BACKGROUND Changes in land surface phenology are of major importance to the understanding of the impact of recent and future climate changes in the Arctic. This paper presents an extensive study from Zackenberg Ecological Research Operations (ZERO) where snow melt, climate and growing season characteristics of six major high arctic vegetation types has been monitored during 1999 to 2005. We investigate the growth dynamics for dry, mesic and wet types using hand held measurements of far red normalised difference vegetation index (NDVI-FR) and generalized additive mixed models (GAMM). RESULTS Snow melt and temperature are of major importance for the timing of the maximum growth as well as for the seasonal growth. More than 85% of the variance in timing of the maximum growth is explained by the models and similar for the seasonal growth of mesic and wet vegetation types. We find several non-linear growth responses to the environmental variables. CONCLUSION We conclude that the uses of GAMMs are valuable for investigating growth dynamics in the Arctic. Contrary to several other studies in the Arctic we found a significant decreasing trend of the seasonally integrated NDVI-FR (SINDVI) in some vegetation types. This indicates that although greening might occur wide-spread in the Arctic there are variations on the local scale that might influence the regional trends on the longer term.

中文翻译：

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光谱测量和混合模型是调查北极高地格陵兰岛地表物候控制方面的重要工具。

背景技术地表物候的变化对于了解北极地区近期和未来气候变化的影响至关重要。本文对Zackenberg生态研究中心（ZERO）进行了广泛的研究，该研究对1999年至2005年期间六种主要的高北极植被类型的融雪，气候和生长期特征进行了监测。使用远红色归一化植被指数（NDVI-FR）和广义加性混合模型（GAMM）的手持测量。结果融雪和温度对于最大生长的时间以及季节性生长至关重要。模型解释了最大生长时间变化中超过85％的变化，并且对于中，湿植被类型的季节性增长也是如此。我们发现一些对环境变量的非线性增长响应。结论我们得出结论，GAMMs的使用对于研究北极地区的生长动力非常有价值。与北极地区的其他一些研究相反，我们发现某些植被类型的季节性综合NDVI-FR（SINDVI）呈明显下降趋势。这表明，尽管北极地区的绿化可能广泛发生，但局部范围的变化可能会长期影响区域趋势。结论我们得出结论，GAMMs的使用对于研究北极地区的生长动力非常有价值。与北极地区的其他一些研究相反，我们发现某些植被类型的季节性综合NDVI-FR（SINDVI）呈明显下降趋势。这表明，尽管北极地区的绿化可能广泛发生，但局部范围的变化可能会长期影响区域趋势。结论我们得出结论，GAMMs的使用对于研究北极地区的生长动力非常有价值。与北极地区的其他一些研究相反，我们发现某些植被类型的季节性综合NDVI-FR（SINDVI）呈明显下降趋势。这表明，尽管北极地区的绿化可能广泛发生，但局部范围的变化可能会长期影响区域趋势。