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  • 2014 Volume 33 Issue 6
    Published: 10 June 2014
      

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  • CHENG Weiming, WANG Jiao, ZHOU Chenghu
    2014, 33(6): 1003-1014. https://doi.org/10.11821/dlyj201406001
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    The study on lunar topography and geomorphology is one of the key tasks of the lunar exploration program, which are essential to expanding understanding of lunar surface. The lunar topography research also had a profound effect on other studies such as the lunar rock formations, the estimation of relative lunar age, the correction of landing sites of detectors, the recovery of the thickness of lunar soil, and the evolution history of the moon. This paper reviewed the research of lunar surface morphology from the following four aspects: (1) the formation and visualization of lunar topography and geomorphology; (2) the macroscopic analysis and quantitative characterization of lunar topography and geomorphology; (3) the detection, classification and spatial analysis of lunar impact craters; (4) the deduction of lunar relative age based on lunar impact craters. Among the above mentioned four aspects, the emphasis was been placed on the research of lunar impact craters. Finally, we discussed the development of lunar topography and geomorphology. In the future, the complete lunar impact crater database, including multi index, such as spatial position, morphology, shape, size and ray etc. will be built; methods on how to distinguish main crater and secondary craters need to be strengthened, and thus an expression paradigm for morphological characteristics of impact craters also need to be built to understand and estimate their evolutionary history. Based on multi-sources RS and DEM data, a topographic regionalization map needs to be finished by means of many topographic index and imagery characteristics. Based on the database, the spatial distribution of lunar crater, the lunar evolution and the study of comparative planetology based on lunar topography and geomorphology will be the hot point to be researched.
  • MENG Zhiguo, PING Jinsong, XU Yi, CHEN Shengbo, CHEN Si
    2014, 33(6): 1015-1022. https://doi.org/10.11821/dlyj201406002
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    The collection of microwave radiometer data (CELMS data) from Chang'E-2 satellite makes it possible to study the influence of the layer thickness on the microwave thermal emission of the lunar regolith. In this paper, the raidative transfer simulation is employed to study the change of the brightness temperature with the lunar regolith layer thickness in different frequency, (FeO + TiO2) abundance and surface temperature. The results indicate that the change of the simulated brightness temperature with the thickness is apparent to certain depth in low frequency and the low (FeO+TiO2) abundance, while the correspondence between the brightness temperature and the thickness is missing if the regolith is thick enough. The influences from the regolith layer thickness is much weaker than that from the frequency, the (FeO+ TiO2) abundance and the surface temperature, which are crucial factors to invert the lunar regolith layer thickness with the CELMS data. Then the influence of the thickness on the microwave thermal emission from the lunar regolith is analyzed with the CLEMS data from Chang'E-2 satellite and the measurements from Apollo projects. The results indicate that correlation between the thickness and the microwave thermal emission of the lunar regolith is weak. The microwave emission of the lunar regolith will be a bit more heavily affected by the regolith layer thickness if the observation is in low frequency, the surface temperature is low and low (FeO+ TiO2) abundance of the regolith is low. Moreover, the simulated brightness temperature agrees well with the observed CELMS data in lunar highlands along the Moon Equator in 3 GHz, while it is much bigger at noon or much smaller at dawn than the observed CELMS data in lunar maria. It is feasible to retrieve the lunar regolith layer thickness in lunar highlands using the CELMS data in 3 GHz on dawn. The research is essential for the inversion of the lunar regolith parameters with the microwave radiometer data from Chang'E satellites.
