中文摘要：

利用卫星遥感数据和气象资料,分3个高程层面模拟了青藏高原地表太阳辐射（SOL）,并以此驱动CASA模型估算1983-2012年青藏高原植被的净初级生产力（NPP）,分析NPP的时空演变模式,而后探讨了NPP对气候因子的响应关系.研究结果表明：（1）分不同高程层面建立的太阳辐射模型能够更合理地反映青藏高原地表太阳辐射的空间分布特征,模拟精度高于其他相关模型.（2）青藏高原植被NPP的空间分布表现为自东南向西北逐渐递减的趋势.高原西北部降水量小于400 mm的区域内植被NPP的主导因子是降水,东南部降水量大于400 mm的区域内植被NPP的主导因子是温度.（3）青藏高原植被NPP的演变趋势存在显著空间分异.总体上高原西北部植被NPP近30年变化相对稳定,其中1983-1992年,NPP增加区域主要分布于高原中部,在高原东南部则呈现减少趋势;1993-2002年,高原大部分地区NPP呈增加趋势,NPP减少区域集中在高原东部地区;2003-2012年,高原东部、南部NPP增加趋势明显,高原东南部NPP呈减少趋势.（4）总体上,1983-2012年青藏高原NPP总量波动范围为0.494～0.590 Pgc/年,变化率为0.0187 Pgc/10年,呈现“缓慢增加-缓慢减少-快速增加”的趋势,其中年均温度增加对NPP的变异有显著影响（R2=0.456,P＜0.001）.

英文摘要：

Based on satellite remote sensing data and meteorological data, this research simulated surface solar radiation over the Tibetan Plateau in three elevation levels, with which the CASA model was drived to estimate vegetation net primary productivity （NPP） on Tibetan Plateau from 1983 to 2012. Then the spatial-temporal variation patterns of NPP and its responses to climate factors were studied based on pixel spatial scale. The results showed：（1） The solar radiation model this research established in three elevation levels could reflect spatial distribution characteristics of surface solar radiation over the Tibetan Plateau more reasonably. This research had a higher precision in solar radiation than other related model. （2） The spatial changes of NPP on the Tibetan Plateau were remarkable and they decreased from southeast toward northwest, correspond with the hydrothermal conditions and vegetation types. Vegetation productivity was conditioned by different meteorological factors in the southeastern and northwestern plateau. The dominant factor of vegetation NPP was temperature in southeast （precipitation more than 400 mm）, and NPP increased dramatically with the rise of temperature, while the dominant factor was precipitation in northwest （precipitation less than 400 mm）. Precipitationshowed weak inhibitory effect on productivity increase in areas where precipitation was more than 900 ram. Probably because precipitation increased soil erosion to some extent, and soil erosion decreased the soil organic matter content, therefore, reduced productivity. （3） Interannual variability of NPP on Tibetan Plateau had a significant spatial difference. Vegetation NPP remained relatively stable in northwest plateau for many years. From 1983 to 1992, areas where NPP increased concentrated in the central plateau, while areas where NPP decreased concentrated in the southeast plateau. From 1993 to 2002, most areas of the plateau showed an increase trend in NPP, while areas where NPP decreased concentrated i