ABSTRACT Intermittent rivers are prevalent in many countries across Europe, but little is known about the temporal evolution of intermittence and its relationship with climate variability. Trend analysis of the annual and seasonal number of zero-flow days, the maximum duration of dry spells and the mean date of the zero-flow events is performed on a database of 452 rivers with varying degrees of intermittence between 1970 and 2010. The relationships between flow intermittence and climate are investigated using the standardized precipitation evapotranspiration index (SPEI) and climate indices describing large-scale atmospheric circulation. The results indicate a strong spatial variability of the seasonal patterns of intermittence and the annual and seasonal number of zero-flow days, highlighting the controls exerted by local catchment properties. Most of the detected trends indicate an increasing number of zero-flow days, which also tend to occur earlier in the year, particularly in southern Europe. The SPEI is found to be strongly related to the annual and seasonal zero-flow day occurrence in more than half of the stations for different accumulation times between 12 and 24 months. Conversely, there is a weaker dependence of river intermittence with large-scale circulation indices. Overall, these results suggest increased water stress in intermittent rivers that may affect their biota and biochemistry and also reduce available water resources.

中文翻译：

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欧洲河流断流趋势

摘要 间歇性河流在欧洲的许多国家都很普遍，但对间歇性的时间演变及其与气候变率的关系知之甚少。对 1970 年至 2010 年间 452 条不同程度间歇河流的数据库进行了年度和季节性零流量天数、最大旱期和零流量事件平均日期的趋势分析。使用标准化降水蒸散指数 (SPEI) 和描述大尺度大气环流的气候指数来研究流量间歇与气候之间的关系。结果表明，间歇性季节性模式以及年度和季节性零流量天数的空间变异性很强，突出了当地集水区特性所施加的控制。大多数检测到的趋势表明零流量日数不断增加，而且往往发生在今年早些时候，尤其是在南欧。发现 SPEI 与 12 至 24 个月之间不同累积时间的一半以上站点的年度和季节性零流量日发生密切相关。相反，大尺度环流指数对河流间歇性的依赖性较弱。总体而言，这些结果表明间歇性河流的水资源压力增加，可能会影响其生物群和生物化学，并减少可用水资源。发现 SPEI 与 12 至 24 个月之间不同累积时间的一半以上站点的年度和季节性零流量日发生密切相关。相反，大尺度环流指数对河流间歇性的依赖性较弱。总体而言，这些结果表明间歇性河流的水资源压力增加，可能会影响其生物群和生物化学，并减少可用水资源。发现 SPEI 与 12 至 24 个月之间不同累积时间的一半以上站点的年度和季节性零流量日发生密切相关。相反，大尺度环流指数对河流间歇性的依赖性较弱。总体而言，这些结果表明间歇性河流的水资源压力增加，可能会影响其生物群和生物化学，并减少可用水资源。