  • PING Jinsong, SU Xiaoli, HUANG Qian, YAN Jianguo, SHEN Yuling
    2014, 33(6): 1023-1030. https://doi.org/10.11821/dlyj201406003
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    Primary studies were carried out using the new 360 orders and degrees of lunar topography model CLTM-s03 obtained by laser altimetry data of Chang'E-1 lunar orbiter. 3D CCD image data was validated; a constant vertical bias of ~900 m in the CCD DTM was found and corrected track by track. The differences between CCD DTM and CLTM-s03 are close to 2.0 km. The errors are mainly from orbits, angle bias for the CCD camera installing, as well as the image error. To obtain a higher accuracy lunar DTM of 20-30 m at radical direction, advantages of both LAM DEM and CCD DTM are required. The long wavelength parts of DTM are suggested to use the LAM DEM model which may cover 0-360 orders and degrees. The middle and short wavelength parts will use the 3D CCD images, where the long wavelength parts of CCD have been cancelled. Igneous and impacting activity dominates the evolution history of the Moon. By using Chang'E-1 image data, we found several shield volcanoes, including YUTU shield volcano with Marius Hills and the Aristarchus Plateau shield volcano. The classical lunar surface crater density counting method was used to study the age of them based on the validated CCD image data. It is found that the surface impacting age of YUTU shield volcano is about 3.52±0.02Ga. By combining the topography data with the gravity data, it is found that this shield volcanic area has higher crustal density, lower elasticity thickness and remarkable inner magma load. Additionally, we removed the terrestrial gravity constrained by topography from free air gravity, and then obtained the Buguar gravity of the Moon. The high resolution of gravity and topography data help us to find three new mass concentrating areas under the surface of the Moon. The Szilard Crater, one of the new mascons, is located to the northeast of Richardson Crater on the farside of the Moon. The newly identified mascons will benefit the investigation of the lunar igneous evolution.
  • JI Wei, YANG Ruixia, LI Chao, LUO Lei, WANG Xinyuan
    2014, 33(6): 1031-1039. https://doi.org/10.11821/dlyj201406004
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    Since mare is one of the major geographic units of lunar surface, the landscape features of mares can provide a direct reflection of the ups and downs of lunar surface and its geodynamic mechanisms. This paper extracts the scopes of the typical mares with different fill lithology at different latitudes by manual vectorization based on the image of moon and the global lunar DEM model by Chang'E-1. The geomorphological features of mare borders and their terrain surfaces are estimated by using box-counting dimension method, cubic-covering method and q-Dq language of multi-fractal method. The results demonstrate that: (1) The complexity of lunar landscape can be described effectively by fractal methods. The values of fractal dimension of five mares' borders range from 1.065 to 1.100 while the average is 1.086, and the standard deviation is 0.014. The border lines fitted in the double logarithmic coordinates are approximately parallel. (2) The values of fractal dimension of mares' terrain surfaces range from 2.704 to 2.852, and the standard deviation is 0.051. The graph of lnδ-lnN(δ) also shows an approximately parallel pattern, but the dispersion degree is higher than that of the mare borders. (3) The q-Dq graph of multi-fractal analysis of mare landscape indicates an overall trend of non-increase. Although the Dq values reach saturation when q=-10 and q=0, the differences are small. (4) Analysis of the results of line and surface single fractal and multi-fractal dimensions shows that the five mares have their fractal features, while the differences among each other are little. In the view of dynamics, after the formation, the internal forces stopped or become feeble, which can be concluded that their fractal characteristics are almost the same. In addition, external impact of meteorites changed the lunar surface slightly, resulting in the differences on the fractal characteristics.
  • LI Wei, SUN Yiwei, WAN Wenhui, LIU Zhaoqin, HU Wenmin, YUE Zongyu, DI Kaichang, MIAO Yi, ZHAN Lei
    2014, 33(6): 1040-1048. https://doi.org/10.11821/dlyj201406005
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    Chang'E-3 rover is the first lunar rover launched by China National Space Administration. As the‘eyes’of the rover, the navigation cameras play a crucial role in mission operations of the rover on lunar surface. High-resolution DEMs and DOMs generated from navigation images using photogrammetric techniques can provide accurate terrain and location information for rover positioning and route planning. Simulation tests in experimental field before launch are necessary to ensure the effectiveness and reliability of the techniques and procedures. Computer simulation is undoubtedly a low-cost and efficient way to simulate the lunar terrain and environment in the early verification process of the navigation cameras. Using computer simulation, a variety of lunar terrain can be generated easily for verification of the measurements of the navigation cameras with the pre-defined parameters. In this paper, techniques of fine-scale lunar terrain simulation and texture simulation are studied for navigation camera verification. Lunar terrain simulation consists of lunar basic terrain simulation and lunar surface feature simulation. For basic terrain simulation, we first generate a rough terrain using random fractal algorithm, and then get a finer terrain from rough terrain using midpoint displacement method. For lunar surface feature simulation, 3D models of surface features, such as craters and rocks, are generated and placed on the basic terrain according to certain rules, and then they are merged to the terrain by modifying the raster terrain data, so that the terrain data can reflect the changes caused by the added feature models. For texture simulation, texture mapping and texture merging methods are used to generate terrain-consistent texture. Texture mapping creates textures based on the elevation values of each position and its neighbors in the terrain data. Texture merging generates local textures by Gaussian-weighted method using texture samples collected in advance. Lighting illumination is also added to the generated terrain by Open Scene Graph software. Finally, a realistic simulative lunar scene is generated and verification tests of the navigation cameras are performed according to the camera parameters and image acquisition instructions.
