西藏自治区土壤侵蚀特点及现状

西藏自治区地域辽阔,土壤侵蚀复杂多样。本文在野外调查的基础上,对西藏自治区土壤侵蚀特点作了全面论述,并对西藏自治区不同类型土壤侵蚀区的土壤侵蚀现状做了较全面的分区评价。同时取雅江中游地区19个县作为典型区域,利用1999年1:20万TM遥感图像土壤侵蚀解译结果,对该典型区域的土壤侵蚀现状作了定量评价。最后根据评价结果,对西藏自治区土壤侵蚀的发展趋势做了预测。     

西藏土壤侵蚀敏感性分布规律及其区划研究

西藏土壤侵蚀类型多样,其中水土流失、土地沙漠化、冻融侵蚀以及崩塌、滑坡和泥石流等侵蚀类型广泛分布,危害严重。本文对前三种土壤侵蚀类型敏感性特点及其分布规律进行了评价,在此基础上,作出了西藏土壤侵蚀敏感性综合区划,并对各分区主要特点作了简要的描述。为土壤侵蚀防治和生态环境保护与建设提供依据。     

西藏冻融侵蚀分级评价

冻融侵蚀是仅次于水蚀和风蚀的第三大土壤侵蚀类型,由于受诸多因素限制,到目前为止,国内外对其研究甚少,有关其强度分级评价方面的研究则更为鲜见。本文在综合分析冻融侵蚀影响因子的基础上,选取气温年较差、坡度、坡向、植被、年降水量、土壤等六个因子作为西藏冻融侵蚀分级评价指标,用加权加和的方法建立了适合西藏自治区的冻融侵蚀相对分级评价模型,并在地理信息系统软件的支持下实现了西藏自治区冻融侵蚀相对分级。最后,利用分级结果对西藏自治区冻融侵蚀进行了综合评价。结果表明,西藏冻融侵蚀具有分布范围广,不同强度冻融侵蚀空间分异明显,冻融侵蚀地区分布差异明显等特点。     

界定西藏冻融侵蚀区分布的一种新方法

冻融侵蚀区的界定是目前青藏高原冻融侵蚀研究需要解决的重要课题之一。根据笔者和前人相关成果，该文提出了青藏高原冻融侵蚀区界定的理论依据，并在GIS技术支持下，对青藏高原的主体——西藏自治区的冻融侵蚀进行界定，系统分析西藏冻融侵蚀区的分布规律。西藏自治区冻融侵蚀区分布具有以下特点：1)冻融侵蚀区分布面积广，占西藏自治区国土面积的55．3％；2)雅江南北冻融侵蚀区分布差异明显，雅江以北分布范围广，雅江以南范围小；3)地区分布差异明显，冻融侵蚀区集中分布在那曲和阿里地区；4)冻融侵蚀是那曲、阿里、拉萨、昌都、日喀则等地区(市)最主要的土壤侵蚀类型。     

我国土壤侵蚀与地理环境的关系

本文论述我国土壤侵蚀类型与自然地带性和非地带性因素的关系,分析影响侵蚀强度时空分布和侵蚀泥沙输移的环境因素及流域条件。     

安徽省土壤侵蚀空间分布及其与环境因子的关系

基于USLE和GIS空间分析技术,对安徽省土壤侵蚀空间分布进行了定量研究,分析了土壤侵蚀空间分布与地形、土壤类型、土地利用方式的关系。结果表明:安徽省2002年平均土壤侵蚀模数为249.5t/km²·a,土壤侵蚀总量为33599148t/a。土壤侵蚀空间分布呈块状分布特征。淮北平原地区土壤侵蚀较弱,皖南丘陵山区和皖西大别山区土壤侵蚀较严重。在不同高程带上,200~500m高程带土壤侵蚀最强;不同坡度等级中,15°~25°坡度上的土壤侵蚀最强,>35°坡地上则较弱;不同坡向中,东南坡土壤侵蚀最强,其次是东坡;不同用地类型的土壤侵蚀程度不同,草地的土壤侵蚀最为严重,其次是林地;在各种土壤类型中,紫色土和黄褐土的土壤侵蚀最为突出,棕壤的土壤侵蚀微弱。     

基于GIS和RUSLE的滇西北山区土壤侵蚀空间特征分析——以云南省丽江县为例

土壤侵蚀空间分布特征,是进行土壤侵蚀防治规划、实践的重要基础与依据。研究以云南省丽江县为例,应用RUSLE估算了县域土壤侵蚀量,并基于G IS的空间统计分析功能,分析了土壤侵蚀在海拔、坡度与土地利用类型等方面的空间分布特征。结果表明,全县平均土壤侵蚀模数为52.50 t/(hm2.a),属于强度侵蚀,县域东部的金沙江沿岸、3 500~6 000 m高程带、25°~90°坡度带,以及裸地与荒草地、旱地等不同类型区域是研究区土壤侵蚀治理的重点地区。     

