贵州典型喀斯特流域土地利用空间格局及水文干旱研究

干旱是全球性普遍发生的一种自然现象,而喀斯特干旱不能简单归因于"气候异常、降水量减少"。在贵州省选择40个典型流域为研究样区,利用面向对象分类技术,构建土壤水体指数(SWBI),提取土地利用类型的遥感信息;借用景观指数计算软件(Fragstats4.0),计算土地利用类型的景观密度指数(PD)、最大斑块指数(LPI)、形状指数(SI)、景观分维指数(FDI),分析土地利用类型的空间分布格局;探讨不同土地利用格局下的流域储水空间的变化、流域地表储水能力的大小,研究土地利用类型及其空间分布变化对水文干旱的影响。研究表明:①疏林、旱地和灌木林分布相对集中、空间分布变化较大,水体和城镇分布相对分散、空间分布变化较小;②土地利用类型的斑块密度分布及最大斑块分布对水文干旱影响较大,土地利用类型的斑块边界分布及斑块形状分布对水文干旱影响较小;③土地利用类型的斑块密度指数、最大斑块指数、斑块形状指数及斑块分维指数越大,则土地利用类型对水文干旱影响越小。

Study on Spatial Pattern of Land-using Types and Hydrologic Droughts for Typical Karst Basin of Guizhou Province

Drought is a natural phenomenon of the global widespread occurrence, while Karst drought can not simply be attributed to the climate anomalies, reduced-rainfall. In this paper, 40 typical watersheds in Guizhou Province were selected as the sample areas, the soil water body index (SWBI) was built by using object-oriented classification techniques, to extract the remote sensing information of land-using types. To calculate the landscape density index (PD), largest patch index (LPI), shape index (SI), and landscape fractal dimension index (FDI) of the land -using types by using the calculation software of landscape indices (Fragstats4.0), and analyze the spatial distribution pattern of land-using types. To explore the variation of watershed storage-space under the different land-using patterns, the sizes of watershed water-storing capacity, and study the affect of land-using types and its spatial change on hydrologic droughts. The study has shown that: (1) The distributions of woodland, dry and shrubbery are relatively concentrated, the larger the spatial variation, and that of water and urban is relatively dispersed, the smaller the spatial variation; (2) The affects of the plaque density and largest patch distributions of land-using types on hydrologic droughts are larger, and the smaller the patch edge and patch shape distributions of land-using types; (3) The larger the patch density index, largest patch index, patch shape index and plaque fractal dimension index of land-using types, the smaller the affects of land-using types on hydrologic droughts.