天文辐射、干洁大气总辐射和湿洁大气总辐射是太阳辐射模拟的3种重要起始数据。依托Iqbal Model C和起伏地形下干/湿洁大气总辐射模型,实现了水平面和起伏地形下干/湿洁大气总辐射分布式模拟。以DEM数据作为地形的综合反映,结合常规气象资料,计算了水平面和起伏地形下中国1 km×1 km分辨率日天文辐射量、干洁大气总辐射量、湿洁大气总辐射量的空间分布,并对3种太阳辐射起始数据的时空分布特征做了对比分析。结果表明：3种辐射量均遵循随纬向变化的宏观分布规律;水平面干/湿洁大气总辐射量的分布体现了海拔的影响,水平面湿洁大气总辐射量的分布还体现了水汽分布的影响;起伏地形下的3种辐射量能很好的体现坡度、坡向和地形之间相互遮蔽等局部地形特征对辐射量的影响;以干/湿洁大气总辐射作为起始数据,将有助于提高太阳总辐射的模拟精度。
Extraterrestrial solar radiation (ESR), Global solar radiation under dry clean air (GSRD) and wet clean air (GSRW) are three kinds of important initial data for global solar radiation simulation. Based on Iqbal Model C and model of GSRD and GSRW over rugged terrain, distributed simulation of GSRD and GSRW over horizontal plane and rugged terrain were achieved. Using DEM data as the general characterization of terrain, combined with meteorological data, the daily ESR, GSRD and GSRW with a resolution of 1 km×1 km over horizontal plane and rugged terrain of China were calculated. Furthermore, the spatio-temporal distribution characteristics of these three kinds of radiation were analyzed. Results suggest that: three kinds of solar radiation all have a progressive decrease trend from south to north in China. The distributions of GSRD and GSRW over horizontal plane reflect the influence of altitude, the distribution of GSRW reflects the influence of water vapor. Three kinds of solar radiation over rugged terrain reflect the influence to solar radiation by the topographical factors such as slope, aspect and terrain inter-shielding. To use GSRD and GSRW as the initial data will help to improve the simulation precision of global solar radiation simulation.
作为东北亚重要的国际性河流,图们江实现国际通航,对图们江地区国际合作开发具有重要意义。在梳理图们江国际通航的理论依据基础上,运用转化博弈思维与方法,建立博弈模型,对图们江国际通航合作中的问题与出路进行了探讨。结果表明:① 图们江国际通航受阻是俄朝寻求相对利益最大化的理性反应,而俄朝之所以采取非合作策略,其深层根源是地缘政治优先与战略均衡思维及其之上的多维利益考量,以及法理性制约;② 在图们江通航问题上的非合作博弈的现实,最终导致了中俄朝3个沿岸国的绝对收益最差、群体收益也最小,陷入与社会期望完全相悖的社会两难境地。③ 结成合作大联盟是图们江通航博弈的帕累托最优,这必将为联盟群体带来最大化效率,其成员的效率也是最大的;④ 联盟结构与联盟成员的目标取向与实现路径正好相反,而个体收益水平与合作策略的选择之间也非简单线性相关,这就导致大联盟结构必然是非稳定的;⑤ 由于缺乏结成大联盟的内生动力与自我强化机制,必须借助外部强制力,诸如具有强制约束力的法律和转移支付手段等,建立起合作博弈的社会机制体系,才能确保其稳定性。
As an important international river of the Northeast Asia, the Tumen River directly adjoins with three countries China, Russia, and Korea by the channel. In the east, it is close to Japan and South Korea across the sea, and to the west of it can be migrated to attract Mongolia through the land bridge. It has a signification of the Tumen River cooperative development that the Tumen River to come true international navigation. Based on the Tumen River international navigation theoretical basis, which illustrated the realization of the Tumen River international navigation basis, historical basis, and legal basis, this paper established a basis of the Tumen River international navigation game theory model and the cooperative game alliance structure. Through the reasonable hypothesis and simplification science, this article will deal with it quantitative qualitative problems, and try to discuss and slove the problems of the Tumen River international navigation, using the transformation game view and methods. The results show that: 1) It is the rational reaction of the most profitable trail to take between Russia and Korea, why is the Tumen River cannot navigate to the sea. The deep root that Russia and Korea take "no-cooperation" strategy is multidimensional interest considerations through geopolitical priority and strategic equilibrium, mainly including the impact of geopolitical relations, multidimensional distribution pattern of the rights and interests, regional international cooperation level of restriction, the regulation of international law, the constraints of resources and environment, and so on multiple factors. 