown as follows:(1) The global spatio-temporal association of county potential showed a positive effect during the study period. But this positive effect was not strong, and it had been slowly strengthened during 1994–2005 and decayed during 2005–2009. The local spatio-temporal association characteristics of most counties’ potential kept relatively stable and focused on a positive autocorrelation, however, there were obvious transformations in some counties among four types of local spatio-temporal association(i.e., HH, LL, HL and LH).(2) The distribution difference and its change of local spatio-temporal association types of county potential were obvious. Spatio-temporal HH type units were located in the central zone and Shenzhen-Dongguan region of the eastern zone, but the central spatio-temporal HH area shrunk to the Guangzhou-Foshan core metropolitan region only after 2000; the spatio-temporal LL area in the western zone kept relatively stable with a surface-shaped continuous distribution pattern, new LL type units emerged in the south-central zone since 2005, the eastern LL area expanded during 1994–2000, but then gradually shrunk and scattered at the eastern edge in 2009; the spatio-temporal HL and LH areas varied significantly.(3) The local spatio-temporal association patterns of county potential among the three zones presented significant disparity, and obvious difference between the eastern and central zones tended to decrease, whereas that between the western zone and the central and eastern zones further expanded.(4) Spatio-temporal autocorrelation methods can efficiently mine the spatio-temporal association patterns of county potential, and can better reveal the complicated spatio-temporal interaction between counties than ESDA methods.  相似文献   

9.
黄河源区径流对气候变化的响应及未来趋势(英文)   总被引:3,自引:1,他引:3  
This study examines the hydrological and meteorological data of the source region of the Yellow River from 1956 to 2010 and future climate scenarios from regional climate model (PRECIS) during 2010-2020. Through analyzing the flow variations and revealing the climate causes, it predicts the variation trend for future flows. It is found that the annual mean flow showed a decreasing trend in recent 50 years in the source region of the Yellow River with quasi-periods of 5a, 8a, 15a, 22a and 42a; the weakened South China Sea summer monsoon induced precipitation decrease, as well as evaporation increase and frozen soil degeneration in the scenario of global warming are the climate factors, which have caused flow decrease. Based on the regional climate model PRECIS prediction, the flows in the source region of the Yellow River are likely to decrease generally in the next 20 years.  相似文献   

10.
By using the observed monthly mean temperature and humidity datasets of 14 radiosonde stations and monthly mean precipitation data of 83 surface stations from 1979 to 2008 over the Tibetan Plateau(TP),the relationship between the atmospheric water vapor(WV) and precipitation in summer and the precipitation conversion efficiency(PEC) over the TP are analyzed.The results are obtained as follows.(1) The summer WV decreases with increasing altitude,with the largest value area observed in the northeastern part of the TP,and the second largest value area in the southeastern part of the TP,while the northwestern part is the lowest value area.The summer precipitation decreases from southeast to northwest.(2) The summer WV presents two main patterns based on the EOF analysis:the whole region consistent-type and the north-south opposite-type.The north-south opposite-type of the summer WV is similar to the first EOF mode of the summer precipitation and both of their zero lines are located to the north of the Tanggula Mountains.(3) The summer precipitation is more(less) in the southern(northern) TP in the years with the distribution of deficient summer WV in the north while abundant in the south,and vice versa.(4) The PEC over the TP is between 3% and 38% and it has significant spatial difference in summer,which is obviously bigger in the southern TP than that in the northern TP.  相似文献   

11.
王慧  张梅青 《地理科学》2021,41(9):1615-1624
考虑市内交通衔接和乘客出行行为选择,通过加权平均旅行时间、经济潜力和空间自相关分析方法相结合,从不同尺度分析高铁建设对京津冀地区可达性的变化和经济活动空间分布格局的演变。结果表明:① 京津冀地区市域和县域的可达性水平得到明显的改善,形成以京津、京广、京沪方向为轴线向外扩展的不规则环状分布格局,且可达性水平呈现南高、北低的特征。② 高铁对沿线核心城市的经济潜力提升作用明显高于边缘城市,呈现出由中心向外圈层式递减,且以北京为顶点的“倒V”的空间格局。③ 随着可达性时间范围的扩大,京津冀区县的经济活动的空间集聚逐渐弱化,且最优辐射范围在3.5 h以内。  相似文献   

