岷江上游干旱河谷边界波动的定量判定及其演化特征

Quantitative Determination of Boundary Fluctuation in Arid Valley of the Upper Min River and Its Evolution Feature

在山区人口迅速增加和社会经济高速发展的进程中,干旱河谷作为山区生态系统的重要组成部分之一,承载了严重的被干扰和过度利用。在RS与GIS技术的支持下,本研究选择岷江上游干旱河谷作为研究对象,应用马尔科夫预测法和土地利用动态变化空间分析测算模型,开展干旱河谷边界波动的定量判定及其演化特征研究。研究结果表明:岷江上游干旱河谷区面积与上边界在逐年增加,上边界平均每年沿垂直方向抬升约5 m,在未来较长时间内,干旱河谷面积的增长趋势将会越来越强;其中,1970至2010年干旱河谷转化速率(TRL_(70-2010))呈现不断上升趋势,分别为TRL_(70)=1.44%,TRL_(80)=0.95%,TRL_(90)=2.32%,TRL_(2000)=2.45%,TRL_(2010)=3.59%;1990至2000年期间干旱河谷新增速率(IRL_(90-2000))最大,属于高速扩展期,在1970至1980年期间新增速率IRL_(70-80)最小;1990至2000年期间干旱河谷"敏感性"最高,其年变化速率(CCL_(90-2000))为13.01%,其次为CCL_(2000-2010)=6.51%,其余时期年均变化速率皆在4%左右。本研究结果可为我国西部灾害多发区聚落合理规划、灾害风险管理、人口合理分布与再调整提供重要的科学依据。

With rapid population growth and socio-economic development in mountainous regions of western Chi- na, arid valleys are acting as an important part in support of mountain ecosystems and suffering serious engineered interference and over-exploitation. With the help of RS and GIS technology, this research took arid valleys in the upper reaches of Min River as a case study. It applied the Markov prediction method and the model of dynamic change of land use space analysis calculation to perform a quantitatively investigation on the boundary fluctuation of arid valleys in the upper reaches of Min River and its evolutionary features. Results confirmed that： The area of ar- id valleys in the upper reaches of Min River and its upper border had been growing for years, On an annual average, the upper boundary kept uplifting about 5 m per year in the vertical direction, and the growth trend in the arid valley areas would be getting stronger in the long run; During 1970 to 2010 ,the expansion rate of arid valley（ TRL70_2ol0 ） presented a rising trend,with TRL70 = 1.44%, TRL80 =0.95%, TRL90 =2.32%, TRL2000 =2.45%, TRL2010 = 3.59%. separately; And arid valleys had been highly developing from 1990 to 2000 with a unprecedented maxi- mum rate （IRL90-2000） ,which was regarded as high-speed expansion period,whereas for the period of 1970 to 1980, its rate IRL70-80 dropped to the minimum; As for the period of 1990 to 2000 ,arid valley had the highest＂sen- sitivity＂ ,with a annual rate of change（ CCL90-2000） 13.01% ,followed by CCL2000-2010 =6.51% ,and in the remai- ning period, a average annual rate of change was about 4%. This research achievement can provide important scien- tific basis for rational site planning for settlements, disaster risk management, proper population distribution and re- adjustment in some areas of western China with a high susceptibility in geohazards.