Cong Nan, Shen Miao Gen
Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
Ying Yong Sheng Tai Xue Bao. 2016 Sep;27(9):2737-2746. doi: 10.13287/j.1001-9332.201609.028.
In-depth understanding the variation of vegetation spring phenology is important and nece-ssary for estimation and prediction of ecosystem response to climate change. Satellite-based estimation is one of the important methods for detecting the vegetation spring phenology in Northern Hemisphere. However, there are still many uncertainties among different remote sensing models. In this study, we employed NDVI satellite product from 1982 to 2009 to estimate vegetation green-up onset dates in spring across Northern Hemisphere, and further analyzed the phenology spatio-temporal variation and the relationship with climate. Results showed that spatial mean spring phenology significantly advanced by (4.0±0.8) days during this period in the Northern Hemisphere, while spring phenology advanced much faster in Eurasia (0.22±0.04 d·a) than in North America (0.03±0.02 d·a). Moreover, phenology of different vegetation types changed inconstantly during the period. All five methods consistently indicated that grassland significantly advanced, while forests didn't advance robustly among methods. In addition, the interannual change of spring phenology was mainly driven by spring temperature. The spring phenology advanced (3.2±0.5) days with 1 ℃ increase in temperature. On the contrary, we did not find significant relationship between vegetation spring phenology and spring accumulative precipitation across the Northern Hemisphere (P>0.05) in this study.
深入了解植被春季物候变化对于评估和预测生态系统对气候变化的响应至关重要且必不可少。基于卫星的估算是检测北半球植被春季物候的重要方法之一。然而，不同的遥感模型之间仍存在许多不确定性。在本研究中，我们利用1982年至2009年的归一化植被指数（NDVI）卫星产品来估算北半球春季植被返青开始日期，并进一步分析了物候的时空变化及其与气候的关系。结果表明，在此期间北半球空间平均春季物候显著提前了(4.0±0.8)天，而欧亚大陆（0.22±0.04天·年）的春季物候比北美（0.03±0.02天·年）提前得更快。此外，在此期间不同植被类型的物候变化并不一致。所有五种方法均一致表明草地显著提前，而森林在各方法中提前并不显著。另外，春季物候的年际变化主要受春季温度驱动。温度每升高1℃，春季物候提前(3.2±0.5)天。相反，在本研究中我们未发现北半球植被春季物候与春季累积降水量之间存在显著关系（P>0.05）。