12.
电子信息产业是我国国民经济的战略性、基础性和先导性支柱产业。在京津冀区域经济一体化已经上升为国家战略的背景下,探讨京津冀电子信息产业合作与转移问题具有重要意义。首先,从发展水平、优势领域、目标差异、存在问题和空间布局5方面对京津冀电子信息产业发展现状进行了评估;其次,构建了科研支撑基础上、政府主导与引导下的企业主体和行业协会协调的京津冀电子信息产业竞合模式;最后,从环首都经济圈内的"同城"转移、区域电子信息产业的显性转移和隐性转移三方面分析了京津冀电子信息产业的转移与承接路径。研究表明:京津冀电子信息产业在现有优势领域和未来发展目标方面存在显著梯度差,且三方都已表现出较为强烈的合作意愿,从而使合作成为可能;京津冀电子信息产业仍处于国际产业价值链的中低端,发展中存在的问题很多具有共性,因此近期产业布局仍将以本地为主,竞争大于合作;河北承接京津电子信息产业转移不均衡,近期主要以北京为主,天津幅度较小。  相似文献   

13.
鲁西北平原夏玉米产量与土壤硝态氮淋失   总被引:7,自引:0,他引:7  
供水量和氮肥施用量是影响农田硝态氮淋失的主要因素。本文通过田间小区试验,研究了水分和氮肥用量对夏玉米产量和土壤硝态氮的影响。试验表明,高水处理(0~50cm平均含水量控制在85%FC,FC为田间持水量032)和低水处理(0~50cm平均含水量控制在70%FC)间产量差异不显著,施肥量(0、100、200、和300kgNha-1)则具有显著影响,并且在200kgNha-1左右时达到最高产量;高水条件下土壤水分硝态氮下渗强,运移深度大,所有施肥处理在200cm处的土壤水硝态氮浓度都要高于国家饮用地下水标准10mgNL-1;低水条件下水分下渗弱,运移深度小于高水处理,但是在200cm处,200、300kgNha-1处理的土壤溶液硝态氮浓度依然高于10mgNL-1。  相似文献   

14.
京津冀地区产业结构和竞争力空间分异研究   总被引:1,自引:0,他引:1  
对Boarnet公式的经济权重进行修正,以经济增长变化对区域增长的贡献率代替绝对量值的变化,作为区域内经济空间增长的联系强度,并将其作为偏离-份额分析空间模型的空间权重。根据偏离-份额分析空间模型计算三次产业在2002—2005年和2006—2009年2个时段的要素量值变化,用ArcGIS 9.3分析产业结构、产业竞争力的空间变化特征。结构上看,京津冀地区第一产业结构偏强,第二、三产业处于偏弱的态势;竞争力上看,京津冀地区第二产业竞争力呈现整体水平提升,第一、三产业竞争力呈现出多样化的态势。今后应继续保持对第一产业的结构调整力度,快速实现二、三产业结构效率的提升。加大投资和科技投入,保持第二产业竞争实力,逐步实现第一、三产业竞争力的整体提升。  相似文献   

15.
为了厘清京津冀地区污染变化与趋势以及污染与经济发展的关系,为环境污染协同防治、环境与经济协调发展提供科学参考,借助趋势检验模型定性定量分析2000—2013年京津冀主要污染物排放变化趋势,探讨工业细分行业污染排放的结构特征。研究发现:京津冀地区环境污染排放趋势逐渐分化,化学需氧量、烟(粉)尘排放显著减少,二氧化硫排放减少趋势不太显著,废水排放显著增加,氨氮排放减少趋势不显著;京津冀地区污染排放与经济波动、结构调整存在密切联系;从工业细分行业来看,黑色金属冶炼和压延加工业、电力/热力生产和供应业、化学原料和化学制品制造业、造纸和纸制品业、农副食品加工业对污染排放贡献较大。  相似文献   