  • HE Yanhu, CHEN Xiaohong, LIN Kairong, WU Xiaoqing, LI Yan
    2014, 33(6): 1049-1058. https://doi.org/10.11821/dlyj201406006
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    Based on meteorological and hydrological data such as precipitation, evaporation and runoff in the Dongjiang river basin from 1964 to 2012, using various methods including linear trend estimation, M-K trend test, amplitude of variation and elastic change and combining ArcGIS spatial statistical analysis technology such as autocorrelation, this paper analyzes the spatial and temporal variations of the runoff coefficient for this region and the space corresponding relation between the influencing factors such as rainfall, evaporation and vegetation and the runoff coefficient. The results show that all the annual runoff coefficients are on the rise on the Dongjiang river basin in recent 50 years. Annual average runoff coefficient increases with the increase of watershed spatial scale, which, on the whole, forms a spatial distribution pattern of high in the north and south, and low in the middle. The amplitude of variation and elastic change of the runoff coefficient significantly increased after the 1990s. The high heat index of amplitude of variation of runoff coefficient area is found in the north of Dongyuan county. Compared with evaporation and vegetation coverage, the changing trends of rainfall and runoff coefficients as well its heat index of amplitude of variation have good consistency on the spatial distribution. The research provides a reference basis for identifying variability of water inflow of river basins under a changing environment.
  • WANG Qun, LU Lin, YANG Xingzhu
    2014, 33(6): 1059-1072. https://doi.org/10.11821/dlyj201406007
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    The security assessment of water resources system is the key basis for water resources management and regulation. By choosing the disturbance and response capabilities as the evaluation factors, this study built the water resource security evaluation index system. First, the main evaluating indicators are determined, including the water resources, tourism development, social economic, environment aspects. Then, using the water resources and tourism development datasets over the period of 1998-2012, this paper presented an empirical analysis of water resource security evaluation in Huangshan resort, combined with the method of set pair analysis. Results show that: (1) The interannual variation of the security index presents an increasing tendency, rising from 0.4158 in 1998 to 0.5826 in 2012 at its medium level. From the point of view of evaluation factors, a disturbance index showed a slowly upword trend and response capacity increased rapidly. These changes of the disturbance and response capabilities are the underlying cause of water resources security improvement in Huangshan resort. (2) The monthly variation of the security index has the pattern of"double peaks and two valleys"at its medium level. But there are monthly difference, especially October has extreme insecurity. The monthly variation of water resources system is mainly affected by disturbance factors. Thus, monthly water supply and sewage treatment capacity are not sufficient enough to improve the security of the water resource system. (3) The interannual variation of the security index with disturbance and response capabilities exists a strong positive correlation. However, the monthly variation of the security index with disturbance and response capabilities exists a negative correlation. The interannual variation of the security index with response capabilities shows high consistency, but response capabilities can not change the monthly variation of the security index. (4) The potential of water resources, tourism development, water use efficiency and pollutant capacity constitute the disturbance factor for system security; income and investment, technology and moral measures form response capabilities. Environmental background conditions, eco-water usage and tourism water usage are key factors affecting security of water resources system. Rainfall and tourism water usage triggering a series of socio-economic and environmental changes are important factors. However, same-day visitors growth, larger load streams and the reservoir water quality do not constitute important disturbance factors. Scenic ecological protection, capital investment and tourism revenues play a crucial role in improving the response capacity of water system security. On the one hand, the paper provides a new study viewpoint of the tourism water resources security research. On the other hand, it also provides a scientific basis for the water resource sustainable development of mountain tourism destination.
