干旱区绿洲LUCC马尔柯夫过程分析——以新疆于田绿洲为例

土地利用/覆盖变化(LUCC)在干旱区环境变化及生态监测中具有重要意义。本文选取塔里木盆地南缘典型绿洲于田县,利用TM遥感影像,基于Markov模型预测了于田绿洲未来的发展趋势,得出绿洲将向良性方向发展的结论。通过对Markov模型中不同步长收敛结果的讨论,可以看出间隔10 a1、2 a步长的马尔柯夫过程与间隔两年的马尔柯夫过程有着明显的不同,短时间序列(两年)具有很大的随机特性,说明马尔柯夫模型中时间尺度是一个重要环节。由本文研究可以看出,基于遥感的Markov模型可以分析绿洲的变化趋势,在干旱区绿洲LUCC及其环境动态监测中具有重要的实用意义。

Analysis of Markov process of LUCC in oasis of arid area——A case of the Yutian Oasis

With the current problem of population,resources and environment becoming increasingly intense day by day,the land use /land cover change(LUCC) is one of the core topics on the Present World Change Study.And with the worsening of the global environment,the exhausting of energy and the population explosion,the controversy between the development of oasis economy and the environment has become more and more sharp,which has formed a serious threat to the sustainable development the oasis economy.As a result,the reasonable,coordinate and continuous development is the experimental topic with great theoretical and practical significance in the world.Land use/cover(LUCC) change has vital significance in environmental variation and the ecology monitoring in the arid and semi arid areas.This article selects the typical oasis of Yu Tian in the south of the Tarim basin,uses the TM remote sensing images in the year of 1989,1991,1999 and 2001.First we take the farmland,the high,middle and low density grassland, the desert,the water body,and the salty land as a classification system.Based on the detailed analysis and pretreatment to the remote sensing imagery,we obtained relatively high precision classification result.Through the dynamic change examination,this paper established many kinds of Markov chain model under the different steps.That is,the much time-gap Markov chain model,also the precision of each model has been evaluated.After this work,we finally predicted the future LUCC by Markov chain model and validated it.By detailed analysis we finally draws the conclusion from these models:The arid area LUCC process is conforms to Markov process.In establishing the Markov model process,the length of stride choice is extremely important,because under the different length of stride model,possibly can appear the completely different result.Through discussing restrain results of the different length of stride in the Markov model,it can be seen that the Markov process is obviously different between every 10 years,or 12 years lengths of stride and every two years and shows that the time criterion is an important link in the Markov model.By analyzing and discussing the LUCC process above,unifying future land use result by Markov process,the paper finally drew the following conclusion to future better development of this research area.Whether the influence of future LUCC to the environment is good or not,is decided in the very great degree by the way of the land development and using of the humanity,and as well as the local maintaining level to the oasis-desert belt.Obviously,the influence of the humanity activity to LUCC in the future is increasing gradually.Also,if the humanity strengthens the consciousness of environmental protection of the oasis in the arid area,and increases the protection dynamics,and positively protects and rebuilds ecology frail belt,the future of oasis definitely may develop towards the benign direction.In other words,the outside of ectone expands to desert,and desert area reduces;At the same time,lawn cover density of ectone increases gradually,and the vegetation cover region increases;and the oasis can expand in the edge of ectone.According to the study in this article we may see that we can analyze the change tendency of the oasis based on the remote sensing using Markov model,which has the vital practical significance in arid area oasis LUCC and environment dynamic monitoring.