基于马尔科夫模型的吐鲁番市土地覆被动态变化研究

以吐鲁番市1990年TM影像解译数据和2005年、2011年的土地利用图为数据源，通过建立马尔科夫模型来预测该地区土地覆被变化情况。马尔科夫模型的预测精度与模拟步长密切相关，因此，首先以1990年为基础年，基于不同的模拟步长，预测2005年的各地类面积，并与其实际面积相比较，找出最佳模拟步长。其次，用该最佳步长预测2011年以后的土地覆被变化，由此分析该地区土地利用程度和土地利用空间变化动态度。研究表明:（1）未利用地和草地相互转换数量较大；（2）2005年后耕地减少较为迅速，供需矛盾日益突出，基本没有实现耕地占补平衡；（3）在21年间水体减少近6 000 hm²，很可能与全球气候变暖有关；（4）由于建设用地和园地的变化而使得土地利用程度逐年提高，说明经济的发展是土地覆被变化的重要因素；（5）人为因素是土地覆被变化的主要原因，人们正采取越来越有力的手段影响着土地覆被变化。基于上述结论，文章提出了相应建议。

Dynamic Changes of Land Cover Based on Markov Model in Turpan City

The land-cover data obtained from the TM remote sensing images of 1990 as well as land-use map of 2005, 2011 were used in Turpan to set up a Markov model for predicting changes of land-cover. Given the accuracy of prediction in Markov model is closely related to its simulated step, therefore, firstly, 1990 was taken as initial year to predict various areas of land-cover on different classes in 2005, and the optimal simulated step was found out by comparing the minimum difference between the simulate and actual areas of land-cover. Secondly, the changes of land-cover in 2011 was predicted by taking the optimal simulated step in Markov model, then the land use degree and land use space change dynamic were analyzed based on this. Results could be summarized as: (1) the areas of transform between unutilized land and grassland are enormous; (2) the cultivated land decreased quickly since 2005, which indicated that the contradiction between supplement and demand was being increased, and also meant that the balance of the cultivated occupation and supplement had not implemented; (3) nearly 6 000 hectares of water disappeared in 21 years which was largely probably associated with global warming; (4) because the change of construction land and garden plot made the land use degree increase year by year, it exhibited that the development of economy was an important factor resulting in the changes of land cover; (5) anthropic factor was a major reason which led to the changes of land-cover, people were taking more and more powerful means to affect the land cover change. Therefore, some appropriate proposals were also offered according to the above results.