Development and analysis of spring plant phenology products: 36 years of 1-km grids over the conterminous US
Development and analysis of spring plant phenology products: 36 years of 1-km grids over the conterminous US
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DOI：
10.1016/j.agrformet.2018.06.028
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发表时间：
2018-11
影响因子：
6.2
通讯作者：
E. Izquierdo-Verdiguier;R. Zurita-Milla;T. Ault;M. D. Schwartz
中科院分区：
文献类型：
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作者：
E. Izquierdo-Verdiguier;R. Zurita-Milla;T. Ault;M. D. Schwartz
物候产品的时间序列提供了有关生物事件周期及其时间趋势的信息。这些信息对于研究气候变化对地球的影响以及管理自然资源和农业生产至关重要。在这里，我们开发和分析了新的长期物候产品：1980年至2015年美国境内扩展春季指数（SI-x）的1公里网格。这些新产品（基于Daymet每日温度网格，并使用云计算创建）允许分析两个主要变量（第一片叶子和第一次开花）和两个衍生产品（损害指数和上次冻结日），其空间分辨率比以前的网格或插值产品更精细。此外，我们的产品提供了足够的时间深度，可以可靠地分析大陆尺度上春季到来时间的趋势和变化。验证结果证实，我们的产品与紫丁香和金银花的叶子和开花开始观察结果基本一致。空间分析表明，显着延迟的春季发病在美国北方，而在西部和五大湖地区，春季发病的进步。的平均时间变化的指数进行了分析，为美国的9个主要气候区域，结果显示出明确的划分为三个主要群体：早期，平均和晚春开始。最后，映射属于每个组的区域。这些例子表明，我们的四个物候产品的潜力，以提高生态系统对气候变化的反应的理解。
Time series of phenological products provide information on the timings of recurrent biological events and on their temporal trends. This information is key to studying the impacts of climate change on our planet as well as for managing natural resources and agricultural production. Here we develop and analyze new long term phenological products: 1 km grids of the Extended Spring Indices (SI-x) over the conterminous United States from 1980 to 2015. These new products (based on Daymet daily temperature grids and created by using cloud computing) allow the analysis of two primary variables (first leaf and first bloom) and two derivative products (Damage Index and Last Freeze Day) at a much finer spatial resolution than previous gridded or interpolated products. Furthermore, our products provide enough temporal depth to reliably analyze trends and changes in the timing of spring arrival at continental scales. Validation results confirm that our products largely agree with lilac and honeysuckle leaf and flowering onset observations. The spatial analysis shows a significantly delayed spring onset in the northern US whereas in the western and the Great Lakes region, spring onset advances. The mean temporal variabilities of the indices were analyzed for the nine major climatic regions of the US and results showed a clear division into three main groups: early, average and late spring onset. Finally, the region belonging to each group was mapped. These examples show the potential of our four phenological products to improve understanding of the responses of ecosystems to a changing climate.