2) the Tumen River navigation obstruction is the results of non-cooperative game strategy adopted by Russia and Korea. However, the situation of non-cooperative is not accord with the social expectation of common development, mutual reciprocity and mutual benefit to China, Russia, and Korea, and it does not comply with a long-term traditional national relationship what the three countries pursuit of “friendly cooperation and coordination” with solemn promise, also does not assort with the international cooperation function of the Tumen River area′s development and opening up. What′s more, it deviates from the usual practice and trend of full development and utilization in the international rivers. 3) Russia, China, and Korea should form a grand coalition to work for the Pareto optimum of the Tumen River international navigation in conflicts around nations. This will bring for not only grand coalition but also its members to maximize efficiency. 4) Goal orientation of the grand coalition structure and its member is exactly opposite to the realization route, and the choice between individual income level and cooperation strategy is not simple linear correlation. So the grand coalition structure is inevitable instable. 5) Due to the lack of endogenous power and self strengthening mechanism about grand coalition, it is important to have the aid of external coercive power such as forced binding law and transfer payment methods, and set up cooperative game social mechanism system in order to ensure its stability. As a response, a cooperative game mechanism of social system should be designed, which is composed of friendly understanding mechanism, the side payment mechanism, institutional mechanism, diplomatic negotiation mechanism, and the internationalization of mechanism.
基于城市-区域系统模型,从“三化”的内在机理出发,提出了“三化”协调发展的“三位一体”社会工程系统模式。结合中原经济区“三化”协调的国家战略要求,分析了中原经济区“三化”协调发展的现状与问题,并通过整体协调评价、城镇化与工业化、产业结构三者对比模式、城乡协调度3个方面对中原经济区“三化”协调发展的实际情况进行定量分析,结果表明：① 在城镇化的快速推进和农业现代化水平不断提高的同时,工业化水平提升的空间不足。② 城镇化水平仍严重滞后于同期的工业化水平和产业结构比重。③ 城乡协调发展水平整体上呈现波动上升趋势,2001~2004年间与河南省的城乡协调发展差距较大,到2005年之后城乡协调发展水平才持续平稳上升。
New industrialization, new urbanization and agricultural modernization are the three strategies of modernization construction in the 21st century in China, the coordination development of which will effectively promote the process of national modernization and regional coordination development. The supporting guidance of state council of China on the speeding up constructing the Zhongyuan economic region of Henan Province is issued on September 29th, 2011, which marks the rise of official national strategy of Zhongyuan economic region. In state guidance, the way of actively exploring the coordination development of industrialization, urbanization and agricultural modernization (IUAM for short) will be not done at the expense of agriculture and food, while ecology and the environment is the key construction task. How to make the coordination of the three-process is an important proposition, so we give a theory for explaining IUAM coordination development based on urban-regional system model. According to internal mechanism, interactive principal of urban-regional system, this article proposes a trinity social engineering system model of IUAM coordination development. It gave a basic analysis on industrialization, urbanization and agricultural modernization from the national strategy requirement, and makes a quantitative analysis on IUAM coordination development process through overall coordination evaluation model, urbanization comparative analysis model and urban-rural coordination development model. The results show that the industrialization contributes to economic development weakly, the urbanization level lags the industrialization level and industry structure in the same period, and the urban-rural relation is in an unstable fluctuating status.