  • WANG Qi, MENG Jijun, MAO Xiyan
    2014, 33(6): 1073-1084. https://doi.org/10.11821/dlyj201406008
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    Tourism is identified to be capable of stimulating economic development in certain regions. However, tourist regions are experiencing a series of adverse effects with regard to local ecosystem associated with boosts in tourism. That is, the development of tourist region is able to manage a series of trade-offs between societal, economic and environmental goals. Given its integrated and dynamic land use form, tourist regions offer great samples to link physical and human systems and understand the anthropogenic effects and implications of land changes. Building on this premise, this paper seeks to model the physical-and human-induced landscape change by using Lijiang River Basin as a case. We employed a hybrid model of neighborhood analysis and Auto-logistic regression to project the likelihood map of land use distribution. Then, CLUE-S model is used to simulate future land use pattern under four policy-based scenarios: natural growth scenario, land planning scenario, resource conservation scenario and tourism development scenario. Several landscape indices are introduced to reveal the features of each pattern and to compare advantages of each scenario, which can provide scientific basis for future policy-making. Key results emerged: (1) Hybrid model of neighborhood analysis and auto-logistic regression is a more active and effective way, than the traditional logistic regression model is, to project the likelihood map of land use distribution. It helps to deal with the weakness of CLUE-s model on representing self-organizing character of land use change; (2) The Lijiang River Basin is a landscape dominated by the woodland and cultivated land. Vulnerability of landscape in the basin is primarily ascribable to the fragmentation of grassland and construction land and the fluctuated amount of water. To achieve an efficient land use in tourist region, a reasonable spatial regulation is more important than quantitative limits; (3) Tourism development requires a stable and diverse landscape. It indicates a necessity of controlling the interference of anthropogenic driven land use change on landscapes and managing the trade-off between socio-economic and eco-environmental land demand simultaneously. Result of this study may inform regional ecosystem management of ways to adapt sustainably to future change.
  • WANG Yaqin, WANG Zhengxing, DIAO Huijuan
    2014, 33(6): 1085-1096. https://doi.org/10.11821/dlyj201406009
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    Land cover change detection includes two categories: conversion (qualitative) and modification (quantitative). Both of them have close relation with temporal and spatial scales. The present paper explored land cover change during 2000, 2005, and 2010, by means of top-down method, using 250 m-16day MODIS time serials, 30 m-1year TM, and 0.6 m-6 year Quick-Bird data in Mt. Luya, Shanxi province, China. The results show: (1) Inter-annual MODIS-NDVI variation is estimated at 5%-10%, and intra-year MODIS-NDVI time serial has clear seasonality for most land cover types. The inter-annual change may be due to mixed results of climate variation and human activities. Therefore, it is necessary to de-couple the effect of nature from that of human beings in order to assess the efficiency of ecological project. (2) The intra-year change (seasonality) reflected by MODIS-NDVI means that inconsistency of TM acquisition time may lead to uncertainty for change detection since corresponding NDVI could be as much as 0.2. In transitional eco-zones, it is especially true because it is not easy to differentiate between actual change and seasonal change. To deal with this problem, normalization is recommended to minimize the difference resulted from seasonal variations. (3) Land cover type changes were found at clear-cut deforestation sites, some slow transition from grass to bush can be detected by 0.6 m Quick Bird data, but not by 30 m TM and 250 m MODIS. In conclusion: Landsat data have been successfully used in many operational database developments in the last 40 years; however, this triumph should not obscure its shortfalls in some specific fields. This study is such a case where vegetations have experienced a long history of disturbance-recovery, thus they may be not a typical land cover type in a 30-m scale. For this naturally transitional eco-zone, plus frequent human disturbance, Landsat data only is far from enough, let alone its inconsistent acquisition time. So, multi-source data should be applied to handle the uncertainties.
  • WANG Yun, ZHOU Zhongxue, GUO Zhongzhe
    2014, 33(6): 1097-1105. https://doi.org/10.11821/dlyj201406010
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    With a case study of Xi'an city, the landscape patterns of urban agriculture and the process of landscape fragmentation were analyzed from the perspective of time and space. Furthermore the relationship between the process of urban agricultural landscape fragmentation and the agro-ecosystem services provided by urban agriculture, and the impact of landscape changes of urban agriculture on its ecosystem services were studied. This research work enriches and improves the theories of urban agriculture from the view of landscape ecology, and provides the recommendation for government agencies on the land resources conservation and its utilization of urban agriculture and the decision-making of the eco-environmental protection and regional ecological security in Xi'an city. Based on the Landsat data, land use map and statistical data in Xi'an city, the concept of urban agricultural landscape was defined and the changes of the landscape pattern, the processes of landscape fragmentation of urban agriculture and its effects on agro-ecosystem services were also researched by employing the landscape indices, the coefficient analysis and the spatial analyst methods. The results showed that: (1) The patch density of urban agriculture landscape increases from 0.84 to 4.64 and the separation index rises from 0.15 to 0.76 in Xi'an city, the patch density and splitting index of urban agricultural landscape shows an increasing trend, and the fragmentation of urban agricultural landscape is obvious during the period 1999-2011. (2) There are strongly negative correlation between the isolation of urban agricultural landscape and the total value or partial value of ecosystem services of urban agro-ecosystem; The maximum decrease of the ecosystem services value is the waste disposal and soil formation service, while the maximum rate reduction is the value of food production service, down by 12.73%, and the minimum reduction is the value of entertainment culture service, by 1.93% in the process of agricultural landscape fragmentation. (3) The landscape of arable land, forest, water are fragmentized insignificantly, and the value of ecosystem services provided by the arable land, forest and water have a decline, while the aggregation of orchard rises, and the ecosystem services value provided by orchard increase from 1999 to 2011. During this period the low value zone of ecosystem services expands from urban to suburban areas. However, the fragmentation degree of urban agricultural landscape is lower in the suburbs than that in urban areas, which is in coincidence with the decrease of ecosystem services value provided by urban agro-ecosystem from suburban to urban areas.
