草地蝗虫发生的地形分析是建立草地蝗虫发生预报模型的基础。以青海湖地区为实验区,在Arc/Info和ArcView地理信息系统的支持下,进行草地蝗虫发生与各地形变量(包括海拔高度、坡度与坡向)的叠置分析,提取草地蝗虫发生的地形信息数据库。然后,分别采用T-检验(对连续变量-海拔高度和坡度)和卡方(Chi-square)检验(对类变量-坡向类型)进行各地形变量对草地蝗虫发生的差异显著性检验。结果表明:海拔高度和坡度对草地蝗虫发生的影响极为显著(显著性水平p=0.000),而坡向对草地蝗虫发生的影响不是特别明显(显著性水平p=0.039)。

The topographic analysis of grasshopper outbreak is the base to develop the prediction model for grasshopper outbreak. With the support of Arc/Info and ArcView, grasshopper outbreak information from field sampling is overlapped with elevation, slope and aspect types derived from Digital Elevation Models(DEM) respectively, the databases for each topographic variable of grasshopper outbreak information are obtained and analyzed. Then two-sample t-tests for the continuous variables and chi-square tests for the categorical variables are separately used to test the significance level. The results show that the effects on elevation and slope to grasshopper outbreak are very significant (two significance levels are all 0.000), while aspect’s effect is not very remarkable (significance level is 0.039).