内蒙古草地NPP变化及其对气候的响应

Variation of net primary productivity of Grassland and its response to climate in Inner Mongolia

植被净初级生产力(Net Primary Productivity,NPP)是衡量植物群落在自然环境条件下生产能力的重要指标,NPP的变化直接反映了生态系统对环境气候条件的响应,因此可以作为生态系统功能对气候变化响应的研究指标。本文利用卫星遥感资料和地面气象观测资料,利用光能利用率模型估算了内蒙古地区1982-2003年4-10月草地NPP,并计算了与NPP密切相关的几个气候因子,分析了1982-2003年内蒙古地区草地NPP年际性变化规律、气候因子的年际变化规律,以及草地NPP对主要气候因子的响应关系。结果表明:1982-2003年内蒙古草地生长季的NPP呈波动中增加趋势,NPP的年平均递增率为C0.0036g·m-2·Gr-1;草地NPP的空间分布与生物温度(BT)及可能蒸散率(PER)呈显著负相关,与降雨量(RAIN)、湿润度(K)及实际蒸散(AE)呈极显著正相关。内蒙古地区,草地NPP受降雨量(RAIN)及生物温度(BT)的影响较大,但NPP的变化受RAIN的影响更为明显;内蒙古地区不同草地类型的NPP变化对气候因子的响应略有不同。

Net Primary Productivity is a key indicator to evaluate the productivity of vegetation community in natural environment. The variation of NPP, which directly reflects the ecosystem response to climate, could be an indicator of the ecosystem response to climate changes. Using remote sensing data and ground meteorological station data, we estimated NPP of grassland during the grow- ing season from 1982 to 2003 in Inner Mongolia using the light use efficiency model proposed by Montieth in 1972, and calculated several climatic factors which are closely related to NPP. We analyzed the annual NPP variations of grassland in Inner Mongolia from1982 to 2003, as the climate factors, and analyzed the relations between the NPP and climate factors. The results showed that the NPP of grassland was increased fluctuations during growing season in Inner Mongolia from 1982 to 2003, and the average increase rate is 0.003 6 g C·m^-2·Gr^-1. The spatial correlation between NPP, Biological Temperature （BT） and Potential Evapotranspiration Rate （PER） is significant negatively ,and significant positive with rainfall （RAIN）, moisture humid （K） and Actual Evapotranspiration （AE）.In Inner Mongolia, The NPP of grassland was most impacted by RAIN and BT, more obviously by RAIN. Different type grassland＇s NPP responded slightly different to climate changes in Inner Mongolia.