中文摘要：

在土地利用分类的基础上，剔除山地、丘陵、岗地、水域及建筑用地等类型，研究辽西北地区风蚀荒漠化问题，试图找到一条半湿润易旱的界线。研究以TM、MODIS影像为数据源，以多种植被指数为参考指标，运用决策树方法对研究区进行分类，结果显示：非荒漠化、轻度、中度、重度与极重度风蚀荒漠化面积分别占辽西北总面积的44．38％、25．15％、18．97％、9．34％和2．16％。同时，采用经验式k=0．16∑≥10℃／r计算干燥度，对计算结果进行Kriging插值，对比1．1、1．15、1．2、1．25和1．3五条干燥度等值线，发现：（1）选择干燥度1．2线为分界线能满足半湿润易旱区荒漠化易发生程度判别的要求，该线的北部属半湿润易旱区；（2）1．2线作为南北两部分非荒漠化、重度极重度荒漠化和耕地的分界线，效果较其他四线显著；（3）实地调查工作表明1．2线可作为辽西北地区壤土与砂土的界线，具重要的实践意义。由此可见，基于荒漠化分级结果选择干燥度1．2线科学上较为合理，实践上有利用价值。

英文摘要：

Based on land use map, this paper excluded mountains, hills, water, and constructions, and studied wind erosion desertification in the northwestern part of Liaoning Province, with the purpose of finding a semi-humid drought-prone line. This paper took TM and MODIS images as data source and some vegetation indexes as index by using decision tree to classify the study area. The results showed that non-desertification, light, moderate, severe and extremely severe wind erosion desertification area accounted for 44.38%, 25. 15%, 18.97%, 9.34% and 2.16%, respectively. Meanwhile, this study used empirical formula k=0.16∑≥10℃/r to calculate aridity, and then interpolated aridity values by using Kriging method. Comparing aridity line 1.1, 1.15, 1.2, 1.25 and 1.3, we found. （1） Selecting line 1.2 meets the requirement of judging the extent of desertification in semi-humid areas. （2） Line 1.2 is better than other lines on distinguishing nondesertification, severe and extremely severe desertification, and arable land. （3） Field investigations showed that line 1.2 could be the boundary of loam and sand in the northwestern part of Liaoning Province, and have important practical significance. Thus, on the basis of classification results, selecting line 1.2 is reasonable in science and valuable in practice.