中国山地分类研究

中国是多山的国家,山地类型多样复杂,开展山地分类研究很有必要。基于前人山地定义分析基础上,确定中国山地分类原则和基本思路,提出中国山地分类系统,共计分出6个类型,其中3个属于大尺度类型,适用于全国和跨省(区)制图,其余类型适用于县(区、市)制图;同时提出了每个类型的划分标准。基于SRTM 90 m分辨率的DEM数据,确定出大尺度类型,即山地大区、山地带和山地大类的分布范围,编制了相应的图件,并对各类型面积作了计量统计。结果表明,分布于不同海拔带的丘陵面积占中国陆地面积的18.2%;起伏度大于200 m的山地面积占中国陆地面积的55.2%,其中,低山、中山和高山面积分别占16.5%、14.8%和18.5%,高中山和极高山面积分别为4.3%和1.1%。

重庆万州区山地分类定量化研究

文章在GIS技术支持下,基于水文分析模型,通过DEM数据,结合山地综合分类模型,以重庆市万州区为例,对山地进行定量化分类研究,结果表明:以负地形洼地贡献区域作为山地相对高程的起算面,完全摆脱了人为因素的影响,解决了一直以来难以确定山地相对高度起算范围的难题;以负地形洼地深度作为山地相对高程是正确可行的,且能快速获取山地的相对高程;以山地表面积代替投影面积计算山地率更切合实际。

2002年夏季长白山天池火山区的地震活动研究

20 0 2年6月以来,长白山天池火山区的地震活动明显增加.本文利用2 0 0 2年夏季布设在长白山天池火山区15套宽频带流动地震台站的记录资料,对天池火山区的地震活动进行了研究.地震观测结果表明,2 0 0 2年夏季长白山天池火山日平均地震发生频次超过30次.地震主要位于长白山天池西南部和东北部两个区域,震源深度较浅,离地表的深度一般小于5km .天池西南部和东北部的地震,b值存在较大的差异.火山区地震记录的频谱分析和时频分析结果表明,这些地震主要为火山构造型地震.HSZ和DZD等台站地震记录中丰富的低频成分,可能与台站附近的局部介质或断层带有关.我们认为2 0 0 2年夏季频繁发生的地震和小震震群活动是由火山深部活动诱发的局部断裂活动引起.

Comparison between the Medullary Indexes of Hairs from Apodemus orestes and A.draco,with Discussion about the Taxonomic Status of A.orestes

The taxonomic status of long-tailed field mouse (Apodemus orestes) is still uncertain up to now.Some scholars regarded it as a subspecies or a synonym of dragon field mouse (A.draco),while other scholars considered it a valid species.In the study,five specimens of adult long-tailed field mouse,dragon field mouse and Chevrier's field mouse (A.chevrieri) (as a contrast) were chosen respectively.After treated,with the eyepiece micrometer in the inverted microscope,we made measurements of the widths of hairs and medullas and then calculated the medullary indexes of straight guard hairs from around the mouth,head,back,abdomen and forelimb of each species.The results indicate that,viewing at each of the five parts and the mixture of the five parts,there are no significant differences between A.orestes and A.draco,Significant differences can be found between A.orestes & A.chevrieri and A.draco & A.chevrieri though.The standpoint that A.orestes was listed as a valid species is not supported by this study.

Classification and Gradation of Cultivated Land Quality in Bishan County of Chongqing, China

