21世纪北半球中高纬度净初级生产力(NPP)变化及其与气候因子之间的关系

基于CMIP5模式模拟的净初级生产力(NPP), 对21世纪初期(2016-2035年), 中期(2046-2065年)和末期(2080-2099年)三种排放情景下(RCP2.6、RCP4.5、RCP8.5)北半球中高纬度陆地NPP的时空变化进行了预估, 并结合气候因子分析了NPP的变化和气温、降水、辐射之间的关系. 结果表明: 相对于1986-2005年, 21世纪北半球中高纬度陆地NPP呈增加趋势, RCP8.5情景下NPP的增加比RCP2.6和RCP4.5情景下更为明显; 在季节变化上, 北半球中高纬度NPP也以增加为主, 且NPP在夏季, 尤其是6月增加最显著. NPP对气候变化的响应存在明显的区域差异性, 在中低排放情景下(RCP2.6、RCP4.5), 相对于1986-2005年, 21世纪北半球中高纬度地区温度显著影响的范围在逐渐缩小, 而辐射和降水显著影响的范围在扩大. 在高排放情景下(RCP8.5), 21世纪北半球中高纬度地区NPP的变化主要与温度有关.

Change of NPP at the mid-high latitude of Northern Hemisphere in the 21st century and its relation with climate factors

Based on the simulated net primarily production (NPP) from CMIP5, the spatial-temporal characteristics of NPP at the mid-high latitude of Northern Hemisphere landmass for three Representative Concentration Pathways (RCP2.6, RCP4.5, RCP8.3) during the early (2016-2035), middle (2046-2065) and late (2080-2099) periods of the 21st century are estimated. Combined with climatic factors, the relation between NPP and temperature, precipitation and surface shortwave radiation is also discussed. The results show that, relative to the reference period of 1986-2005, NPP at the mid-high latitude of Northern Hemisphere will represent an increasing trend during the 21st century, and the increase of NPP under RCP8.5 is greater than that under RCP2.6 and RCP4.5. As regards seasonal change, NPP at the mid-high latitude of Northern Hemisphere also shows an increasing trend, and the most obvious change of NPP appears in summer, especially in June. Furthermore, the response of NPP to climate change varies regionally. Relative to 1986-2005, for the middle and low scenarios (RCP2.6, RCP4.5), the range of significant impact of temperature on NPP at the mid-high latitude of Northern Hemisphere during the 21st century will gradually go down, while that of radiation and precipitation will expand. Under RCP8.5, the change of NPP at the mid-high latitude of Northern Hemisphere during the 21st century will essentially depend on temperature.