20世纪末中国土壤侵蚀的空间分布特征

通过对中国2000年第二次土壤侵蚀遥感调查成果的分析,讨论了20世纪末中国土壤侵蚀空间分布特点。结果表明,水土流失仍然是我国持续影响面最大的环境问题。西部是我国土壤侵蚀的主要分布地区,轻度侵蚀对整个土壤侵蚀格局影响最大。水蚀的分布明显体现出地形的影响,轻度水蚀基本上分布在山地丘陵区 (含黄土地形区),严重水蚀近半分布在黄土地形区。轻度水蚀主要分布在耕地、林地、草地。严重水蚀、轻度风蚀面积均约半数分布在草地,各类草地的保护与整治均应是水、风蚀区水土保持的重要内容。土壤资源中,黄绵土是受到土壤侵蚀威胁最严重的类型。但对我国土壤侵蚀的进一步分析还需要更多对方法和相关数据分析的研究工作。     

西藏北部典型湖盆区繁殖鸟类调查初报

西藏北部湖盆区是西藏湿地分布最为集中的区域,鸟类资源丰富。2016-2018年6-7月对该区的繁殖鸟类进行了调查,共记录到鸟类12目24科64种,占西藏自治区鸟类总数492种的13.01%。西藏北部湖盆区鸟种组成以雀形目和雁形目的鸟种最多,在区系构成上以古北界鸟类为主,其中13种鸟类为国际公约保护和我国重点保护的鸟类资源。     

西藏自治区近30年山洪灾害时空分布特征

山洪灾害时空分布特征分析是区域山洪防治规划、监测预警的基础。通过收集西藏自治区1983—2015年的历史山洪灾害数据,利用地理信息时空统计、数据挖掘分析等方法对西藏山洪灾害的时空分布特征及突变情况进行分析,并探讨了山洪与不同降水指标的分布关系。结果表明:(1)西藏自治区1983—2015年均发生山洪灾害32次,主要在7、8月份,其逐年变化呈y=0.012x~3-0.4123x~2+4.5769x-7.748的三次函数增长,且周期变化存在多时间尺度特征,主要表现在33a特征时间尺度下,周期变化具有全域性,平均周期为21a;(2)西藏山洪主要分布在日喀则、山南和林芝三个地级市,仁布和察隅两个县域以及西藏东、南部的索曲河流域,雅鲁藏布江中游、拉萨河流域的山区,分布密度在0~3.29次/100 km~2,1983—1993年山洪分布方向趋势性最明显,2005—2015年山洪分布范围最广,随机性最强,三个时段平均中心均位于拉萨市,中心趋势变化不大;(3)1997年和2009年为西藏山洪突变的年份,突变主要集中在雅鲁藏布江中游及拉萨河流域,1997年密度变化范围在-0.15~1.15次/100 km~2,而2009年为-1.13~0.97次/100 km~2;(4)以30°N和90°E线为界,降水指标的分布与西藏山洪灾害的分布具有一定的相似性。不同类型的降水指标山洪灾害集中分布的降水区间不同,其中年均最大60分钟降水指标对山洪灾害分布较为敏感。这些结果对促进山洪灾害数据挖掘与时空分析理论、西藏地区山洪灾害科学减灾等具有重要的理论和现实意义。     

西藏高原土壤侵蚀评价体系及监测方法

西藏高原土壤侵蚀营力多样,侵蚀类型复杂,其评价与动态监测方法一直为人们所关注,根据多年对西藏高原土壤侵蚀的调查研究,从西藏高原土壤侵蚀区域分布特征出发;提出西藏高原土壤侵蚀应划分为自然侵蚀区和人为加速侵蚀区,分别采用土壤侵蚀潜在危险及土壤侵蚀分类分级的评价体系.前者采用人机交互式遥感动态监测方法,后者采用土壤侵蚀因子数据库与土壤侵蚀模型法相结合进行动态监测.     

西藏冻融侵蚀的分级和评价

Freeze-thaw erosion is the third largest soil erosion type after water erosion and wind erosion. Restricted by many factors, few researches on freeze-thaw erosion have so far been done at home and abroad, especially those on the assessment method of freeze-thaw erosion. Based on the comprehensive analysis of impact factors of free-thaw erosion, this paper chooses six indexes, including the annual temperature range, annual precipitation, slope, aspect, vegetation and soil, to build the model for relative classification of freeze-thaw erosion using weighted and additive methods, and realizes the relative classification of the freeze-thaw erosion in Tibet with the support of GIS software. Then a synthetic assessment of freeze-thaw erosion in Tibet has been carried out according to the relative classification result. The result shows that the distribution of freeze-thaw eroded area is very extensive in Tibet, accounting for 55.3% of the total local land area; the spatial differentiation of freeze-thaw erosion with different intensities is obvious; and the difference in distribution among different regions is also obvious.     

