土地利用和气候变化对区域净初级生产力的影响

应用以遥感观测数据驱动的GLO-PEM模式模拟估计的中国北方20年的NPP数据同其20年气候数据结合,同时利用通过遥感宏观调查所得的两期土地利用数据,分析20年气候和土地利用变化对区域净初级生产力(Net Primary Productivity,NPP) 的影响的时空特征。分析结果表明,20年来研究区域年均温度显著增加(年均增温0.064 oC),年降水量明显减少(年降水减少率为1.49 mm/年),NPP以减少趋势为主(年减少率6.9 TgC)。研究区域NPP的变化受旬(月) 均温和旬(月) 降水量和季节温度和季节降水的变化影响显著。季节NPP同季节降水和温度的相关性在空间上同植被覆盖表现出高度的一致性,其相关系数大小随着不同植被覆盖类型变化而变化。通过分析可见,就整个研究区来说,发生土地利用变化的区域仅占整个研究区域的5.45%, 气候对整个研究区域NPP的影响占主导地位(占了总影响量的90%);土地利用发生区域土地利用的作用占了绝对地位,土地利用的影响占了约97%。整个研究区域近20年来因为降水明显减少,温度显著升高,导致NPP明显下降,在两期土地利用间隔时间段内(约10年) 因气候影响NPP减少了78 (±0.6) TgC。因为土地利用的变化导致NPP减少9 (±0.2) TgC。气候和土地利用共同作用是研究区域的NPP减少87 (±0.8) TgC。

Impacts of Land Use and Climate Change on Regional Net Primary Productivity

Combined with recent historical period of climate data and two periods of land use data sets from remote sensing data, we test the net primary productivity (NPP) data sets over last 20 years in North China modelled by the satellite data-driven Global Production Efficiency Model (GLO-PEM) for detecting the widespread spatial and temporal characteristics of the impacts of climate and land use change on the regional NPP. Our results shows that over the past 20 years, the average annual temperature in the research region has remarkably increased by more than 0.064^oC, but over the same period, there has been a 1.49 mm decrease in annual precipitation and decrease in NPP by an annual rate of 6.9 TgC. The NPP changes in the study region were greatly affected by the average temperature and precipitation by ten-day periods as well as the seasonal temperature and precipitation. The correlation between seasonal NPP and seasonal precipitation and temperature is highly consistent with land cover spatially, and the correlation coefficient changes with the changes of vegetation types. The analysis reveals that the areas of change in land use only take up 5.45% of the whole study region, so the impacts of climate changes on the NPP dominate (90% of the total). However, land use plays an absolute dominative role in the areas with land cover changes, accounting for 97% of the total. Over the past 20 years, the NPP in the whole study region remarkably reduced due to obvious precipitation decrease and temperature rise. Between two periods of land use (about 10 years), the changes in climate are predicted to cause a decrease in NPP by 78 (±0.6) TgC, and combined impacts of climate changes and land use to cause a decrease in NPP by 87 (±0.8) TgC.