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植物叶物候是反映环境条件对气候变化响应的最直观、最敏感的指标之一。在中亚干旱区开展区域物候研究有助于理解陆地生态系统对气候变化的响应。基于1982-2006年GIMMS长序列归一化植被指数数据,采用阈值法反演得到中亚地区植被过去25 a的物候数据集;然后利用Man-Kendall趋势检验和TheilSen斜率方法,定量分析了中亚地区植被物候的时空变化格局,并且评价了不同土地覆被类型中植被物候变化的特征。结果表明:(1)过去25 a来,中亚干旱区的植被生长季的开始期和终止期在区域尺度整体上没有发生显著提前或者延迟,但在局部地区发生了较为明显的变化,表现出一定的空间差异;(2)各种土地覆被类型的物候动态明显不同:农用地的生长季开始期提前最明显,混合林的生长季终止期推迟最显著。各种植被类型中,除灌丛外均表现出生长期延长的趋势。
Plant leaf phenology is one of the most intuitive and sensitive indicators reflecting the response of environmental conditions to climate change. Conducting regional phenological studies in arid zones of Central Asia can help to understand the response of terrestrial ecosystems to climate change. Based on the GIMMS long sequence normalized vegetation index data from 1982 to 2006, the phenological data set of the past 25 years in central Asia was obtained by the threshold method inversion. Then the Man-Kendall trend test and the TheilSen slope method were used to quantitatively analyze the data of Central Asia The temporal and spatial pattern of regional vegetation phenology, and evaluated the characteristics of vegetation phenology in different land cover types. The results show that: (1) The beginning and termination periods of the vegetation growth season in the arid region of Central Asia have not significantly advanced or retarded in the whole region in the past 25 years, but have obviously changed in some areas, (2) The phenological changes of different land cover types are obviously different: the start of the growing season of agricultural land is the most obvious, and the ending of the growing season of the mixed forest is the most significant. Among the various vegetation types, except the shrubs, the growth period was prolonged.