中亚及中国新疆干旱区植被物候时空变化

基于1982-2006年GIMMS（Global Inventory Modeling and Mapping Studies）长序列归一化植被指数数据，采用比例阈值法反演得到中亚及新疆地区植被过去25年的物候数据集；采用M-K趋势检验和Theil Sen斜率方法，分析植物生长季开始期、停止期和生长季长度的变化趋势，并结合历史土地利用数据和DEM数据评价不同植被覆盖类型和不同高程下的植被物候变化特征。结果表明：1982-2006年，中亚及中国新疆干旱区植被生长季开始期和停止期在区域尺度上没有显著提前或者延迟，但在局部地区变化明显，且空间差异较大。各植被覆盖类型的物候动态表现不同，农用地的生长季开始期提前最明显；落叶阔叶林等木本植被类型的生长季停止期以推迟为主，但其面积比例很小，影响十分有限；除灌丛和裸地外，其他类型均表现出生长季长度延长的趋势，但整个研究区植物生长季长度变化并不明显。不同高程下植被物候变化同样存在差异，区域气候变化改变了不同高程带的环境限制因子，继而对植被物候产生影响，特别是在2000～3000 m高程带，植被生长季开始期提前、停止期推迟和生长季长度延长更加明显。

Spatial-Temporal Change of Vegetation Phenology in Arid Zone of Central Asia and Xinjiang,China

Based on GIMMS (Global Inventory Modeling and Mapping Studies) data from 1982 to 2006, we calculated the vegetation phenological data in arid zone of Central Asia and Xinjiang, China using threshold method with the Timesat software. The Mann-Kendall trend analysis and Theil Sen slope tools were used to assess the spatial-temporal change. Combined with land cover data and digital elevation model, varieties of phenological metrics were also analyzed for different vegetation cover types and different elevation zones. According to our results, no significant phenological change was detected for the whole study area, but obvious change was found in some local areas. The area where the start of growth season (SOS) had advanced was also found to have a significant extended length of growth season (LOS). Different vegetation cover types showed remarkably different patterns in phonological changes. The end of growth season (EOS) of Deciduous Broadleaf Forest delayed significantly. Except for the Open Shrub, Closed Shrub and Bare Ground, most vegetation cover types showed an extended LOS. The phenology in different elevation varied obviously. Analyses further showed that the water and heat conditions in the 2000-3000 m elevation zone were improved, which may result in the most advanced SOS, delayed EOS and prolonged LOS in this zone.