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Multilevel Assessment of Spatiotemporal Variability of Vegetation in Subtropical Mountain-hill Region
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作者 QIU Bing-wen ZENG Can-ying TANG Zheng-hong 《Journal of Mountain Science》 SCIE CSCD 2013年第6期1028-1038,共11页
The complex spatiotemporal vegetation variability in the subtropical mountain-hill region was investigated through a multi-level modeling framework. Three levels- parcel, landscape, and river basin levels- were select... The complex spatiotemporal vegetation variability in the subtropical mountain-hill region was investigated through a multi-level modeling framework. Three levels- parcel, landscape, and river basin levels- were selected to discover the complex spatiotemporal vegetation variability induced by climatic, geomorphic and anthropogenic processes at different levels. The wavelet transform method was adopted to construct the annual maximum Enhanced Vegetation Index and the amplitude of the annual phenological cycle based on the 16-day time series of250m Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index datasets during 2001-2010. Results revealed that land use strongly influenced the overall vegetation greenness and magnitude of phenological cycles.Topographic variables also contributed considerably to the models, reflecting the positive influence from altitude and slope. Additionally, climate factors played an important role: precipitation had a considerable positive association with the vegetation greenness, whereas the temperature difference had strong positive influence on the magnitude of vegetation phenology. The multilevel approach leads to a better understanding of the complex interaction of the hierarchical ecosystem, human activities and climate change. 展开更多
关键词 山地丘陵地区 植被变化 时空变异 多级 中分辨率成像光谱仪 评估 植物物候 植被指数
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基本养老保险与居民消费——基于CHARLS数据的多层次线性回归分析 被引量:17
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作者 赵青 李珍 《财政研究》 CSSCI 北大核心 2018年第3期87-98,共12页
养老保险与居民消费(储蓄)的关系是一个持久争论的经典问题。本文基于中国社会不同地区之间的复杂性与多样性,通过多层次线性回归模型的构建,探索基本养老保险在参保类型和保障水平方面对居民消费影响的地区性差异。研究结果表明:城、... 养老保险与居民消费(储蓄)的关系是一个持久争论的经典问题。本文基于中国社会不同地区之间的复杂性与多样性,通过多层次线性回归模型的构建,探索基本养老保险在参保类型和保障水平方面对居民消费影响的地区性差异。研究结果表明:城、乡基本养老保险的参保者比其他类型养老保险参保者或未参保居民的消费支出更多,且在社区、村庄层面存在显著差异;另外,在人均初始生活水平较低、经济欠发达的地区,公共养老金单位增长所带来的家户边际消费倾向要高于初始人均生活水平较高、经济较为发达的地区。可见,基本养老保险与居民消费的关系需要分人群、分地区看待。 展开更多
关键词 基本养老保险 参保类型 保障水平 居民消费 多层次线性回归
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