Shifts in phenology are important traces of climate change affecting mountainous ecosystems. We present an analysis of changes in spring phenology using a suite of Earth observation based parameters, that is, start of season (SOS), snow cover extent and meteorological variables from 1991 up to 2012/2014 for the European Alps. Our results show that SOS tends to occur earlier throughout the Alps during this period and spring temperatures have increased in the Eastern Alps. Spring temperatures presented a predominant influence on SOS for both, grasslands and forests across elevations between 500 and 2,200 m asl, while this effect is particularly pronounced in the northeastern Alps. Snow cover duration and snow cover melting days showed secondary impact on SOS. Our research provides a comprehensive observation of spatiotemporal changes in alpine spring vegetation phenology and its driving factors. They improve our understanding of the sensitivity of the European Alps ecosystems to a changing climate.

中文翻译：

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春季温度和积雪气候推动了欧洲阿尔卑斯山的高级春季物候研究（1991–2014）

物候学的变化是影响山区生态系统的气候变化的重要痕迹。我们使用一套基于地球观测的参数，即欧洲阿尔卑斯山从1991年到2012/2014年的季节开始（SOS），积雪范围和气象变量，对春季物候变化进行了分析。我们的结果表明，在此期间，整个阿尔卑斯山的SOS趋于早期发生，东部阿尔卑斯山的春季温度升高。春季温度对海拔在500至2200 m asl之间的草地和森林的SOS均具有主要影响，而这种影响在东北阿尔卑斯山尤为明显。积雪持续时间和积雪融化天数对SOS产生了次要影响。我们的研究提供了对高山春季植被物候时空变化及其驱动因素的全面观察。他们增进了我们对欧洲阿尔卑斯山生态系统对气候变化敏感性的理解。