基于GIS技术的青海省草地类型分类研究

GIS-based classification of grassland types in Qinghai

分析青海省50个气象台站1971-2006年的>0℃年积温平均值和年降水量平均值,以及各站的海拔高度和纬度值,建立年积温和年降水量的估算方程。在GIS环境下,根据年积温和年降水的估算方程,以及青海省高程资料,插值出分辨率为4 km×4 km的各个格点的年积温和年降水量值,然后根据湿润度公式计算出每个格点的湿润度值,最后根据综合顺序分类法第一级——类的检索图,确定各个格点的草地类型。研究结果表明,青海省天然草地共有18类,其中寒冷潮湿多雨冻原、高山草甸类的面积最大,约占草地总面积的50%。

The data of 〉 0 ℃ annual accumulation temperature （AAT）, the annual precipitation （AP）, altitude and latitude of 50 meteorological stations from 1971 to 2006 in Qinghai were analyzed and the model for estimating AAT and AP was established. Based on the model and altitude data, the AAT and AP values were obtained by interpolating under the GIS environment, and the resolution was 4 km × 4 km. The moisture index of each grid was calculated. And then, the grassland type of every grid was determined by the Integrated Orderly Classification System of Grassland （IOCSG）. The results showed that there were 18 classes. In which, the area of frigid perhumid rain tundra and alpine meadow was the most and accounted almost half of the total area of grassland in Qinghai.