制度转型和城市空间重构背景下,中国城市居住和就业空间结构发生着巨大的变化,职住关系变化产生的职住分离及其引发的交通、环境问题逐渐受到重视。基于2005年、2010年两次大规模问卷调查数据,运用多元统计和空间探索分析方法对北京市城市居民通勤满意度的社会属性差异和空间分异进行了实证分析。研究发现：① 2010年北京市居民通勤满意度总体较为满意,但与2005年相比,通勤满意度有所下降。② 不同人群的通勤满意度差别明显。其中,一般平民和年轻打工族的通勤满意度相对较高,但年轻打工族对通勤不清楚或不关注的比例相对略高;而高收入阶层和年轻白领的通勤满意度相对较低。③ 通勤满意度的空间差异显著。通勤满意度较高的“热点区”主要集聚在内城、南城区域的个别街道,满意度较低的“冷点区”主要分布在城市远郊边缘街道;但在不同区域也零星存在通勤满意度得分的异质区域。
With the reform and opening up, China experienced a rapid growth during the past 30 years. At the same time, the urbanization level increased to nearly 50% at 2010. The transformation in China had provided a great opportunity for theoretical work on the urban study. The urban spatial structure had undergone tremendous change with housing reform too. The traffic problems such as longtime commute, traffic congestion and air pollutions that accompanied with the home-work separation are paid more attention now. Beijing, as the capital of China, is also faced these challenges. In this article, an empirical analysis focused on the difference of residents′ commuting satisfaction in Beijing was done based on the large-scale survey data both in 2005 and 2010. The survey focused on the commute behaviors and the social-economic characteristics of the people worked in Beijing. We find out that the people can be divided into 4 groups by using Principal Component Analysis based on their socio-economic characteristics. The 4 groups are civilians in general, young migrant workers, high-income group and young white-collar workers. And then the spatial distribution of the 4 groups was tested by using Moran′s I. The results show that there are significant spatial autocorrelation in distribution of civilians in general and young white-collar workers. But the distribution of young migrant workers and high-income group are more random than spatial cluster. The hot spots of the cluster of the groups were found by LISA. General civilians mainly gather in western suburbs and young migrant workers mainly in urban central area or nearby Zhongguancun; high-income group also gather in urban center while young white-collars cluster are located in northern area of the city and the area near the East Fifth Ring Road. The difference of the commuting satisfaction among these groups is tested too. The results show that compared with 2005, the residents commute satisfaction has declined in Beijing in 2010. One reason may be the commuting time increased from 38.0 min to 43.6 min at the same time. The commuting satisfaction of civilians in general and young migrant workers is relatively higher while high-income group and young white-collar workers had lower satisfaction. The result shows that there is significant spatial difference of the residents’ commuting satisfaction too. The hot spot with higher satisfaction clustered in the center area of the city, and the cool spot with lower satisfaction clustered in the suburbs area of the city. The spatial distribution of the groups can help to understand the pattern of the residents’ commuting satisfaction.
