基于CA-Markov的河西走廊土地利用变化研究

基于河西走廊1990年、2000年土地利用矢量数据，通过空间叠加和构建土地利用分布与变化的1 km-Grid数据集以研究20世纪90年代土地利用分布与变化的数量特征和空间格局特征，并运用马尔可夫模型和元胞自动机技术对2010年土地利用分布情景进行预测。研究表明：河西走廊以未利用土地和草地为主；20世纪90年代，耕地、城乡工矿居民用地增加，而林地、草地、水域和未利用土地减少；多种土地利用类型的开垦在区域土地利用变化中处于主导地位，其中“草地→耕地”和“未利用→耕地”2个变化类型的规模最显著。主要交通线与大的河流附近人类活动强烈，因而土地利用类型及变化类型比较多样，空间格局复杂。CA-Markov模型模拟结果表明2000～2010年间6个土地利用类型将保持原有的变化趋势和变化速率，因此，迫切需要加强对林地、草地和水域的保护，控制和阻止盲目开垦耕地的行为，推进退耕还林还草工程，促进区域生态环境质量的保护和改善。

Land use change in Hexi corridor based on CA-Markov methods

Based on land use data of Hexi corridor in 1990 and 2000, which were interpreted by the Landsat TM remote sensing images, the 1 km-grid data sets of land use distribution and land use change were established in order to study the spatial pattern characters of land use change in 1990s. And, by using the Markov process theory and the cellular automata(CA) method, the scenarios of land use in 2010 was simulated. It was proved that, the unused land and grassland were the dominant land use types in Hexi corridor, and the other types distributed very sparsely. The farmland and the built-up area have increased quickly and remarkably in 1990s with the extensive reclamation and exploitation of grassland, woodland, water-body and unused land. Among the various transformation types, changes from grassland and unused land to farmland spread most widely. Regions along railways and main roads as well as big rivers had high local variability of land use distribution, and therefore they became the hotspot area of land use change in 1990s. The simulation result by the CA-Markov method has indicated that, from 2000 to 2010, trends of land use evolution as well as its rate will keep constant. Therefore, it is urgent to protect the grassland, woodland and water-body from irrational reclamation.