长江流域森林NPP模拟及其对气候变化的响应

【目的】利用LPJ模型(Lund-Potsdam-Jena model)估算长江流域森林净初级生产力(net primary productivity, NPP),研究长江流域森林NPP时空动态变化及其与气候因素的关系,为长江流域及其他地区的植被监测与生态建设提供依据。【方法】基于LPJ模型模拟的NPP数据及气象资料,对长江流域1982—2013年森林NPP的空间分布和时空动态变化趋势进行分析,采用线性回归分析法分别以时间为自变量和NPP为因变量进行趋势检验,利用相关性分析法分析长江流域森林NPP与气象因子之间的关系。【结果】①长江流域1982—2013年森林年均NPP值为530.41 g/(m²·a),最高值出现在2002年,森林NPP值为578.55 g/(m²·a);最低值出现在1989年,森林NPP值为491.24 g/(m²·a)。②长江流域森林NPP的空间分布由东南沿海向西北逐渐减小,长江中下游森林NPP高于长江上游,森林NPP空间分布格局与水热条件分布格局相一致,长江流域东南部水热条件良好,能够满足植被生长和发展的需要,植被生产力比较高;西北部由于水热条件比较差,不利于植被生长,生产力低下。③长江流域大部分地区森林NPP与气温和降水为正相关关系,森林NPP与气温呈显著正相关,气温与森林NPP之间的相关性强于降水与森林NPP之间的相关性。【结论】长江流域森林NPP呈自东南向西北减少的趋势,且随时间呈波动上升趋势;气候对森林NPP具有显著影响,气温是影响森林NPP的主导因素。

Forest NPP simulation in the Yangtze River Basin and its response to climate change

【Objective】The Lund-Potsdam-Jena(LPJ)model was used to evaluate the forest net primary productivity(NPP)in the Yangtze River Basin and to study the temporal and spatial dynamic changes in the forest NPP and its relationship with climate factors.This can provide a reference for vegetation monitoring and ecological reconstruction in the Yangtze River Basin and other areas.【Method】The NPP simulated by the LPJ model and meteorological data were used to evaluate the spatial distribution and spatio-temporal variation trend of the forest NPP in the Yangtze River Basin from 1982 to 2013.The linear regression analysis method was used to test the trend,with time as the independent variable and the vegetation variable(i.e.,NPP in our study)as the dependent variable.The correlation analysis was used to analyze the relationship between the forest NPP and meteorological factors in the Yangtze River Basin.【Result】①The annual average forest NPP value in the Yangtze River Basin from 1982 to 2013 was 530.41 g/(m²·a),and the highest forest NPP value was 578.55 g/(m²·a)in 2002.The lowest forest NPP occurred in 1989,with a value of 491.24 g/(m²·a).②The spatial distribution of the forest NPP in the Yangtze River Basin decreased gradually from the southeast coast to the northwest,and the forest NPP in the middle and lower reaches of the Yangtze was higher than that in the upper Yangtze reaches.The spatial distribution pattern of the forest NPP was consistent with the distribution pattern of water and heat conditions.The water and heat conditions in the southeast of the Yangtze River Basin could meet the needs of vegetation growth and development,and the vegetation productivity was relatively high.The poor water and heat conditions in the northwest were not conducive to vegetation growth,which showed low productivity.③The forest NPP was positively correlated with temperature and precipitation in most areas of the Yangtze River Basin,and it showed a significant positive correlation with temperature.Moreover,the correlations between the forest NPP and temperature were higher than those of the forest NPP and precipitation.【Conclusion】The forest NPP in the Yangtze River Basin presented a decreasing trend from southeast to northwest,and showed a rising trend of fluctuation with time.Climate had a significant influence on forest NPP,and temperature was the leading factor affecting the forest NPP.