基于改进CASA模型估算得到的草地NPP,分析了2000～2009年松嫩平原西部草地NPP时空分布特征及变化趋势.结果表明:2000～2009年松嫩平原西部草地NPP总量在8.46～11.22Tg C之间,平均值为9.92Tg C,呈波动上升趋势；受气温、降水及太阳辐射季节变化的影响,NPP存在明显的季节变化,积累期主要集中在水热条件搭配较好的4～10月,占年度NPP总量的99.60％;2000～2009年,春、夏、秋、冬四季草地NPP平均值分别为6.82gC· m-2·a-1、79.68gC· m-2·a-1、13.57gC·m-2·a-1、0.09gC·m-2·a-1,即夏季＞秋季＞春季＞冬季.空间上,松嫩平原西部草地NPP由南向北呈明显增加趋势,最低值分布在吉林省境内的中部地区；2000～2009年,黑龙江省各年草地NPP均高于吉林省,说明在松嫩平原西部黑龙江省草地长势优于吉林省；基于像元的NPP年际变化趋势分析表明,占研究区总面积3/4的草地NPP表现为增加趋势,NPP显著增加的草地面积是显著降低面积的7.6倍,说明2000～2009年间松嫩平原西部草地长势呈明显好转趋势.%Based on the grassland net primary productivity(NPP) simulated by improved CASA model, spatial and temporal patterns of grassland NPP were analyzed from 2000 to 2009 in western Songnen Plain. Total grassland NPP was between 8. 46 and 11. 22 Tg C, with average of 9. 92 Tg C, showed an increasing trend. Affected by the seasonal change of temperature, precipitation and solar radiation, obvious seasonal changes in NPP appeared, and accumulating period focused on April to October, accounted for 99. 60% of total NPP. NPP in spring, summer, autumn and winter was 6. 82gC · m-2 · a-1, 79. 68gC · m-2 · a-1, 13. 57gC · m-2 · a-1 , 0. 09gC · m-2 · a-1 respectively, I. E. Summer>autumn>spring>winter. Spatially, grassland NPP increased clearly from the south to the north, and minimum located in the middle of Ji-lin Province that belonged to western Songnen Plain. From 2000 to 2009, Grassland NPP of Heilongjiang Province was higher than that of Jilin Province, which implied that grass grew better in Heilongjiang Province. Changing trend analysis illustrated that grassland NPP accounting for 75% of the total researched area showed an increasing trend, the area with marked increased NPP was 7. 6 times bigger than that of marked decreased NPP. Overall, grassland in western Songnen Plain was improved distinctly in the 2000~2009.
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