  • YANG Xue, TAN Minghong
    2014, 33(6): 1106-1118. https://doi.org/10.11821/dlyj201406011
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    The development of rapid urbanization exerts influence in arable land and also deeply affects transformation of its functions, especially in the suburb of metropolises. Using Beijing as a case study, this paper establishes an evaluation index system of arable land functions, then standardizes data with extreme difference value method and determines index weights with the AHP method. Finally, we use weight sum method to calculate function values. The main conclusions include: (1) Production, ecological, cultural and social functions in per unit area of arable land were enhanced in almost all districts during the period 2004-2011. The spatial differences show that: production and social functions in outer suburban plain areas were higher than those in outer suburban mountain areas and inner suburban districts, ecological function in outer suburban plain areas was higher than that in outer suburban mountain areas, and cultural function in inner suburban districts was higher than that in outer ones. (2) The production functions of grain, vegetables and melons in outer suburban plain areas were all stronger, but the agricultural pollution in these areas was more serious. In addtion, influenced by distance from city center, the demand of cultural function in inner suburban areas was higher than that in outer suburban districts. (3) The total function of arable land was enhanced in most districts during the period 2004-2011. Similarly, influenced by terrain condition and central economic radiation, the total function of arable land in the outer suburban plain areas was stronger than that of other districts. (4) According to the proportion of total function, arable land can be divided into four categories: production type (outer suburban plain areas), ecological type (inner suburban areas), cultural type (Fengtai and Mentougou districts), and social type (outer suburban mountainous areas).
  • ZHOU Tianyu, WANG Ying
    2014, 33(6): 1119-1128. https://doi.org/10.11821/dlyj201406012
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    Based on the research of financial development and economic growth, the paper tries to do research on geographic distribution of financial institutions and economic growth. Aiming at the problem of correlation between geographical distribution of financial institutions and economic growth, we applied data from counties of Guangdong to demonstrate the importance of the spatial concentration of financial institutions and its impact on economic growth. Research results show that there exist an inverted U-shaped relationship between spatial concentration of financial institutions and economic growth in Guangdong at the county level. In the beginning the relationship is positive, but this correlation wanes with the gathering enhanced. We find that financial institutions concentration could partly explain the differences in economic growth among counties of Guangdong; at the same time, Guangzhou which played the role of the regional center of financial institutions concentration influences the relationship between financial institutions agglomeration and economic growth in other counties.
  • SUN Yuhuan, JI Xiaoxu
    2014, 33(6): 1129-1139. https://doi.org/10.11821/dlyj201406013
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    Human capital has become increasingly important for economic growth in the 21st century. As an important means of developing human capital, education in China has become a strategic priority. The country's investment in education has been increasing these years. However, the relative lack of regional educational investment has led to regional disparity in compulsory education. This has resulted in an unequal distribution of human capital across China, thus exacerbating the differences in regional economic development. This study analyzes and compares the regional differences in education investment and the elasticity of GDP by using panel data from 2001 to 2010 of 31 Chinese provinces and a micro-panel data model of multidimensional clusters derived from the indexes of per capita education years, per capita education funds, and the proportion of education funds to GDP. The study finds that the effect of education at different levels of development differs across development levels and types of economies. In nine of the central and western Chinese provinces that have a weak economic foundation and low level of education development—Yunnan, Gansu, Guizhou, Ningxia, Hainan, Xinjiang, Shanxi, Qinghai, and Xizang—there is a negative relationship between education funds and economic growth, with GDP lacking elasticity. On the other hand, in the other 22 provinces, which have a better economic foundation, GDP is elastic and interacts negatively with education. Among these provinces, Beijing, Shanghai and Tianjin have the highest elasticity coefficient. The paper goes on to suggest that the government should advocate equality in education, promote compulsory education in rural areas, and formulate different education priority development strategies aimed at different regional development levels of both economy and education. Furthermore, the government should not only ensure that the state is the main investor in education funds but also encourage the education funds raised by enterprises and individuals by ensuring better policy decisions.
