Monitoring the sandstorm during spring season 2002 and desertification in northern China using SSM/I data and Getis statistics

A massive sandstorm enveloped most part of northern China during the spring season 2002. Monitoring the evolution of sandstorm and desertification has become one of the most serious problems for China's environment. Since 1989, one of the most advanced and operational passive microwave sensors is the DMSP SSM/I (special sensor microwave imager) operated at seven channels (19, 37, 85 GHz with the vertical and horizontal polarization and 22 GHz with vertical polarization only). In this paper, the sandstorm and desertification indexes, SDI and DI, are derived from the radiative transfer equation, and are employed with multi-channel measurements of the DMSP SSM/I for monitoring the sandstorm and desertification in northern China. Some SSM/I data in 1997 and 2001 are employed. The algorithm of Getis statistics is developed to categorize the spatial correlation and its evolution these days. It is demonstrated that the SSM/I indexes, SDI and DI, and its Getis statistics are well applicable for monitoring the sandstorm and desertification.     

Contributions of different land cover types in Otindag Sandy Land and Bashang area of Hebei Province to the material source of sand stormy weather in Beijing

Different land cover types in Otindag Sandy Land and Bashang area of Hebei Province are linked to a material source of sand stormy weather in Beijing based on results of field vegetation and soil survey and laboratory works. Results of grain size analysis show that dust release potential in per unit area of moving sandy land is small,while lowland meadow and meadow steppe in stony hills have high potential of releasing dusts in per unit area during sand stormy weather occurrence. Further considering the effects of vegetation, it is inferred that the moving sandy land served as a material source of past dust storm and the possibility of dust release in per unit area is low in current time.Typical steppe in stony hills is undergoing desertification and its dust release possibility in per unit area is high. Farmland has strong potential of release dusts when they are ploughed in spring, but a large amount of therophytes grow and thus prevent dusts from release when cultivation was terminated.Potentials of dust release in per unit area in fixed sand dunes,stony mountain meadow steppe and low land meadow are lowdue to high cover of perennials. Sand dune reactivation and desiccation of lakes and lowlands under estimated future climatic change will make them serve as a future material source of sand stormy weather.     

略论中国荒漠化的原因和防治对策

荒漠化已成为中国走向可持续发展的重大制约因素。人畜密度过大和贫困是造成我国荒漠化的两个根本原因，两者的相互作用引发了不合理的农垦、过度放牧、过度樵采、陡坡垦耕，以及水资源利用不当。因此，防治荒漠化的基本对策是控制人口增长和通过防治与开发并重来促进地方经济的发展，进而“富民”。文章提出了政策、科技、公众参与、管理、资金、国际合作等方面的１０条建议。     

喀斯特峡谷区不同等级石漠化土壤侵蚀对比研究——以贵州花江示范区为例

利用侵蚀线法、谷坝监测法对花江示范区的土壤侵蚀量作监测,同时就土壤侵蚀因子进行系统性、相关性和层次性研究,进行不同等级石漠化下的土壤侵蚀因子的对比,归纳各土壤侵蚀因子对土壤侵蚀的影响。结果指出林—草结构的保土保水能力优于单一林地的保土保水能力;从潜在石漠化到中度石漠化地区,土层根系量与侵蚀量呈负相关;从潜在、无明显、强度、轻度、直至中度石漠化,其侵蚀厚度依次增加,中度和轻度这两种等级的石漠化现存的土层较厚,土壤侵蚀模数也较大。     

半干旱区农牧交错带风水交互侵蚀特点研究——以内蒙古四子王旗南部为例

以内蒙古四于王旗南部为例，研究了半干旱区农牧交错带风水交互侵蚀的特点．结果表明，该地区低山丘陵与宽谷相间分布，坡地上有大量疏松的沉积物；夏季降水以暴雨为主，春秋季多大风，形成风水复合侵蚀发育．每年夏秋季节的水蚀为风蚀提供了大量的沙物质，第2年春季的大风将沙物质进一步吹扬扩散，为水蚀的搬运提供了物质基础，如此反复．使水系的上游形成沟谷，中下游沙化迅速．     

农村环境现状与发展有机农业的必要性分析

在中国农村生态环境的现状中,水土流失、荒漠化、草地退化、湿地减少等问题日益突出,农业综合开发的规模和乡镇工业对资源的利用强度加重了农村环境污染和生态的破坏,为此,必须重新审视我们的农业生产和生活方式,寻找合适的农业生产模式——发展有机农业。     

绿洲生态农业建设是新疆农业发展的必由之路

新疆的农业生产在近几年取得了巨大的成就，但由于水资源利用失调，土地沙漠化严重，化学制品污染及农业结构不合理等问题，导致生态环境恶化，农业面临着严峻的挑战。因此，建设绿洲生态农业成为新疆农业发展的必然选择。新疆绿洲生态农业建设应当以现代技术为核心，以人、水、土为支点，以外部生态环境治理相协调，构建新疆生态农业建设体系。     

荒漠化地区县级潜在土地利用冲突识别

选取荒漠化、土地利用冲突典型的宁夏盐池县为案例, 采用改进的LUCIS冲突识别模型, 构建基于建设、农业和生态用地倾向的3层潜在土地利用冲突评价指标体系, 借助冲突判别矩阵, 识别出4种潜在冲突类型区: 用地优势区、冲突微弱区、冲突一般区和冲突激烈区; 在此基础上, 又依据用地倾向强度级别组合, 细分为12种冲突类型。结果表明, 盐池县有58.90%的土地存在潜在土地利用冲突, 冲突等级以一般为主, 主要为建设用地与农业用地冲突、农业用地与生态用地冲突和三类用地的相互冲突; 有6.82%的区域发生冲突的风险性高, 主要为建设用地与农业用地间的冲突、农业用地与生态用地间的冲突; 另有40.88%的土地属于用地优势区。结合野外实际调研及近十年政策和制度研读, 对冲突的驱动因素进行分析, 并在利益相关者分析的基础上, 提出各类土地利用冲突的权衡策略。在生态脆弱地区建设、农业和生态3种类型用地潜在冲突识别及利益权衡方面进行了探索, 研究结果对维护荒漠化地区生态安全及社会经济可持续发展有现实意义。     

基于CA-ANN喀斯特石漠化时空格局的动态模拟和预测

分析了石漠化成灾综合机理,以GIS为平台,结合元胞自动机和神经网络模型,对石漠化灾害的空间格局进行动态模拟和预测.鉴于元胞自动机转换规则的难于确定的特点,利用神经网络来训练和获取石漠化转化的规则,进一步提高元胞自动机动态模拟能力.同时,由于GIS中嵌入元胞自动机,GIS的空间分析功能得到增强.