The spatial choice of the employment transference of the rural labors is influenced not only by the economic utility factors but also by the individual subjective cognition. This article, from the microcosmic perspective of rural labor force, discusses the process of this spatial decision and its internal relationship and reveals its spatial decision-making mechanism through the path analysis of transferring employment motivation, environment cognition and decision methods. The spatial choice process of rural labor’s employment transference is divided into three stages: motive produce, environmental cognitive and decision-making forms. The case study of Hefei City shows: the motives of the rural labor force’s employment have been transferred from seeking pure income to pursuing comprehensive development. The rural labor forces think that Hefei is a city with fast economic development, good education and science and technology development and good transportation business facilities, close to their homes, and its environment is easy to adapt to, but its most labor intensity is big, and the income is low. The initiative of rural labor’s employment transference decision has surpassed the passivity. This study creates a causal relationship model among employment motives, environment cognition and the way of decision to better help understand the psychological process of the rural labor’s decisions of employment transference. The case study shows: firstly, the clearer the rural labor’s transferring employment motivation, the clearer their cognition of the significant positive influence on the environment, which improves the rural labor force’s expectations to transfer their employment and to resident in the city and helps them make better employment transference; secondly, while other influences of environmental cognition on decision-making method are not significant, the distance of employment has significant positive impact on decision-making, and the image of employment place has negative influence on decision-making, which shows that the decision’s initiative is influenced more directly by such factors as distance and image; and therefore, to improve the construction of the city where rural labor force have crowded in and to improve the urban employment image will help effectively transfer the rural labor force. The main disadvantages of this study are: the concepts and effective measurement about the environment cognition and decision mode still need more theoretical support and future’s further proof, and the only one-way causal relationship from motivation to environment cognitive and to decision has been validated while other relationships still need to be further validated.
Residents' perceptions and attitudes is the most intuitive evaluation of tourism development, there will be differences in perceptions and attitudes of residents due to heterogeneity factors. Existing research results show that, the distance factor is an important explanatory variable causing differences of the residents' perceptions and attitudes within the larger spatial scales. In order to study on the heterogeneity of factors causing the differences of residents' perceptions and attitudes in the small scale spatial, this article adopts a case study of the four communities adjacent to Huangshan Scenic Spot for empirical research: Through questionnaire surveys and in-depth interviews, it is found that there are certain differences in the perception of the tourism economy, living environment and social and cultural positive and negative effects of community residents in tourism development. From the aspects of the location, community and scenic spot, it is found that the relative location, community organizations involved in resource development of the scenic spot and the ability to coordinate the distribution of benefits, as well as governance mode changes of scenic spot are combinative effecting the tourism development of adjacent community and community benefits which are resulting in the differences of residents' perceptions and attitudes towards tourism. The research findings show that relative to extrinsic factors as the geographic conditions and scenic spot governance mode, the community need to give full play to the dynamic role of community organizations in community, to promot coordinate development of communities and scenic spot.
依据房价网和搜狐焦点长春地产等网络数据,借助反权重分析方法及GIS技术平台,对1991~2011年长春市新建的住宅分布格局进行分析,得出长春市住宅空间分布特征：① 住宅的郊区化趋势日趋明显;② 住宅沿城市主干道轴向布局和以城市绿地及水面为中心环状布局特征鲜明;③ 住宅价格总体上呈单中心多极核圈层分布;④ 价格重心相对于城市原有的几何中心南移等。同时,在对新建住宅空间布局的影响因素进行分析的基础上,进一步分析了这种空间布局的效应：城市人口空间分布的郊区化、职住分离加剧、城市交通压力的增加以及城市商业空间的郊区化和多中心化。
This article, taking the urban area of Changchun as an example, based on data from the websites of Sohu Focus-Changchun Real Estate and www.fangjia.com, applies counter weight analysis and the GIS platform. It analyzes the distribution patterns of newly-constructed residential space in Changchun from 1991 to 2012, and points out that the residential pattern of space in Changchun has the following features: 1) an evident tendency of housing suburbanization; 2) residential space distributes along the city’s main roads in an axial arrangement and centers on urban green space and water space in a circular arrangement; 3) housing prices show general single-center and multi-core circular distributions. Further, on the basis of analyzing the factors that influence newly-constructed residences, the article analyzes the effect of this kind of space distribution: the separation of housing and workplaces, resulting from the suburbanized distribution of the city’s population, is aggravating traffic pressures and the suburbanization and multi-centralizaton of business spaces.