  • QIAN Minghui, HU Ridong
    2014, 33(6): 1140-1150. https://doi.org/10.11821/dlyj201406014
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    By the analysis of spatial distribution and spatial correlation of Chinese regional financial industry on the level of prefecture-level and above administrative region in China, we take the spatial location entropy difference as the index to measure the spatial radiation ability of the regional financial centers of China. Then under the theoretical framework of new geographical economics theory, we expand the traditional spatial regression model and make the factor analysis of the spatial radiation ability of the regional financial centers. From the empirical results of spatial radiation ability impact factors of the regional financial centers in China, we find that there are strong spillover effects of regional financial industry and regional financial centers have significant spatial radiation abilities. The spatial radiation ability of the regional financial center does not only relate to the regional economy, financial environment and human support, but also is affected by economic factors of adjacent regions and the gap between adjacent areas. Moreover, the spatial diffusion of regional financial industry is different from the traditional industries, which has its inherent characteristics that the influence of trade activity and transportation conditions is not significant. Therefore, we suggest that the Chinese government should formulate industrial policies from the three aspects of itself, the adjacent regions and the regional gap to improve the spatial radiation ability of regional financial centers. By the means of creating suitable spatial carrier and policy platform for the development of China's regional financial centers, promoting the regional financial industry cluster development, accelerating financial capital flows, integrating financial industry resources and markets, promoting the optimal allocation of social resources and the effectiveness of allocation of financial resources, avoiding vicious competition, Chinese regional financial center can achieve its goals to promote economic and social development.
  • CAO Fangdong, HUANG Zhenfang, YU Fenglong, WU Limin
    2014, 33(6): 1151-1166. https://doi.org/10.11821/dlyj201406015
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    By using Data Envelopment Analysis (DEA) method, this paper first comprehensively measures and calculates the tourism efficiency of China's National Scenic Areas. Then, methods of Standard Deviation Ellipse and Barycentric Coordinates are adopted for exploring how the gravity centers of travel efficiency of China's National Scenic Areas evolves and for analyzing the important factors which affect the evolution path and its mechanism. Results are shown as follows: (1) Generally, the tourism efficiency of China's National Scenic Areas is not high, with a comparatively low variation. The comprehensive efficiency, pure technical efficiency and scale efficiency are characterized by obvious fluctuation, which illustrates, in the early stage of the reform and opening up, that the tourism development of scenic areas benefited from scale-investment and effective monetary capital investment is the main measure to promote tourism development. In addition, the average efficiency value shows an overall decline, which indicateds most scenic areas are in a state of inefficiency, lack of DEA optimum state so that the production unit of scenic areas shows certain resources redundancy and inefficient development. (2) Viewed from the distribution of the gravity centers on the whole, they are mainly located between 107°11'E-118°37'E and 29°02'N-38°55'N, an east-west span of about 11° and south-north span of about 9°; seen from the evolution of travel efficiency gravity centers, the comprehensive efficiency varies the most, but on the whole the paths all change from west by south first to east by north, then back to west by south. Meanwhile, the trend of east by north of the gravity centers of the scale efficiency and total factor productivity are relatively small, while the trends of the comprehensive efficiency and pure technical efficiency change greatly.(3) By analyzing the evolution driving mechanism of spatial layout of scenic areas travel efficiency, we can find out that the level of economic development, resources endowment, industrial structure, transportation development, information technology and system supply are the important factors which affect the gravity centers shift of the travel efficiency, and these factors promote the dynamic evolution of spatial pattern of the travel efficiency. Through optimizing the industrial structure, introducing advanced technology, making perfection of the market mechanism, scientific government regulation and improvement of resources endowment, we can effectively raise the travel efficiency of scenic areas.
