Landscape ecology emphasizes large areas and ecological effects of the spatial patterning of ecosystem. Recent developments in landscape ecology have emphasized the important relationship between spatial patterns and ...Landscape ecology emphasizes large areas and ecological effects of the spatial patterning of ecosystem. Recent developments in landscape ecology have emphasized the important relationship between spatial patterns and many ecological processes. Quantitative methods in landscape ecology link spatial patterns and ecological processes at broad spatial and temporal scales. In turn the increased attention on temporal change of ecosystem has highlighted the need for quantitative methods that can analyze patterns. This research applies quantitative methods——change detection to assess the ecosystem temporal change in the arid and semiarid area. Remote sensing offers the temporal change of ecosystem on landscape characteristics.展开更多
黄河上游宁夏-内蒙古段穿越河东沙地、乌兰布和沙漠和库布奇沙漠,大量风沙被吹入黄河,因此,迫切需要揭示宁夏-内蒙古河段沙粒起动风速的空间分布规律,从而为该区域的风沙防治工作提供理论依据。首先,应用归一化植被指数(normalized diff...黄河上游宁夏-内蒙古段穿越河东沙地、乌兰布和沙漠和库布奇沙漠,大量风沙被吹入黄河,因此,迫切需要揭示宁夏-内蒙古河段沙粒起动风速的空间分布规律,从而为该区域的风沙防治工作提供理论依据。首先,应用归一化植被指数(normalized different vegetation index,NDVI)数据集计算该河段地表植被盖度、植被迎风面积指数与粗糙度。而后,通过植被迎风面积指数计算摩阻起动风速的影响函数,研究河段摩阻起动风速的空间分布。利用实测数据检验摩阻起动风速的计算方法,表明摩阻起动风速的计算方法误差较小。研究表明,研究区内风速廓线均呈对数函数的分布规律,并利用风速廓线方程计算了研究区不同下垫面(10m高度)处的起动风速,进而得到跃移沙粒起动风速的空间分布。结果显示研究区风蚀风险最大的几个区域大多临近黄河。最后,根据当年最大NDVI值与下一年风季(3月至5月)NDVI平均值之间的关系,提出利用当年最大NDVI值对下一年风季起动风速的预测方法,该研究为黄河宁夏-内蒙古段的风蚀预报提供理论支撑。展开更多
文摘Landscape ecology emphasizes large areas and ecological effects of the spatial patterning of ecosystem. Recent developments in landscape ecology have emphasized the important relationship between spatial patterns and many ecological processes. Quantitative methods in landscape ecology link spatial patterns and ecological processes at broad spatial and temporal scales. In turn the increased attention on temporal change of ecosystem has highlighted the need for quantitative methods that can analyze patterns. This research applies quantitative methods——change detection to assess the ecosystem temporal change in the arid and semiarid area. Remote sensing offers the temporal change of ecosystem on landscape characteristics.
文摘黄河上游宁夏-内蒙古段穿越河东沙地、乌兰布和沙漠和库布奇沙漠,大量风沙被吹入黄河,因此,迫切需要揭示宁夏-内蒙古河段沙粒起动风速的空间分布规律,从而为该区域的风沙防治工作提供理论依据。首先,应用归一化植被指数(normalized different vegetation index,NDVI)数据集计算该河段地表植被盖度、植被迎风面积指数与粗糙度。而后,通过植被迎风面积指数计算摩阻起动风速的影响函数,研究河段摩阻起动风速的空间分布。利用实测数据检验摩阻起动风速的计算方法,表明摩阻起动风速的计算方法误差较小。研究表明,研究区内风速廓线均呈对数函数的分布规律,并利用风速廓线方程计算了研究区不同下垫面(10m高度)处的起动风速,进而得到跃移沙粒起动风速的空间分布。结果显示研究区风蚀风险最大的几个区域大多临近黄河。最后,根据当年最大NDVI值与下一年风季(3月至5月)NDVI平均值之间的关系,提出利用当年最大NDVI值对下一年风季起动风速的预测方法,该研究为黄河宁夏-内蒙古段的风蚀预报提供理论支撑。