The conflicts among food security, economic development and ecological protection are the “sticking point” of undeveloped southwestern mountainous areas of China. The objectives of this study are to identify appropriate inte- grated indicators influencing the classification and gradation of cultivated land quality in the southwestern mountainous area of China based on semi-structure interview, and to promote the monitoring of cultivated land quality in this region. Taking Bishan County of Chongqing as a study case, the integrated indicators involve the productivity, protection, ac- ceptability, and stability of cultivated land. The integrated indicators accord with the characteristics of land resources and human preference in southwestern mountainous area of China. In different agricultural zones, we emphasize different indicators, such as emphasizing productivity, stabilization and acceptability in low hilly and plain agricultural integrative zone (LHP-AIZ), protection, productivity and stability in low mountain and hill agro-forestry ecological zone (LMH-AEZ), and acceptability in plain outskirts integrative agricultural zone (PO-IAZ), respectively. The pronounced difference of classification and gradation of cultivated land, regardless of inter-region or intra-region, is observed, with the reducible rank from PO-IAZ, LHP-AIZ to LMH-AEZ. Research results accord with the characteristics of assets management and intensive utilization of cultivated land resources in the southwestern mountainous area of China. Semi-structure interview adequately presents the principal agent of farmers in agricultural land use and rural land market. This method is very effective and feasible to obtain data of the quality of cultivated land in the southwestern mountainous area of China.

Quantifying land degradation in the Zoige Basin,NE Tibetan Plateau using satellite remote sensing data

Considerable efforts have been dedicated to desertification research in the arid and semi-arid drylands of central Asia. However,there are few quantitative studies in conjunction with proper qualitative evaluation concerning land degradation and aeolian activity in the alpine realm. In this study,spectral information from two Landsat-5 TM scenes(04.08.1994 and 28.07.2009,respectively) was combined with reference information obtained in the field to run supervised classifications of eight landscape types for both time steps. Subsequently,the temporal and spatial patterns of the alpine wetlands/grasslands evolutions in the Zoige Basin were quantified and assessed based on these two classification maps. The most conspicuous change is the sharp increase of ~627 km^2 degraded meadow. Concerning other land-covers,shallow wetland increases ~107 km^2 and aeolian sediments(mobile dunes and sand sheets) have an increase of ~30 km^2. Considering the deterioration,an obvious decrease of ~440 km^2 degraded wetland can be observed. Likewise,decrease of deep wetland(~78 km^2),humid meadow(~80 km^2) and undisturbed meadow(~88 km^2) were determined. These entire evolution matrixes undoubtedly hint a deteriorating tendency of the Zoige Basin ecosystem,which is characterized by significantly declined proportion of intact wetlands,meadow,rangeland and a considerable increase ofdegraded meadow and larger areas of mobile dunes. In particular,not only temporal alteration of the landcover categories,the spatial and topographical characteristics of the land degradation also deserves more attention. In the alpine rangelands,the higher terraces of the river channels along with their slopes are more liable to the degradation and desertification. This tendency has significantly impeded the nomadic and agriculture activities. The set of anthropozoogenic factors encompassing enclosures,overgrazing and trampling,rodent damaging and exceedingly ditching in the wetlands are assumed to be the main controlling mechanisms for the landscape degradation. A suite of strict protection policies is urgent and indispensable for self-regulation and restoration of the alpine meadow ecosystem. Controlling the size of livestock,less ditching in the rangeland,and the launching of a more strict nature reserve management by adjacent Ruoergai,Maqu and Hongyuan Counties would be practical and efficacious in achieving these objectives.

Engineering geological classification of the structural planes for hydroelectric projects in Emeishan Basalts

The scale and characteristics of rock mass are important indexes of the rock mass structural plane classification. This paper firstly analyzes the spatial distribution characteristics, the structural plane types （original structural plane, tectonic structural plane and hypergenic structural plane） and the associated features of the Emeishan basalts and then studies the classification schemes of the built hydropower structure planes of different rock areas （the east district, the central district and the west district） in the Emeishan basalt distribution area, Southwest China. Based on the analysis and comparison of the scale and the engineering geological characteristics of the typical structure planes in the basalt hydroelectric Stations, the types of structural planes are used in the first order classification. The secondary order classification is made by considering the impact factors of rock mass quality, e.g., the state of the structural planes, infilling, joint opening, extending length, the grade of weathering and strength. The engineering geological classification for Emeishan basalt is proposed. Because there are no evidences of a large structure presenting in study area, the first-order （Ⅰ） controlling structural planes do not appear in the classification, there only appear Ⅱ, Ⅲ, Ⅳ and Ⅴ grade structural planes influencing the rock-mass quality. According to the different rock-block types in bedding fault zone, the second-grade （Ⅱ） structural planes consisted of bedding fault zone is further classified into Ⅱ1, Ⅱ2 and Ⅱ3. The third-grade （Ⅲ） structural planes constructed by intraformational faulted zones are not subdivided. According to the different characteristics of intrusion, alteration and weathering unloading structural planes, the Ⅳ grade structure plane is divided into Ⅳ1, Ⅳ2 and Ⅳ3. According to the development characteristics of joints and fractures, the V grade structure plane is divided into fracture Ⅴ1 and columnar joint Ⅴ2. In all, the structural planes are classified into four groups with nine subsets. The research proposes the engineering geological classification of the structural plane for the hydropower project in the Emishan basalts, and the result of the study has a potential application in similar regions.

