中国县域人均粮食占有量空间变异特征研究

运用空间变异函数和空间自相关分析模型,分析1990年以来中国县域人均粮食占有量的空间分布格局、空间变异特性和分维特征。结果表明:在总体空间格局上,中国县域人均粮食占有量表现出较强的空间自组织性,热点区域在东北平原区积聚,东南沿海出现了新的冷点带,总体差异扩大;县域人均粮食占有量空间连续性和自组织性增强,空间分异格局中的随机成份在降低,而由空间自相关引起的结构化分异日益显著;从不同方向的空间变异格局看,东南—西北方向人均粮食占有量的空间差异较小,而南—北方向人均粮食占有量的空间差异最大。

Spatial variability of per capita grain possession at county level in China

As an important part of food security structure,spatial structure is the distribution pattern and combining form of grain production in the space.This article,taking China as an example,described the spatial changes of per capita grain at county level since the 1990 through the related analysis of ESDA as well as other tools such as Moran’s I,Getis-Ord General G,Getis-Ord Gi and the function of variogram and its amount of fractal dimension as scale index.Based on four time discontinuity surfaces,some conclusions are drawn as follows:1) Considering the overall spatial per capita grain framework,per capita grain possession at county level in China shows a significantly trend of positive spatial correlation and similar areas cluster in space.The space structure of the hotspot distribution tends to be the circular space structure centered on Northeast Plain,while the coldspot distribution tends to be the circular space structure centered on Qinghai-Tibetan Plateau and to be ribbon structure clustered in Southeast Coastal Area.The overall difference is enlarging.2) Considering the overall spatial variability,per capital grain growth in China shows a strong trend of spatial autocorrelation.Randomness in the differentiation of per capital grain growth space patter reduces.3) According to the space-time mechanism,the spatial framework of per capita grain tends to be more continuous and self-organized.That means the spatial continuity and structural distribution of per capita grain,as well as the mechanism of structural difference caused by spatial autocorrelation become more and more obvious and remarkable.The homogeneousness of per capital grain in the direction of southeast-northwest is typical for its relatively small spatial variability.Effective regulation and favorable policies can promote per capita grain possession and guarantee regional grain safety.