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天山北麓地下水与自然植被的空间变异及其分形特征 被引量:18
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作者 苏里坦 宋郁东 张展羽 《山地学报》 CSCD 北大核心 2005年第1期14-20,共7页
对面积约670km2的具有干旱气候特征的新疆三工河流域地下水埋深和自然植被盖度进行取样检测,应用地质统计学方法对取得数据进行半方差函数分析,计算均值、方差、标准差、变异系数等传统统计特征值,指出用该方法表示地下水埋深和自然植... 对面积约670km2的具有干旱气候特征的新疆三工河流域地下水埋深和自然植被盖度进行取样检测,应用地质统计学方法对取得数据进行半方差函数分析,计算均值、方差、标准差、变异系数等传统统计特征值,指出用该方法表示地下水埋深和自然植被盖度引起的困惑。在此基础上,将分形理论与地质统计学原理相结合,计算了三工河流域地下水埋深和自然植被盖度的分形维数,分别为1 3154、1 3677;而它们的变异系数分别为0 537、0 368。该地区地下水埋深和自然植被盖度在空间上存在显著的变异性,而且它们具有相似的变异特征,即随着地下水埋深的递增(或递减),自然植被盖度有所减少(或增加),说明干旱区自然植被盖度对地下水埋深有很大的依赖性。这暗示着在干旱地区影响自然植被盖度的众多因素中最具有决定性的因素是地下水埋深。 展开更多
关键词 天山北麓 地下水埋深 自然植被盖度 半方差函数 空间变异 分维
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The Relationship between Meteorological Variables and Clearness Index for Four Urban/Suburban Areas of Brazilian Cities
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作者 Francisco Jose Duarte Gomes Luciana Sanches +3 位作者 Marcelo de Carvalho Alves Marta Cristina de Jesus Albuquerque Nogueira Jose de Souza Nogueira 《Journal of Environmental Science and Engineering(B)》 2012年第7期890-900,共11页
This study aimed to examine the relationship between meteorological variables and the clearness index for three sites in Cuiaba city and one site in Chapada dos Guimaraes city, Brazil during 2007. It described the mic... This study aimed to examine the relationship between meteorological variables and the clearness index for three sites in Cuiaba city and one site in Chapada dos Guimaraes city, Brazil during 2007. It described the microclimate of each site on the basis of constructive elements and their surroundings, considering sky coverage using a daily clearness index. The results were that micrometeorological values were influenced by the natural elements and construction within the surrounding site, with higher air temperatures in more urbanized areas and sites with high diffuse radiation. When determining the sky coverage, on average, the days were partly cloudy or cloudy due to two reasons: (a) during the wet season, rainfall created cloudy conditions and (b) during the dry season, increases of particulates in the atmosphere as a result of anthropogenic emissions of gases and aerosols in this region of the state resulted in sky conditions classified as partly cloudy and cloudy. Future research should aim to better quantify the measurements taken inside an urban area, considering the topography and vegetation cover. This will improve the models that support urban planning, therefore favoring the thermal comfort of areas already occupied or to be urbanized. 展开更多
关键词 Tropical climate urban climate cover sky microclimate.
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