乡镇尺度金塔绿洲时空格局变化

Spatio-temporal change on township scale of Jinta oasis in the latest 20 years

基于遥感、GIS技术和1990、1999、2006和2009年4期Landsat TM/ETM+遥感影像等,利用绿洲变化幅度、动态度模型、绿洲变化趋势指数模型及绿洲化荒漠化转移矩阵,开展乡镇尺度上金塔绿洲时空变化及分异研究。结果表明:1990—2009年间,金塔绿洲不断扩张,荒漠面积呈现减少趋势,绿洲净增长面积达199.49 km2。金塔绿洲整体处于非平衡状态,不同乡镇绿洲变化程度不同,乡镇绿洲规模变化强弱顺序为羊井子湾乡>场站机关辖区>东坝镇>三合乡>古城乡>金塔镇>中东镇>大庄子乡>西坝乡。金塔绿洲聚集度增加,景观破碎化程度减少,荒漠基质优势度降低。绿洲扩张区主要有羊井子湾乡、场站机关管辖区、东坝镇、金塔镇、古城乡和三合乡等。近20年来,金塔绿洲变化主要受人文与社会因素的影响,水资源的开发利用是绿洲扩张的前提条件,人口(含移民迁入)、经济发展、政策和科技进步是主要的驱动因素。

Based on Landsat TM/ETM＋ images in 1990,1999,2006 and 2009 of Jinta and RS and GIS technique,oasis change models（change trend,dynamic model,change trend indexes,oasis-desert transition matrix） were used to analyze the spatio-temporal change of Jinta oasis in the latest 20 years.The results showed that：（1） the area of oasis increased continuously and desert decreased correspondingly,and the oasis area increased by 199.49 km2 from 1990 to 2009.（2） Jinta oasis was in an unbalanced status,and the area extent degrees of different oasis were different in the latest 20 years.The extent of oasis area of different township were ranked as Yangjingziwan town＆gt;Precinct of Jinta county＆gt;Dongba town＆gt; Sanhe town＆gt; Gucheng town＆gt; Jinta town＆gt; Zhongdong town ＆gt;Dazhuangzi town ＆gt;Xiba town.（3） The whole landscape fragmentation of Jinta oasis was decreased,the contagion was increased,and the matrix component was reduced.The oasis which expanded apparently were mainly located in Yangjingziwan town,Precinct of Jinta county,Dongba town,Jinta town,Gucheng town,and Sanhe town.（4） The human-dimensional factors were the major cause of the spatio-temporal change of Jinta oasis in the latest 20 years.Water resources development and utilization was the prerequisite of oasis expansion,and oasis change were co-effected by human activities,immigrate,economic development and regional policy and scientific and technological advance.