The Taosi site is located at Xiangfen County, Linfen City, Shanxi Province. Linfen area is one of the important civilization cradles in China,in which the cultures of Yangshao and Longshan periods developped continuously. The Taosi site is a large settlement of the Taosi culture in Longshan period, and it has some characteristics of an early capital city. This article explores how the cultural and environmental backgrounds effect formation of the Taosi capital city. The investigation focuses on analyses of the distribution features of the Taosi culture sites using Geographic Information System, pollen assemblage from a loess-paleosol sequence, data collected from geomorphologic survey and archaeology materials. The archaeological sites of the Taosi culture are classified into five grades, and the Taosi site is the largest. The analysis of GIS shows that the sites of the Taosi culture can be divided into eight interconnected settlements. The Fenhe River passes through Xiangfen interconnected settlement, which has the highest site density. The archaeology materials show that, there are a few of pottery kilns and stone artifact workshops in the Taosi site. A large number of charred plant seeds are identified from the Taosi site, such as foxtail millet(Setaria italica) and broomcorn millet(Panicum miliaceum). The pollen analysis shows that, from the late Last Glacial to middle Holocene, Pinus, Artemisia, Selaginella sinensis and Concentricystes are the main elements, among which Pinus and Concentricystes increase sharply. The result of geomorphologic survey shows that, the terrain is flat, with a stable water supply from Taer Hill, before the building of the Taosi site. Four major influencing factors in the formation of the Taosi capital city are concluded as follow. First, the continuous development of regional culture under the suitable environment of the Holocene optimum, and the diversity of the Taosi culture promote a flourishing culture. Second, the development of settlements is conducive to the agglomeration of population and resources, and as a result, a central settlement forms. Third, the geographical conditions of the Taosi site are able to meet the needs of a large numbers of people for food and energy. Finally, flat land with rills, abundant building materials, developed handicrafts and convenient traffic conditions are conducive to the building and development of a capital city.
Based on statistical data of inbound tourism and sampling information of inbound tourists from 1997 to 2010 provided by National Tourism Administration of China, using models such as transfer-quantity of inbound tourists, spatial concentrated index and transfer matrix of inbound tourist flows, the inbound tourists flows distribution evolution process of Shanxi, Henan, Hubei, Hunan, Anhui, Jiangxi provinces is analyzed spatially and temporally. The results show that: the inbound tourists concentration and diffusion index are fluctuated evolution tendency in six provinces of central China. From the view of the inbound tourists concentration ability and external dependence, Jiangxi Province enjoys the highest capability, followed by Henan, Shanxi, Hubei, Anhui and Hunan by turn. For the inbound tourists diffusion ability and external dependence, Anhui enjoys the highest capability, followed by Shanxi, Jiangxi, Hunan, Hubei and Henan by turn. The six provinces of central China are still the secondary destinations of the inbound tourism of Beijing, Shanghai, and Guangdong spreading; Beijing, Shanghai and Guangdong are the secondary destinations of inbound tourism concentration in the six provinces of central China. The inbound tourists flow from east to west, and there exists the inbound tourists concentration and diffusion among the six provinces of central China, where the tourism resources and the distance attenuation still play a role on the inbound tourists flow. The inbound tourism flows concentration source and diffusion destination in the six provinces of central China has significantly interactive.
Climate change characterized by global warming has become one of the world′s most important environmental issues. Its impact on hydrology and water resources has attracted more and more concern from international scholars. This article briefly reviews the development of studies for impact of climate change on hydrology and water resources, and then focuses on the key fields in the studies: analysis of variation trends in runoff and related driving forces, quantitative assessment for climate change and human activities impact on water resources, watershed modeling to assess impact of potential climate change on hydrology and water resources, study of extreme hydrologic events under climate change scenarios, and adaptation strategy for climate change impact on water resources. It also introduces the important techniques in the related studies, including hydrologic simulation, future climate change scenarios, and connection of hydrological model with climatic model. Finally, it raises problems and weakness in study and puts forward some suggestions, including development trends of future research and key problems to be solved.
