基于CASA模型的甘肃省草地净初级生产力研究

摘要

利用基于遥感数据的光能利用模型-CASA模型估算了2005年甘肃草地生态系统NPP,分析了其空间格局,以及地形因素对草地NPP的影响。（1）实测数据与模拟结果对比表明,修正后的CA-SA模型的可操作性强,仅利用地面气象数据和遥感数据就可以对草地生产力进行模拟,模拟效果较好。（2）2005年甘肃省草地NPP总量为3.76×1013g/（m2.a）,最高值达790.56g/（m2.a）,年均值为139.15g/（m2.a）,由西南向东北逐渐减少。（3）草地NPP季节变化非常明显,夏季NPP达到最大值;冬季植被基本停止生长,草地NPP值最低。4）在海拔3 000～3 500m区域、25°～30°坡度以及东坡草地NPP均达到较高水平。%As a light use efficiency model based on remote sensi the grassland NPP in Gansu Province in 2005. The spatial pattern ng of data,CASA model was set up to estimate grassland NPP and its response to topo graphic factors were also analyzed. Results showed that the improved CASA model indicated better estimation effects and maneuverability with the comparison of estimated and observed data. The total NPP of grassland in Gansu Province was 3.76 × 1 0^13 g/(m2· a),with highest and average value of 790.56 g/(m2· a) and 139.15 g/ (m2·a),respectively. There was obvious seasonal change in the grassland,the NPP was high in summer, and lowest in winter. It represented decreasing trend from northwest to northeast,and higher value in 3 000~3 500 m,25-30°and sunny slope in general.