[初二地理小论文]
摘要: 风沙是一种以气候为主因的灾害类型,大风是形成风沙的主要因素。地形、降水、气温和沙源也是促成风沙危害的发生发展的重要因素。针对不同的沙化土地分布特征划分治理区域,通过对其风沙危害季节的风沙扩散情况进行科学分析、正确评估,统筹设计治理方案, 构建防沙治沙的安全格局,能有效地阻止风沙漫延,切断其扩散路径,降低风沙灾害的危害程度。 Abstract: Sandstorm is mainly a result of climate, which origin is wind. Topography, precipitation, temperature and sand resources also contribute to the development of sandstorm hazards. Zoning control on distribution of different desertified land area, scientific analysis and correct assessment of sand spread at the sandstorm season and overall design of governance program, building of security patterns of sand prevention and control can effectively prevent the spread of sand, cut off the diffusion path, and reduce harmful levels of sandstorm disasters. 关键词: 风沙灾害;防沙治沙;安全格局 Key words: sandstorm disaster; prevention and control of desertification; security patterns
1 风沙灾害的危险性分析 1.1 风沙成因及扩散要素分析 1.1.1 气候、风速、风向、空间距离 季节性差异和年际、年内降雨量分布不均及降水量不足,会使地表因水蒸发量较大而土壤干燥。尤其是降水量较低且大风频发的冬春两季,裸露的农田因严重风蚀,致使干燥的土壤在大风的作用下发生起沙、扬沙甚至沙尘暴,形成风沙灾害;风速大时沙尘……
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