半干旱地区城市化进程对区域沙漠化的影响

Urbanization progress influence upon regional desertification process in semi-arid zone

在“3S”技术和统计分析的支持下，对库布齐沙漠典型地区1987—2003年间的沙漠化和城市化进程进行了研究。结果显示：达拉特旗的城市化水平呈逐渐增加的趋势，变化在9．1％-19．1％之间，从1998年开始城市化水平进入了相对高增长时期，由之前的平均每年0．53％增加到0．7％。而同期的沙漠化程度呈下降的趋势，由1987年的0．269下降到2003年的0．214。沙漠化程度的变换主要是由半流动和半固定沙丘的变化所导致，其中在1987—1995年期间，半流动和半固定沙丘分别只有2．6％和12．3％保持不变，其余部分主要转移成其他沙丘类型和农田。城市化与沙漠化的相互关系分析表明，在城市化水平较低的1987—1995年（城市化水平变化在9．1％-13．5％之间），城市化与沙漠化之间有显著的线性回归关系[y=-0．0038x＋0．3132（R=0．667〉0．632=α0.05）]；而在城市化水平较高的1995—2003年（大于14％），二者之间的关联程度降低，我国北方半干旱地区的城市化进程对区域沙漠化的影响具有明显的阶段性。

Relationship between urbanization progress and desertification process has been studied by using RS, GIS and GPS techniques and statistic method from 1987 to 2003 in typical area of Kubuqi desert. Results showed that urbanization levels of Dalate Banner gradually increased in this period that varied from 9.1% to 19.1%. There was highest increasing period of the urbanization progress after 1998, the urbanization level of yearly average increase ratio was 0.7% and higher than 0.53% of that before. Meantime, changing trend of desertification degree which was quantitative express of the desertification in whole view was decreased form 0.269 to 0.214 during this period. The changing trend was induced by area fluctuation of semi-mobile and semi-fixed dunes because 2.6% area of semi-mobile dunes and 12.3% area of semi-fixed dunes were unchangeable during 1987 to 1995. And, most changeable area of the semi-mobile and the semi-fixed dunes transferred to other sand-dune types and cropland. A- nalysis of relationship between the urbanization progress and the desertification process indicated that there was significant linear relation in 0.05 level[ y = - 0.0038x ＋ 0.3132 （ R = 0.667 〉 0.632 = α0.05（8） ） ] when the urbanization levels was less than 14%. Conversely, there was not significant relation while the urbanization levels were more than 14%. Therefore, the paper could confirm that urbanization progress impact on the desertification process has period characteristic in semi-arid zone of northern China.