Abstract. Plant phenology plays a fundamental role in land-atmosphere interactions, and its variability and variations are an indicator of climate and environmental changes. For this reason, current land surface models include phenology parameterizations and related biophysical and biogeochemical processes. In this work, the climatology of beginning and end of the growing season, simulated by seven state-of-the-art European land surface models, is evaluated globally against satellite observations. The assessment is performed using the vegetation metric leaf area index and a recently-developed approach, named four growing season types. On average, the land surface models show a 0.6-month delay in the growing season start, while they are about 0.5 months earlier in the growing season end. Difference with observation tends to be higher in the Southern Hemisphere compared to the Northern Hemisphere. High agreement between land surface models and observations is exhibited in areas dominated by broad-leaf deciduous trees, while high variability is noted in regions dominated by broad-leaf deciduous shrubs. Generally, the timing of the growing season end is accurately simulated in about 25 % of global land grid points versus 16 % in the timing of growing season start. The refinement of phenology parameterization can lead to better representation of vegetation-related energy, water, and carbon cycles in land surface models, but plant phenology is also affected by plant physiology and soil hydrology processes. Consequently, phenology representation and, in general, vegetation modelling is a complex task, which still needs further improvement, evaluation, and multi-model comparison.

中文翻译：

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CRESCENDO地表模型的植物物候学评估-第一部分：生长期的开始和结束

摘要。植物物候学在土地-大气相互作用中起着基本作用，其变异性和变异性是气候和环境变化的指标。因此，当前的陆地表面模型包括物候参数化以及相关的生物物理和生物地球化学过程。在这项工作中，将通过七个最新的欧洲陆地表面模型来模拟生长季节开始和结束的气候，并根据卫星观测对全球进行评估。使用植被度量的叶面积指数和最近开发的方法（称为四种生长季节类型）进行评估。平均而言，地表模型显示生长期开始延迟0.6个月，而生长期结束则提前0.5个月。与北半球相比，南半球的观测差异往往更大。在以阔叶落叶乔木为主的地区，陆地表面模型与观测值之间具有高度一致性，而在以阔叶落叶灌木为主的地区则表现出较高的变异性。通常，在全球陆地网格点的约25％中准确地模拟了生长季节结束的时间，而在生长季节开始的时间中精确地模拟了16％。物候参数化的完善可以导致在土地表面模型中更好地表示与植被相关的能量，水和碳循环，但是植物物候还受到植物生理学和土壤水文学过程的影响。因此，物候表征以及一般而言的植被建模是一项复杂的任务，