This study presents data from the first years of permafrost monitoring in boreholes in the French Alps that started at the end of 2009 in the framework of the PermaFrance network. Nine boreholes are instrumented, among which six monitored permafrost temperature and active layer thickness (ALT) over >10 years. Ice-poor and cold permafrost in high-elevation north-facing rock walls has warmed by up to >1°C at 10 m depth over the reference decade (2011–2020), whereas ice-rich permafrost (rock glacier) temperatures remained stable. ALT has increased at four of the five boreholes for which decadal data are available. Summer 2015 marks a turning point in ALT regime and greatest ALT values were observed in 2022 (available for six boreholes), but thawing intensity did not show an obvious change. At one site with a layer of coarse blocks about 2 m thick, ALT was stable over 2018–2022 and response to the hottest years was dampened. Linear trends suggest an ALT increase of 2 m per decade for some ice-poor rock walls, independently of their thermal state. The data reveal a variety of permafrost patterns and evolution with significant intraregional and local differences. Snow modulates the response to air temperature signal in various ways, with an important effect on near-surface temperature trends and ALT: early snow melting in spring favors an ALT increase in rock walls. Maintaining these monitoring systems and understanding the physical processes controlling heterogeneous responses to climate signals is crucial to better assess permafrost dynamics and to adapt to its consequences.

中文翻译：

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2010-2022 年期间通过 PermaFrance 网络对法国阿尔卑斯山永久冻土进行监测的主要结果

本研究提供了 2009 年底在 PermaFrance 网络框架内开始的法国阿尔卑斯山钻孔永久冻土监测第一年的数据。九个钻孔安装了仪器，其中六个钻孔监测了超过 10 年的永久冻土温度和活性层厚度 (ALT)。在参考十年（2011-2020）中，高海拔北向岩壁中10 m深度的贫冰和寒冷永久冻土温度升高了>1°C，而富含冰的永久冻土（岩石冰川）温度保持稳定。在可获得十年数据的五个钻孔中，有四个钻孔的 ALT 有所增加。2015 年夏季标志着 ALT 状况的转折点，并在 2022 年观察到最大 ALT 值（可用于六个钻孔），但解冻强度没有显示出明显的变化。在一个具有约 2 m 厚的粗块层的地点，ALT 在 2018 年至 2022 年期间保持稳定，对最热年份的响应受到抑制。线性趋势表明，对于一些贫冰岩壁，ALT 每十年增加 2 m，与其热状态无关。这些数据揭示了各种永久冻土模式和演化，具有显着的区域内和局部差异。雪以多种方式调节对气温信号的响应，对近地表温度趋势和 ALT 产生重要影响：春季早期融雪有利于岩壁 ALT 的增加。维护这些监测系统并了解控制对气候信号的异质响应的物理过程对于更好地评估永久冻土动态并适应其后果至关重要。