Spatial and Temporal Changes in Vegetation Phenology at Middle and High Latitudes of the Northern Hemisphere over the Past Three Decades
Spatial and Temporal Changes in Vegetation Phenology at Middle and High Latitudes of the Northern Hemisphere over the Past Three Decades
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近三十年北半球中高纬度地区植被物候时空变化
DOI：
10.3390/rs70810973
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发表时间：
2015
期刊：
影响因子：
5
通讯作者：
Chen Chun
中科院分区：
文献类型：
--
作者：
Zhao Jianjun;Zhang Hongyan;Zhang Zhengxiang;Guo Xiaoyi;Li Xuedong;Chen Chun
植被物候是监测陆地生态系统和全球变化的重要生物学指标，植被物候变化最明显的地区主要位于高纬度和高海拔地区。近30年来，对北方中高纬度地区植被明显物候变化的研究为认识全球气候变化做出了重要贡献。利用全球植被指数（GIMMS）归一化差异植被指数（NDVI 3g）提取物候参数，分析1982-2013年北方半球40°N以上植被物候变化的时空特征。结果表明，在最初的21年（1982-2002）中，整个研究区域的季节开始（SOS）显著提前（-2.2 ± 0.6天·十年-1，p < 0.05），季节结束（EOS）略有延迟（0.78 ± 0.6天·十年-1，p = 0.21）。当时间尺度扩展到2013年时，SOS和EOS的变化率显著降低;此外，在过去11年（2003-2013年）中，整个研究区域的SOS延迟（3.2 ± 1.7天·十年-1，p <0.05），EOS提前（4.5 ± 0.9天·十年-1，p < 0.05）。在半球尺度上，过去30年的SOS提前和EOS延迟的趋势比最初20年的趋势要慢。不同植被类型的变化趋势有明显的差异，木本植物的变化趋势大于草本植物。对于阔叶林，从1982-2013年，SOS显著提前（2 ± 0.5天·十年-1，p < 0.05），EOS显著延迟（2.7 ± 0.6天·十年-1，p < 0.05）。不同植被类型的延迟EOS大于提前SOS的趋势。就北方半球物候趋势的空间分布而言，提前SOS和延迟EOS的趋势在欧洲最强，其次是北美，亚洲的趋势最不显著。针叶林、灌木林、草地和整个研究区在两个时间段（1982-2002年和2003-2013年）具有相同的变化趋势，近10年来物候参数的增加速率有所减缓。近32年来，阔叶林和混交林的季节长度均呈明显的增长趋势，同时，阔叶林的季节长度和混交林的季节长度分别呈提前和延迟的趋势
Vegetation phenology is a key biological indicator for monitoring terrestrial ecosystems and global change, and regions with the most obvious phenological changes in vegetation are primarily located at high latitudes and altitudes. Over the past three decades, investigations of obvious phenological changes in vegetation at middle and high latitudes in the Northern Hemisphere have provided significant contributions to understanding global climate change. In this study, phenological parameters were extracted from the Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) to analyze the spatial and temporal characteristics of vegetation phenological changes above 40°N in the Northern Hemisphere from 1982–2013. The results showed that the start of season (SOS) was significantly advanced (−2.2 ± 0.6 days·decade−1, p < 0.05) and that the end of season (EOS) was slightly delayed (0.78 ± 0.6 days·decade−1, p = 0.21) over the entire study area in the initial 21 years (1982–2002). When the time scale was extended to 2013, the change rate of the SOS and EOS was significantly reduced; in addition, the SOS was delayed (3.2 ± 1.7 days·decade−1, p < 0.05), and the EOS was advanced (4.5 ± 0.9 days·decade−1, p < 0.05) over the entire study area in the last 11 years (2003–2013). The trends of advanced SOS and delayed EOS over the past three decades were slower than those over the initial two decades on a hemispheric scale. The change trends showed obvious variability with different vegetation types and were greater for woody plants than for herbaceous plants. For broad-leaved forest, the SOS was significantly advanced (2 ± 0.5 days·decade−1, p < 0.05) and the EOS was significantly delayed (2.7 ± 0.6 days·decade−1, p < 0.05) from 1982–2013. The trend of delayed EOS was greater than that of advanced SOS for different vegetation types. With respect to the spatial distribution of phenological trends in the Northern Hemisphere, the trends of advanced SOS and delayed EOS were strongest in Europe followed by North America, and the trends were least significant in Asia. Coniferous forest, shrub forest, grassland, and the entire study area have the same change trends for the two time periods (1982–2002 and 2003–2013), and the increased rate of the phenology parameters has decelerated over the most recent decade. The length of season (LOS) of broad-leaved forest and mixed forest over the past 32 years shows a strong increased trend, and simultaneously, the SOS and EOS show an advanced trend and a delayed trend, respectively