选用11种概率分布函数和单参数二维阿基米德族Copula函数,系统分析了塔里木河流域（简称塔河流域）8个水文站最小连续7日平均流量。研究结果表明：① 韦克比函数最适合描述塔河流域枯水径流的概率特征;② 1987年以后重现期较短的干旱发生频率降低,而重现期较长的干旱事件发生概率增加,主要是由于气候的季节变化及各河流流量的补给类型不同,从而对塔河枯水流量有一定影响;一般来讲,春季气温对枯水的影响要大于降水变化对枯水的影响;③ 叶尔羌河、阿克苏河等流域水文干旱联合重现期和同现期变化基本一致;开都河流域发生干旱概率要小于叶尔羌河和阿克苏两流域,而开都河流域同时发生干旱的概率大于叶尔羌河和阿克苏河,3个流域重现期短的干旱遭遇概率较大。研究表明,气候变化并没有从根本上改变新疆旱灾情况,同时,由于耕地面积、人口等的增长,水资源需求量增加,在水资源供需方面仍存在非常尖锐的矛盾。
In this article, 11 probability distribution functions and two dimensional Archimedes Copula function are adopted to systematically analyze the probability behaviors of the 7-day low flow regimes (the minimum average flow for the consecutive 7 days) at eight hydrological stations located in the Tarim River Basin. The L-moment technique is used to estimate the parameters of the probability functions and the Kolmogorov-Smirnov method (K-S) is accepted to evaluate the goodness-of-fit of the probability functions. Possible causes and implications of low flow changes are analysis. The results show that: 1) Wake distribution is the candidate distribution function with the highest goodness-of-fit in the study of the extreme flow regimes over the Poyang Lake basin; 2) Climate changes after 1987 has reduced the frequency of drought of low return period. While Climate changes after 1987 has not reduced the frequency of drought of high return period in some stations, which is caused by climate seasonal changes and type of river supplies. Moreover, the temperature impact of low flow is greater than the rain in the spring. 3) The changes of joint return period and return period in the Aksu River are same with the changes in the Yarkand River. However, drought frequency in the Kaidu River is less than the Aksu River and the Yarkand River. While frequency of drought occurred in the same time in tributary of the Kaidu River is more than the Aksu River and the Yarkand River. Because the population and cultivate areas increase fast, climate change have not basically changed the drought in the Tarim River Basin.
利用丹东1951~2010年逐日温度和降水资料,以多重分形去趋势波动分析法定义极端事件的阈值,分析了该地区极端最高温度、极端最低温度和极端降水的变化特征。结果表明：近60 a丹东极端最低温度事件比极端最高温度和极端降水事件发生次数多,极端最高温度强度比极端最低温度大,平均超出了1.5 ℃,而极端降水平均强度为30.3 mm,都在20世纪70年代最小,70年代是转折期;50年代的极端气候事件（温度和降水）最为严重,其次是90年代,70年代的严重度最轻;极端降水频次变化不明显,极端最高温度事件可以由夏季平均最高温度的变化预测,有不显著的增多趋势,而极端最低温度事件可以用冬季平均日较差温度的变化预测,在今后一段时间内有显著减少的趋势。
Based on the daily temperature and precipitation in Dandong during 1951-2010 and the definition of the threshold of extreme events using the multifractal detrended fluctuation analysis, this study analyzes the characteristics of extreme maximum temperature, extreme minimum temperature and extreme precipitation. The results show that the frequency of extreme minimum temperature event is more than that of extreme maximum temperature and extreme precipitation events over Dandong in recent six decades. The intensity of extreme maximum temperature is larger than that of extreme minimum temperature, with the average value of 1.5 °C. The average intensity of extreme precipitation is 30.3 mm. Both the frequency and intensity of these extreme events are the smallest in 1970s, which is also the turning point. The extreme climate events (temperature and precipitation) in 1950s are the severest, and these events in 1990s are the second severest, whereas the severity of these events in 1970s is the smallest. Meanwhile, the frequency of extreme precipitation varies unobviously. The frequency of extreme maximum temperature event could be predicted by the changes in the average summer maximum temperature, which shows that there is insignificant positive trend in extreme maximum temperature. The frequency of extreme minimum temperature can be forecasted using the average winter daily temperature range, which results in the significant negative trend in the frequency of extreme minimum temperature in future.