  • ZHENG Qiufeng, ZHANG Maoheng, LI Jijun, SHU Qiang, CHEN Ye, XIAO Jiayi, ZHAO Zhijun
    2014, 33(6): 1167-1177. https://doi.org/10.11821/dlyj201406016
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    We have established the stratigraphic sequence of DJH-2 core, Dajiuhu Basin in Shennongjia Mountain. AMS dating and amino acid dating methods are applied to determine the age. Combined with climate stratigraphic correlation, the age of the core bottom is about 275. 8 ka. According to the results of pollen analysis and sedimentary lithology, we have divided the vegetation succession and paleoclimate evolution into six stages since the late Middle Pleistocene. Stage one (275.8-245.0 ka): It was cold and dry, and coniferous forests and alpine meadows developed. Stage two (245.0-188.0 ka): It covered with temperate evergreen and deciduous broad-leaved forests. And it was warmer than stage one. Stage three (188.0-129.0 ka): The paleoclimate condition was similar to stage one, and its major vegetation shifted from coniferous forests to mountain meadow. Stage four (129.0-71.8 ka): The paleoclimate was warm and humid. And it was suitable for temperate broadleaf forests. Stage five (71.8-15.0 ka): The middle pollen subzone had the most of pollen concentration. The pollen belt reflected unstable climate but totally cold and wet. Stage six (15.0-1.0 ka): It was warm and humid to fit for the subtropical evergreen and deciduous broad-leaved forests. In comparison with oxygen isotope sequences of stalagmites (Sanbao caves) in East Asia and marine sediments (SPECMAP), the results show that the past vegetation changes of Shennongjia area responded sensitively to the climate changes. The variation of palynological assemblages followed climate changes, especially some species. The change of rhythm was similar to the global glacial-interglacial climate cycle. The climate change was induced by the ice volume from the high latitudes of the northern hemisphere. And it was also affected by solar radiation at low latitudes. The two factors played an important part in pollen concentration variation.
  • ZHOU Liang, HUANG Chunchang, ZHOU Yali, PANG Jiangli, ZHA Xiaochun, MAO Peini, ZHANG Yuzhu
    2014, 33(6): 1178-1192. https://doi.org/10.11821/dlyj201406017
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    The Hanjiang River is the biggest tributary of the Yangtze River and it will supply water resource to Beijing through the national"South-to-North Water Diversion Project". Holocene slackwater deposits along the river channels were used to study the magnitude and frequency of the paleoflood that occurred prior to gaged records and historical datasets all over the world. These pedo-stratigraphic sequences are studied using a multi-discliplinarily approach to reconstruct Holocene hydro-climatic variations. Our field investigations was carried out in the upper reaches of Hanjiang River valley. Four bedsets of palaeoflood slackwater deposit (SWD) were found interbedded in the eolian loess-soil profile at the GXH site, which were identified by the sedimentary criteria and analytical results. Analytical results, including grain-size distribution and magnetic susceptibility, indicate that these SWD consists of sandy silt, sourced from the suspended sediment load of the palaeo-floodwater. Each bedset of the SWD represents one group of palaeoflood event. OSL dating for the quarts grains at different sizes separated from the samples by using the single aliquot regenerative-dose (SAR) protocol. All OSL measurements were made on a Ris? TL/OSL DA-20 dating system using a blue light (470 nm) for optical stimulation. The dose rates were converted and calibrated by using the measured concentrations of U, Th, K elements. The OSL dates were figured out by using the Age.exe software written by Grün (2003). According to the optically stimulated luminescence (OSL) dating method in combination with archaeological dating of retrieved anthropogenic remains, and with pedostratigraphic correlations with the previously studied Holocence pedo-stratigraphy in the upper reaches of Hanjiang River valley, these palaeoflood events were dated to 12500-12000 a (SWD 1),7500-7200 a (SWD 2), 3100-2800 a (SWD 3), 1800-1700 a (SWD 4), respectively. These flooding events are therefore considered to be a regional expressions of known climate events in the northern hemisphere and demonstrate that Holocene climate was far from stable. In the reconstructed temperature time series based on high-resolution climatic proxies from tree-rings, stalagmites, ice-cores and lake sediments across the world, these extraordinary palaeoflood events are well correlated to the decline time of global climatic or climatic transition. Highly unstable climate may result in great variation of precipitation. which can cause floods and droughts. These results are of great significance in mitigating flood disasters, and in hydraulic engineering, as well as in understanding hydrological response to global climatic change.