气候变化下中国潜在自然植被生态系统碳储量动态

Dynamics of ecosystem carbon storage of potential natural vegetation in China under climate change

陆地生态系统固碳是减缓大气CO_(2)浓度升高的重要途径,了解气候变化下潜在自然植被生态系统碳储量(ECS)有利于区域土地管理政策的制定。该研究基于遗传算法对LPJ-GUESS模型的敏感参数进行校准,使用降尺度的气候数据驱动模型,结合Mann-Kendall趋势检验、Sen’s斜率估计方法和偏相关分析法,分析2001-2100年中国ECS的时空格局、趋势变化特征及气候主导因子。结果表明:1)校准后的LPJ-GUESS模型模拟ECS的纳什效率系数和皮尔逊相关系数分别为0.751、0.901,表明LPJ-GUESS模型可以较好地模拟中国ECS。2)2001-2020年,中国潜在自然植被ECS由东南向西北递减,总量为156.06 Pg,其中植被、凋落物、土壤碳储量分别占34.2%、1.9%、63.8%。相比于2001-2020年,2081-2100年ECS具有相似的空间分布,ECS总量预计增加0.51-11.16 Pg;2001-2020年和2021-2100年,中国潜在自然植被ECS的增加速率分别为8.5 g·m^(-2)·a^(-1)、3.7-21.0 g·m^(-2)·a^(-1)。3)2021-2100年中国东南部、内蒙古高原、青藏高原等地区ECS显著增加(37-44 g·m^(-2)·a^(-1)),云贵高原南部、两广丘陵等地区ECS显著减少(45-72 g·m^(-2)·a^(-1))。(4)不同区域的气候主导因子不同:气温在中国西北地区主导ECS变化;受区域干旱程度影响,ECS与降水量的相关性由东南向西北递增;辐射在高纬度、高海拔地区主导ECS变化;在中国47.9%-56.1%的区域CO_(2)浓度主导ECS变化。

Aims Carbon sequestration in terrestrial ecosystems is one of the important ways to slow down the rise of atmospheric CO_(2)concentration.Therefore,understanding the natural vegetation ecosystems carbon storage(ECS)in response of future climate change is critical for making of regional land management policies.Methods In this study,the sensitive parameters of LPJ-GUESS model are calibrated based on genetic algorithm.Using the downscale climate data-driven model,combined with Mann Kendall test,Sen’s slope estimation and partial correlation analysis,the temporal and spatial patterns,trend change characteristics and climate dominant factors of China’s ECS from 2001 to 2100 are analyzed.Important findings The Nash-Sutcliffe efficiency coefficient and Pearson correlation coefficient of the calibrated LPJ-GUESS model in simulating ECS are 0.751 and 0.901,respectively,indicating that the LPJ-GUESS model can simulate China’s ECS well.During 2001-2020,China’s ECS decreased from southeast to northwest,with a total amount of 156.06 Pg.Vegetation,litter and soil carbon storage accounted for 34.2%,1.9%and 63.8%of total ECS,respectively.The ECS in 2081-2100 shows similar spatial pattern with that in historical periods.The total amount of ECS at the end of this century are expected to increase by 0.51-11.16 Pg.The growth rates of China’s ECS was 8.5 g·m^(-2)·a^(-1)and 3.7-21.0 g·m^(-2)·a^(-1)during 2001-2020 and 2021-2100,respectively.During 2021-2100,significant increases of ECS are observed in southeast China,Nei Mongol Plateau,Qingzang Plateau(37-44 g·m^(-2)·a^(-1)),while obvious decreases(45-72 g·m^(-2)·a^(-1)),in the southern Yunnan-Guizhou Plateau,hilly areas in Guangxi and Guangdong.In northwest China,temperature is the dominant factor affecting ECS.The influences of precipitation on ECS are strengthened from the southeast to northwest.In high latitude and high-altitude areas,radiation is the dominant factor of ECS.CO_(2)plays the most important role on ECS across about 47.9%-56.1%of China’s area.