通过在粤北石漠化地区选取不同石漠化阶段样地,进行人工降雨模拟试验,研究粤北石漠化地区水文过程。结果表明：随石漠化程度的加深,地表植物对雨水最大截留量不断下降,其中以重度→极重度阶段降幅最大,达6倍多。土壤持水量在重度→极重度石漠化阶段发生转折。地表径流在中度和重度石漠化土地上具有相同特征,但在与轻度和极重度石漠化土地中差异明显。当雨强为30~50 mm/h时,产流35 min内总径流量以中度石漠化样地最高;当雨强为51~60 mm/h时,以极重度石漠化样地最高;而当雨强为61~70 mm/h时,则以重度石漠化样地最高。在各石漠化阶段样地上以雨强35 mm/h进行人工模拟降雨60 min,有0.6%~2.71%雨水被植被及枯落物截留;2%~53.31%雨水被土壤吸收;2.18%~7.37%雨水转化为地表径流;41.8%~93.41%雨水渗漏形成地下水。
Some plots with different stages of rock desertification were selected in rocky desertification area of northern Guangdong to study the hydrological process of there through artificial simulation rainfall test. The results show that: the maximum ground surface vegetation interception of rainfall is decreasing with the deepening of rock desertification, and the maximum decreasing range appears in severely stage to very severely stage which is more than six times. Soil moisture capacity is turning from severely stage to very severely stage. The surface runoff appears same characters in moderately and severely rocky desertified land, but has obviously difference in slightly and very severely rocky desertified land. When rainfall intensity is 30-50 mm/h, the highest total runoff of runoff yield for 35 min is in moderately rocky desertified land. When rainfall intensity is 51~60 mm/h, the highest total runoff of runoff yield for 35 min is in very severely rocky desertified land. When rainfall intensity is 51~60 mm/h, the highest total runoff of runoff yield for 35 min is in severely rocky desertified land. After artificial simulation rainfall with 35 mm/h rainfall intensity in plots with different stages of rock desertification for 60 minutes, 0.6% to 2.71% rainwater is intercepted by vegetation and litter, 2% to 53.31% rainwater is absorbed by soil, 2.18% to 7.37% rainwater has transformed to surface runoff , 41.8%~93.41% rainwater has leaked and formed groundwater.
基于遥感数据和改进的双重指数法,从裸土面积、裸露强度和破碎度三方面研究了福建省长汀县1988~2010年的地表裸土时空变化。研究表明,该县近22 a的水土流失治理已大大减轻了地表的裸露程度,地表裸土面积从175.5 km2减少到86.6 km2;地表裸露强度从0.487下降到0.383; 裸土破碎度从0.103上升到0.207。在1988~1999年和1999~2010年的2个时间段里,裸土面积的变化呈现逐渐减少,减速加快的趋势,客观地反映了长汀县水土流失治理的重要扶持政策所产生的积极效应。
Changting County of Fujian Province is one of the most typical reddish soil loss regions in southern China. Serious soil erosion has resulted in environmental and ecosystem degradation in the county. Local people and governments have been struggling for the control of the soil loss for more than two decades. To investigate and assess the changes after the effort, this study used remote sensing technology to analyze spatiotemporal dynamics of the soil exposure degree in the county during the period from 1988 to 2010. The bare soil features were estimated from the Landsat TM/ETM+ images of 1988, 1999, 2004 and 2010 based on two thematic indices-normalized difference soil index (NDSI) and normalized difference impervious surface index (NDISI). The used four images were geometrically corrected and registered to allow spatial overlay analysis between images. After the geometrical correction, the digital number (DN) values of the images were converted to at-satellite reflectance. The NDSI was used to enhance and extract soil features from the four used images with proper threshold values. However, the extracted soil features were found to have been mixed with built-up land features due largely to the spectral confusion between the two categories and the similar result in the NDSI performance. In order to improve the accuracy of the extracted soil feature, the NDISI was further used to filter out the unwanted built-up land features from the extracted soil features using a logical tree algorithm, as the NDISI is the index specially designed for the highlight of impervious surface features represented mainly by built-up lands. This significantly improved the estimate of bare soil and the extraction accuracy can reach up to 95.95%. Based on the extracted bare soil features, the exposure degree of bare soil and spatial and temporal changes of bare soil were analyzed. Results showed that the 22-year fight for treating soil loss has