基于CASA模型的内蒙古地区草地生产力估测

Estimation of Grassland Productivity in Inner Mongolia Based on CASA Model

草地生产力水平估测是草地生态健康诊断和地区草地可持续发展规划制定的基础工作之一。有鉴于此,此次研究利用CASA模型,综合考虑气温和水分对植被生长的影响,对内蒙古地区草地初级净生产力进行估算。该模型估算结果和使用MOD17A3H数据计算的结果相关系数可达0.935,说明模型估测结果具有较高的准确性。使用该模型估测内蒙古草地生产力可知,草地NPP呈现出自西向东、由南向北递增的趋势。使用Hurst指数法分析可知,SNPP由增加变为减小占比最高的类型为低地盐化草甸类,其次为温性草甸草原类,分别为19.43%和17.59%。

The estimation of grassland productivity level is one of the basic work of grassland ecological health diagnosis and regional grassland sustainable development planning.This study used Carnegie-Ames-Stanford Approach model(CASA)to estimate net primary productivity(NPP)of grassland in Inner Mongolia,considering the effects of temperature and water on vegetation growth.The correlation coefficient between the estimated results of the model and the results calculated with MOD17A3H data reached 0.935,which indicated that the estimated results of the model had high accuracy.Using this model to estimate grassland productivity in Inner Mongolia showed that grassland NPP increased from west to east and from south to north.The Hurst index analysis showed that the highest proportion of SNPP from increasing to decreasing was lowland saline meadow,followed by temperate meadow steppe,with 19.43%and 17.59%respectively.