基于PCA方法的长江口滩涂围垦区土地利用动态综合评价及驱动力

DYNAMIC CHARACTERISTICS AND DRIVING FORCE ANALYSIS OF LAND USE IN DIFFERENT RECLAMATION TIME BASED ON THE PCA COMPREHENSIVE EVALUATION MODEL AT THE YANGTZE ESTUARY

基于1987、1995、2000和2006年长江口TM、ETM遥感影像,采用"空间代时间"和主成分分析(PCA)综合评价模型的方法,对长江口奉贤不同围垦年限土地利用动态特征进行了综合评价分析。利用南汇围垦区土地利用动态变化对综合评价的结果进行验证。表明:(1)围垦区土地利用程度指数随着围垦年限增加而呈线性升高趋势(R2=0.4577),GM(土地利用多样性指数)呈现指数上升趋势并在围垦后35～40a达到稳定态;(2)PCA土地利用综合评价指数(F)与农耕用地正相关(水田>大棚用地>旱地>林地>园地),与反映滨海特征类型(养殖塘>草地>开放水域>光滩)呈负相关;(3)土地利用PCA综合评价指数(F)随围垦年限增加呈现对数增长(R2=0.5119)并在围垦后40a左右达到稳定态,回归分析表明F值能很好反映土地利用程度指数(L)和多样性指数(GM)的变化趋势;(4)不同围垦年限土地利用动态变异驱动力:人为因素>自然因素。

Based on TM（30m） data in 1987,1995,2000 and 2006,the characteristics and comprehensive evaluation of land use dynamics of different reclamation time on the northern Hangzhou Bay were analyzed with the method of spatial sere substituting for time sere and Principal Component Analysis（PCA）.A comprehensive evaluation model of land use dynamics in the study has been established and verified with land use change data of Nanhui reclamation zones.Conclusions showed：（1） Land use level comprehensive index（L） tended to linearly increase（R2=0.457 7）with the increase of reclamation time.Land use diversity（GM） also tended to increase,and reached a steady state between 35 and 40 years.（2） Change of agricultural land positively correlated with the comprehensive evaluation index（paddy fieldgreenhousefarm landforestorchard）,while nature dominated land types（breeding pondgrass landopen watermud flat） negatively correlated with the F-value.（3） F-value tended to increase（R2=0.511 9） with the increase of reclamation time,and reached a steady state after about 40 years of reclamation.Regression analysis showed that F-value reflected the information of land use degree index（L） and diversity index（GM） well.（4） Land use dynamic was impacted by following driving force factors：anthropological factorsnatural factors.