greatly reduced exposed bare soils in Changting County. The area of bare soil has been greatly reduced from 175.5 km2 in 1988 to 85.6 km2 in 2010, bare-soil exposure intensity dropped down from 0.487 to 0.383, and fragmentation degree of bares soil increased from 0.103 to 0.207. In the two observed periods (1988-1999 and 1999-2010), the decrease in bare soil area was in an accelerate speed, which was -3.74 km2 per year during the 1988-1999 period and -4.34 km2 per year in the duration between 1999 and 2010. This corresponds closely to the two major policies issued by the Fujiang Provincial Govenment specially for the county’s soil loss treatment. Obviously, government policies accompanied with effective actions were the major driving forces to the reduction of the exposure degree of bare soil in the county during the study period.
Because of the special terrain features in Karst peak and cluster depression of Karst mountainous areas, matter and energy cycle and natural environment are close. This also led to a vulnerable ecological environment in this area. In addition, it is an underdeveloped area in economy; livelihood mainly relies on traditional planting in the rural, so the agricultural production activities have an important influence on the regional ecological environment and landscape. Thus, Discussions on the agricultural production activities and its ecological effect will helps to reveal the effect of agricultural production activities acts on regional ecological environment and landscape. Further, the discussions will helps to ecological environment recover in Karst peak and cluster depression areas. This article aims to reveal the effect of agricultural production activities acts on landscape pattern in Karst peak and cluster depression areas. In order to achieve this goal, the effects of agricultural production activities influence of hydrological system, vegetation system, and soil system in Karst peak cluster depression system were studied, by means of field investigation and relevant literature sorting. The results show that in karst peak cluster depression area, the relationship between agricultural production activities and landscape change is obvious. The mechanism of agricultural production activities acts on landscape pattern mainly through blocked epikarst water cycle path by the means of original vegetation destruction changed the surface karst water cycle paths and the epikarst runoff model. These eventually lead to stability loosening of the peak cluster depression vegetation system, and systematic destruction of landscape. More ever, these will lead to the fragmentation of landscape, decreasing the heterogeneity and stability of landscape, causing the landscape reverse succession and even rocky desertification.
In this study, the characteristics of change trends of growing season and their spatial differences among the different indicators over Inner Mongolia were analyzed, using meteorological data recorded in 47 meteorological stations over the year 1961-2010, based on Mann-Kendall trend test and linear regression method. The results showed that the growing season length of Inner Mongolia region increased significantly from 1961 to 2010, about 13.0-17.0 days. The high consistency among different indices meant that thermal growing season can be used as an key application indicators to reflect temperature changes in this region. However, the average growing season trends over the whole region largely covered the spatial differences between the indices. Growing season trends in western and central Inner Mongolia were more sensitive to the temperature threshold. e.g. the start of the growing season of 0℃ threshold shifted relatively earlier, and the length increased strongly in Alxa League, while the increasing end and length was more prominent under 10℃ threshold in Ulanqab and Xilingol League. Including or excluding a frost criterion had a significant impact on the growing season trends in most central parts of Inner Mongolia, especially on the beginning of the growing season.