Landslide Susceptibility Mapping by Using Landslide RatioBased Logistic Regression:A Case Study in the Southern Taiwan

The object of the research is to compare the model performance and explain the error source of original logistic regression landslide susceptibility model(abbreviated as or-LRLSM) and landslide ratio-based logistic regression landslide susceptibility model(abbreviated as lr-LRLSM) in the Chishan watershed with a serious landslide disaster after 2009 Typhoon Morakot. The landslide inventory induced by 2009 Typhoon Morakot in South Taiwan is the main research material, while the Chishan watershed is the research area. Six variables, including elevation, slope, aspect, geological formation, accumulated rainfall, and bank erosion, were included in the two models. The performance of lr-LRLSM is better than that of or-LRLSM. The Cox & Snell R2, Nagelkerke R2 value, and the area under the relative operating characteristic curve(abbreviated as AUC) of lrLRLSM is larger than those of or-LRLSM, and the average correct ratio for the lr-LRLSM to predict landslide or non-landslide is larger than that of orLRLSM by 5.0%. The increase of the average correct ratio(abbreviated as ACR) difference from or-LRLSM to lr-LRLSM shows in slope, revised accumulated rainfall, aspect, geological formation and bank erosion variables, and only light decreases in elevation variable. The error sources of continuous variables in building the or-LRLSM is the dissimilarity between the distribution of landslide ratio and production of coefficient and characteristic values, while those of categorical variables is due to low correlation of landslide ratio and the coefficient value of each parameter. Using the classification of landslide ratio as the database to build logistic regression landslide susceptibility model(abbreviated as LRLSM) can revise the errors. The comparison of or-LRLSM and lr-LRLSM in the Chishan watershed also shows that building the landslide susceptibility model(abbreviated as LSM) by using lr-LRLSM is practical and of better performance than that by using the or-LRLSM.

Response of Asiatic ibex(Capra sibirica) under Climate Change Scenarios

We investigated the effects of climate change on the distribution of the Asiatic ibex(Capra sibirica)in eastern Tajikistan.No existing climate change studies have been conducted on the habitat of a wild goat species in Asia.We conducted ecological niche modelling to compare potential present and future distributions of suitable environmental conditions for ibex.Projecting to 2070,18%(2689 km^2)of the current suitable areas would be lost,mostly located in the southeastern and northwestern regions of the study area.However,new suitable habitats could expand outside the current ibex range—about 30%(4595 km^2)expansion until 2070.We found that the elevation,terrain roughness,seasonal temperature,and precipitation of warmest quarter were the most important factors in the models and had strong correlations to ibex distribution.The losses in the southeastern portion overlapped most of the current locations of ibex in that region.These losses were observed in the much lower elevations of the study area(3500 m to 4000 m).When considering both loss and gain,the ibex could see a net expansion to new suitable habitats.About 30%(1379 km^2)of the average habitat gains for the Asiatic ibex in 2070 showed a shift to northern lower temperature habitats.Our results are beneficial in planning for the potential effects on biodiversity conservation in the eastern mountain region of Tajikistan under climate change scenarios.Special attention should be given to the ibex populations in the southeastern region,where habitats could become unsuitable for the species as a result of the climate-induced effects on the mountain ecosystem.