Finnish lake acidification survey: Survey design and random selection of lakes
Finnish lake acidification survey: Survey design and random selection of lakes
复制标题
芬兰湖泊酸化调查：调查设计和湖泊随机选择
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
M. Verta
中科院分区：
文献类型：
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作者：
M. Forsius;V. Malin;I. Mäkinen;J. Kämäri;P. Kortelainen;M. Verta
1987年秋天，作为芬兰酸化研究项目（HAPRO）的一部分，对1，189个湖泊进行了调查。调查的大多数湖泊（n=987）是从两个不同的分区域通过两阶段整群抽样随机选择的，覆盖了整个国家。在南部和中部区域（第1次区域）的统计抽样中包括了面积为0.01-10平方公里的湖泊。在芬兰北方（第2次区域），仅包括面积为0.1-10平方公里的湖泊。每个分区域的统计抽样“框架”由一系列比例尺为1：50 000（20 X30平方公里）的地形图组成的网格网中的湖泊数目组成。第1次区域的地图总数为472份，第2次区域为175份。在第一采样阶段，使用“与大小成比例的概率（pps）”方法从子区域1中选择了100张地图，从子区域2中选择了25张地图，地图的选择根据湖泊密度进行加权。在第二个取样阶段，对所有大小在确定的大小范围内的湖泊进行编号，并通过系统随机抽样从先前选定的每个地图中选出8个湖泊。另外还包括在以前的酸化研究中检查的202个主要是头水湖泊。在1987年秋季翻覆期间，从湖泊表层（1 m）采集水样。对每个湖水样品进行了广泛的分析。主要的分水岭特征已确定从地形图和土壤图。以统计为基础的调查设计允许对满足任何预定标准的湖泊比例和相应的方差进行估计。芬兰的酸性（酸中和能力（ANC）<0 μeq L-1）湖泊数量估计为4，900个。
A survey of 1,189 lakes was conducted in the fall of 1987 as part of the Finnish Research Project on Acidification (HAPRO). Most of the lakes for the survey (n=987) were randomly selected by a two-stage cluster sampling from two separate subregions, together covering the whole country. Lakes of sizes 0.01-10 km2 were included in the statistical sampling of the southern and central regions (Subregion 1). In northern Finland (Subregion 2) only lakes of sizes 0.1-10 km2 were included. The statistical sampling “frame” in each subregion consisted of the number of lakes in the grid net formed from a series of topographic maps with a scale of 1:50,000 (20X30 km2). The total number of maps was 472 in Subregion 1 and 175 in Subregion 2. In the first sampling stage, 100 maps were selected from Subregion 1 and 25 maps from Subregion 2, using the “probability proportional to size (pps)” method, selection of the maps being weighted by lake density. In the second sampling stage, all of the lakes with a size within the determined size range were numbered and eight lakes chosen by systematic random sampling from each previously selected map. A further 202 mainly head water lakes examined in previous acidification studies were also included. Water samples were taken from the surface layer (1m) of the lakes during fall overturn in 1987. An extensive analytical program was carried out on each lake-water sample. Major watershed characteristics have been determined from topographic and soil maps. The statistically based survey design allows estimates to be made of the proportion of lakes fulfilling any predetermined criteria and the corresponding variances. The number of acidic (acid neutralizing capacity (ANC) ⩽ 0 μeq L-1) lakes in Finland was estimated to be 4,900.