16.
根据Aqua MODIS 2级云产品和Cloudsat的2级产品资料,结合降水数据和MODIS L1B级辐射率数据,对发生在京津冀地区夏季的三次强降水过程中冰云的宏微观物理量的特征进行分析,并探究这些物理量和降水强度的关系。结果表明:在水平分布中,强降水过程中降水强度高值区内云相为冰云,冰云云顶高度在8~17 km,冰云粒子有效半径、冰云光学厚度、冰水路径分别最高可达60 μm、 150、 5 000 g?m-2;冰云光学厚度、冰水路径、冰云云顶高度随降水强度增大而增大。在垂直分布中,冰云主要分布在3.5 km以上,发生强降水站点的冰云为深对流云,冰云粒子有效半径、冰水含量、冰云粒子数浓度分别最高可达150 μm、 3 000 mg?m-3 、 500 L-1;冰云粒子有效半径高值区存在于云层中下部,且随高度上升而减小,冰云粒子数浓度高值区存在于云层中上部,且随高度上升而增加,冰水含量高值区则存在于云层中部;冰云粒子有效半径、冰水含量、冰云粒子数浓度在9 km以上随降水强度增大而增大。  相似文献   

17.
18.
银行业结构与经济增长之间的关系是经济学界较为关注的问题,尤其是中国的银行业结构与快速发展的中国经济之间的微妙关系更为国内经济学家所关注。选取中国经济较为发达的京津冀经济圈和长三角经济圈作为研究样本,把银行业结构变量引入通常的经济增长模型,采用1987—2007年的面板数据对我国京津冀经济圈和长三角经济圈的银行业结构与经济增长的关系进行了对比分析。结果表明,与长三角经济圈相比,京津冀经济圈银行业集中度的降低将对经济增长更为有利,降低京津冀经济圈银行集中度将会给该地区的经济增长带来新的动力。最后,提出优化京津冀经济圈银行业结构的建议。  相似文献   

19.
Beijing, Tianjin and Hebei each contributed to the comprehensive governance of bulk coal to treat bulk coal pollution in a mutually beneficial way in 2017. The cooperative game theory is used in this paper to study the environmental benefits and cost effectiveness brought about by this comprehensive governance strategy, primarily focusing on the issue of how to maximize the environmental benefits by choosing an appropriate strategy since the benefits to Beijing, Tianjin and Hebei are closely related. Therefore, the linear optimization, game theory and Shapley value method in the cooperative game model are used to find the ways to minimize the total governance cost of bulk coal in the three areas. In addition, the issues of how to carry out rational distribution and transfer of governance capital among the three places are explored according to the actual amounts of consumption of bulk coal, the influence of the coal burning on the PM2.5 and the actual cost of coal governance in Beijing, Tianjin and Hebei in 2017. The results show that the governance task in Hebei Province is the most onerous, and requires more investment than the other two cities. Thus, it requires the support from other two cities, with the amount of increased capital required of about 600 million Yuan. At the same time, the cost saved after optimization in Tianjin is calculated to be the largest, which thus can be adjusted appropriately and allocated to Hebei for the governance of bulk coal. The model constructed in this paper can not only be used to solve the issues related to bulk coal consumption in Beijing, Tianjin and Hebei, but also to carry out the effective distribution of capital, by which a win-win scenario among the three places can be achieved.  相似文献   

20.
杨振山  杨航  孙东琪 《地理科学》2021,41(9):1515-1524
构建了基于系统动力学的城市可持续性动态评估模型,以京津冀地区13个城市为例,评价与模拟2005—2035年各城市可持续发展水平的时空变化趋势。研究结果表明:① 由于资源禀赋和发展路径依赖,不同城市在子系统中的可持续性表现各异,各城市子系统间的可持续性也存在复杂、多样的交互关系;② 近年来京津冀地区各城市综合可持续性呈现出波动上升的趋势,以历史轨迹和当前的区域发展目标来看,未来地区整体可持续发展水平将大幅提高,但北京与其他城市的综合可持续性之间的断层客观存在,且将长期维持。  相似文献   

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