利用20012011年的MODIS EVI 时间序列影像,分析海南岛热带雨林、橡胶林及农田3种典型植被覆盖区的EVI 时空变化特征及对气象因子的响应。结果表明:(1)空间上,海南岛平均EVI 指数为0.42,呈现为中间高四周低,南高北低的分布特征;(2)时间上,热带雨林EVI年内变化幅度较小,无明显季节性变化,橡胶林年内季节性变化明显,冬末最低,春季快速增长,随后保持较高水平,农田变化幅度与周期性介于两者之间;3种典型植被年际EVI 最大值相对稳定,最小值波动较大,橡胶林最大值呈略增大趋势;(3)限制3种植被生长的气象因子不相同,农田受限于冬季日照;影响橡胶林最大的气象因子为年降水量与冬季气温,雨林喜好夏季高温而受制于冬季降水量。
英文摘要:
In this study, MODIS EVI time series image datasets of 2001- 2011were used to analyze EVI temporal and spatial variation characteristics of three kinds of typical vegetation zones, including tropical rainforest, rubber plantation and farmland, and explore the responses to meteorological factors. The results showed that: (1) from space point, the average EVI index of Hainan Island was 0.42, distributed as high in the middle while low in the surrounding, and high in the south while low in the north; (2) from time point, rainforest EVI changed less during the year, seasonal changes was not significant; in contrast, rubber plantation had obvious seasonal changes during the year, with the lowest EVI changes in late winter and rapid EVI growth during spring, then maintained at a high level; farmland had a moderate range of variation between the above two vegetations; annual EVI peak of the three typical vegetation areas was relatively stable, the least value varied greatly and the maximum annual EVI of rubber plantation presented a slightly increasing trend; (3) meteorological factors that limiting the three vegetation areas growth were different, the main limiting factor of farmland was winter sunshine, rubber plantation mostly was affected by whole year precipitation and winter temperatures, and rainforest was benefited by summer heat and influenced by dry winter.