The classification and assessment of freeze-thaw erosion in Tibet

Freeze-thaw erosion is the third largest soil erosion type after water erosion and wind erosion. Restricted by many factors, few researches on freeze-thaw erosion have so far been done at home and abroad, especially those on the assessment method of freeze-thaw erosion. Based on the comprehensive analysis of impact factors of free-thaw erosion, this paper chooses six indexes, including the annual temperature range, annual precipitation, slope, aspect, vegetation and soil, to build the model for relative classification of freeze-thaw erosion using weighted and additive methods, and realizes the relative classification of the freeze-thaw erosion in Tibet with the support of GIS software. Then a synthetic assessment of freeze-thaw erosion in Tibet has been carried out according to the relative classification result. The result shows that the distribution of freeze-thaw eroded area is very extensive in Tibet, accounting for 55.3% of the total local land area; the spatial differentiation of freeze-thaw erosion with different intensities is obvious; and the difference in distribution among different regions is also obvious.     

西藏水土流失敏感性评价及其空间分异规律

以水土流失通用方程为理论基础,运用数学模型和GIS分析相结合的方法,将降水、地貌、土壤和植被因子对西藏水土流失敏感性的影响程度,划分为极敏感、相当敏感、敏感、较敏感和不敏感5个等级,并生成各单因素评价图。在Arcinfo中完成单因素图的叠加分析,得到西藏水土流失敏感性综合评价图。在此基础上,探讨了西藏特殊高原环境下的水土流失敏感性高低的分布规律及其在不同主导因子作用下的水土流失敏感性空间分异,提出了西藏水土流失治理的优先区,为水利、公路和农牧等部门进行专题规划和治理提供依据。     

Assessment and spatial distribution of sensitivity of soil erosion in Tibet

Based on Universal Soil Loss Equation and methods of mathematics model and GIS analysis, this study classified influence of precipitation, soil, topography and vegetation upon sensitivity of soil erosion into five different degrees which are extreme sensitivity, quite sensitivity, sensitivity, less sensitivity and no sensitivity. Assessment map of each factor was generated separately. Integrated assessment map of sensitivity of soil erosion has also been drawn by overlapping function with Arcinfo. Furthermore, the study analyzed distribution characteristics and spatial difference of sensitivity of soil erosion under special plateau environment of Tibet. According to sensitivity degree, some important controlling regions was confirmed so that departments of water conservancy, traffic management and agriculture could make scientific and reasonable decisions for their respective subject planning.     

西藏水土流失敏感性评价及其空间分异规律

Based on Universal Soil Loss Equation and methods of mathematics model and GIS analysis, this study classified influence of precipitation, soil, topography and vegetation upon sensitivity of soil erosion into five different degrees which are extreme sensitivity, quite sensitivity, sensitivity, less sensitivity and no sensitivity. Assessment map of each factor was generated separately. Integrated assessment map of sensitivity of soil erosion has also been drawn by overlapping function with Arcinfo. Furthermore, the study analyzed distribution characteristics and spatial difference of sensitivity of soil erosion under special plateau environment of Tibet. According to sensitivity degree, some important controlling regions was confirmed so that departments of water conservancy, traffic management and agriculture could make scientific and reasonable decisions for their respective subject planning.     

Soil erosion in China based on the 2000 national remote sensing survey

This paper discussed the spatial distribution of soil erosion in China at the end of the 20th century based on the second national soil erosion survey. The result indicated soil erosion is still the prime environmental problem in China. Soil erosion mainly occurs in the western regions of China, and the slight erosion type, ion the whole, exerts the greatest impact on soil erosion pattern. The distribution of water erosion shows the impact of landforms: slight water erosion mainly in mountainous and hilly areas, and half of violent water erosion on the loess landforms. Farmland, forestland and grassland are the major land use types of slight hydraulic erosion distribution, while the serious hydraulic erosion and slight wind erosion mainly occur on grassland. Thus, the conservation of the grassland is the key to either hydraulic and wind erosion control. The huangmian soil (a major type of cultivated soil developed from loess mother material) is the one facing the most serious threat from soil erosion in Chinas soil resources. Further discussion on the soil erosion distribution still needs more research on the method and relevant data analysis.     

Soil erosion in China based on the 2000 national remote sensing survey

This paper discussed the spatial distribution of soil erosion in China at the end of the 20th century based on the second national soil erosion survey. The result indicated soil erosion is still the prime environmental problem in China. Soil erosion mainly occurs in the western regions of China, and the slight erosion type, ion the whole, exerts the greatest impact on soil erosion pattern. The distribution of water erosion shows the impact of landforms: slight water erosion mainly in mountainous and hilly areas, and half of violent water erosion on the loess landforms. Farmland, forestland and grassland are the major land use types of slight hydraulic erosion distribution, while the serious hydraulic erosion and slight wind erosion mainly occur on grassland. Thus, the conservation of the grassland is the key to either hydraulic and wind erosion control. The huangmian soil (a major type of cultivated soil developed from loess mother material) is the one facing the most serious threat from soil erosion in Chinas soil resources. Further discussion on the soil erosion distribution still needs more research on the method and relevant data analysis.