Abstract Changes in Canadian Prairie streamflow, particularly trends over time, have not been well studied but are particularly relevant for food and water security in this vast agricultural region. Streamflow records for this region are often unsuitable for conventional trend analysis; streams are often intermittent and have only a few days per year with flow, and stations operate only during the warm season, because of a lack of flow during the very cold Prairie winter. This study takes an alternative approach; streamflow data for the period from March to October for individual years between 1910 and 2015 from 169 hydrometric stations from the Prairie and adjacent areas in Canada were converted to annual cumulative runoff series. These 5895 individual station-years were then clustered based upon their shape, using dynamic time warping. Three clusters of cumulative annual runoff were found; the first and most common type has infrequent days with flow and low total annual runoff [0–50 mm], the second has more days with flow and slightly greater runoff [48–175 mm], and the least common third type has the fewest days without flow, includes perennial streams, and has much greater annual runoff [>173 mm]. For each hydrometric station a time series of annual cluster memberships was created. Trends in the fractions of cluster types were determined using logistic regression, with spatial groupings of these time series over five-year periods. Trends in the fractions of types within an ecoregion indicate spatially consistent and organized changes in the pattern of runoff over the region. In the western Canadian Prairies, particularly in the Mixed Grassland and Cypress Upland ecoregions, drying is occurring, as indicated by the increased frequency of the dry type. In the northern and eastern Canadian Prairies, conditions are shifting to greater runoffs, particularly in the Aspen Parkland, where the wet types are increasing in frequency.

中文翻译：

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使用替代趋势评估方法的加拿大草原溪流时间变化的空间模式

摘要 加拿大草原径流的变化，尤其是随时间推移的趋势，尚未得到很好的研究，但与这个广阔农业区的粮食和水安全特别相关。该地区的流量记录通常不适用于传统的趋势分析；溪流通常是断断续续的，每年只有几天有水流，而且车站只在温暖的季节运行，因为在非常寒冷的草原冬季缺乏水流。这项研究采用了另一种方法；来自加拿大草原和邻近地区的 169 个水文站的 1910 年至 2015 年个别年份 3 月至 10 月期间的流量数据转换为年度累积径流序列。然后使用动态时间扭曲根据它们的形状将这 5895 个单独的站年聚类。发现了三个累积年径流集群；第一种也是最常见的类型，流量天数稀少，年径流总量低 [0-50 毫米]，第二种有流量天数更多，径流略大 [48-175 毫米]，最不常见的第三种类型最少无流量天数，包括多年生溪流，年径流量大得多 [>173 毫米]。对于每个水文站，创建了年度集群成员的时间序列。聚类类型分数的趋势使用逻辑回归确定，这些时间序列在五年期间的空间分组。一个生态区内类型比例的趋势表明该地区径流模式在空间上一致和有组织的变化。在加拿大西部大草原，特别是在混合草原和柏树高地生态区，干燥正在发生，如干燥类型的频率增加所示。在加拿大北部和东部大草原，条件正在转向更大的径流，特别是在阿斯彭帕克兰，湿型的频率正在增加。