伊犁地区植被生产力的时空分异及其与地形因子关系研究

基于MODIS·NDVI数据、气象数据和土地利用等数据采用CASA模型定量反演得到2012年—2014年伊犁地区以月为周期，空间分辨率为500 m的植被NPP.分析了研究区植被NPP的时空分布特征，探讨了不同植被类型对NPP的贡献率以及地形因子对NPP的影响.研究结果表明：2012年—2014年伊犁地区植被NPP的年平均值为200 gC·m－2·a－1，空间上呈现出东部大于西部的特征；不同植被类型的月均NPP呈现3～7月增加，7～11月下降的趋势.但不同植被类型月均NPP的变化速率和变换幅度存在较大差异；草地对研究区NPP总量贡献率最大为58.59%，其次是农作物，贡献率为31.45%；针叶林和阔叶林对研究区的贡献率基本相同，分别为3.75%、3.60%；稀疏植被贡献率最小仅为2.61%；研究区年均NPP随海拔和坡度的增加均呈现出先增加后减小的特征；通过验证表明，利用CASA模型对伊犁地区植被NPP估算的结果与MOD17A3产品一致性较好.

Study on the spatial-temporal differentiation of vegetation productivity in Yili Area and its relationship with terrain factors

Based on MODIS · NDVI data， meteorological data， and land use data， this paper uses the CASA model to quantitatively invert the vegetation NPP in Yili from 2012 to 2014 with a monthly cycle and a spatial resolution of 500 m. The temporal and spatial distribution of vegetation NPP in the study area was analyzed， and the contribution rate of different vegetation types to NPP and the influence of topographic factors on NPP were discussed. The results show that the annual average value of vegetation NPP in Yili region from 2012 to 2014 is 200 gC·m－2·a－1， which shows the characteristics of the eastern part being greater than the western part in space. The NPP of different vegetation types increased from March to July and decreased from July to November. However， the monthly average NPP change rate and transformation range of different vegetation types are quite different. The maximum contribution rate of grassland to the total NPP in the study area is 58.59%， followed by crops， which contribute 31.45%. Thecontribution rate of coniferous and broad-leaved forests is basically the same， which are 3.75% and 3.60%， respectively； the minimum contribution rate of sparse vegetation is only 2.61%； the annual average NPP of the study area increaed first and then decreased with the increase of altitude and slope. The results of using the CASA model to estimate the vegetation NPP in Yili area are in good agreement with the MOD17A3 product.