This article analyzes the large-scale circulations producing daily precipitation extremes in the Southwestern Alps and their trends from 1958 to 2017. We consider a high-resolution precipitation data set of 1 1 km² and the weather patterns associated to the precipitation seasonal maxima at each grid point. The high-resolution allows us to analyze in details the atmospheric influences triggering seasonal maxima. Four influences are considered—the Atlantic influence, the Mediterranean influence, the northeast circulation and the Anticyclonic situation. We show that influences on maxima are very well organized in space but their organization depends on the season. Maxima are very mainly triggered by two types of influences in the region—the Atlantic influence and the Mediterranean influence. Trends in weather patterns producing maxima are also organized in space, with opposite trends for the Atlantic and the Mediterranean influences. The Mediterranean influence retreated very significantly over the period in winter and spring, while the Atlantic influence significantly extended further south. In autumn the Mediterranean influence strengthened where it was already dominant.

本文分析了西南阿尔卑斯山每天产生极端降水的大规模环流及其1958年至2017年的趋势。我们考虑了1 1 km ²的高分辨率降水数据集以及与每个网格点处的降水季节最大值相关的天气模式。高分辨率使我们能够详细分析触发​​季节最大值的大气影响。考虑了四种影响-大西洋影响，地中海影响，东北环流和反气旋形势。我们表明，对最大值的影响在空间上组织得很好，但它们的组织取决于季节。千里马非常主要地受到该地区两种类型的影响的触发-大西洋影响和地中海影响。产生最大值的天气模式趋势也在空间中组织，而大西洋和地中海的影响则相反。在冬季和春季，地中海的影响力显着下降，而大西洋的影响力进一步向南延伸。在秋天，地中海的影响力在已经占主导地位的地方增强了。