基于黄河源区1959-2008年月平均气温、最高气温、最低气温、相对湿度、降水量、风速和日照百分率等气候要素资料,应用修订的Thomthwaite Memorial模型计算了50 a植被净初级生产力(NPP),分析其年际和年代际变化特征及其对气候变化的响应.结果表明:1959-2008年间,研究区年NPP变化呈显著上升趋势,NPP变化曲线线性拟合倾向率在95.502~190.72 kg/(hm2·10a)之间,20世纪90年代后NPP较高.20世纪70年代表现为“冷干型”气候特征,NPP距平百分率偏少1.1%~2.1%;2001-2008年均为“暖湿型”气候特征,NPP距平百分率偏多2.1%~4.5%.影响黄河源区NPP变化的主要气候因子是降水量、最大蒸散量和平均最低气温.“暖湿型”气候对植被净生产力增加最有利,黄河源区NPP可增加5.5%~8.5%.而“冷干型”气候造成植被净生产力下降5%~9%.若2050年在“暖湿型”气候情景下,黄河源区未来NPP较多年平均值增加7%~17%.
Based on observational climatic data of monthly average temperature, maximum temperature, minimum temperature, relative humidity, precipitation, wind speed and sunshine duration in the source region of Yellow River in 1959--2008, the net primary productivity (NPP) for 50 years was computed with the application of revised Thornthwaite Memorial Model. In addition, the inter-annual change and the seasonal difference of NPP were analyzed, and the responses of net primary productivity to climatic changes was discussed as well. The main results were as follows: In 1959--2008, the annual NPP in this region had an increasing trend, with a linear fitting rate of annual NPP change curves being 95.502 ~ 190.72 kg/(hm2" 10a), the NPP appeared a high rate mostly after 1990s. The cold and dry cli- mate occurred in the 1970s, the NPP of which was 1.1% - 2.1% less than the annual average NPP; and the warm and wet climate appeared in 2001--2008, the NPP of which was 1.1% - 2.1% more than the annual average NPP. The main factors which influenced the NPP were precipitation, maximum evapotranspiration and average minimum tempera- ture. The warm and wet climate benefited the growth of the NPP with an average increment of yield by 5.5 % ~ 8.5 % in the source region of the Yellow River, while the cold and dry climate had an adverse impact on NPP with an average reduction of yield by 5 % - 9 %. If the future climate in the region would become warm and moist, the NPP could increase by 7% - 17% in 2050.