摘要
草甸生态系统具有强大的碳汇功能,在全球碳循环过程中发挥着重要作用。区域尺度草甸生态系统碳通量的精准模拟,可以为揭示草地碳循环对全球变化的反馈机制提供理论依据。生态过程模型则是分析和预测区域碳平衡的重要途径。以甘南州高寒草甸生态系统为研究对象,利用参数优化后的Biome-BGC模型,模拟1979—2018年高寒草甸总初级生产力(Gross Primary Productivity,GPP)和净生态系统生产力(Net Ecosystem Productivity,NEP),以表征该区域碳收支的时空分布特征。以上述40年实测气象数据为基准,并结合第六次国际耦合模式比较计划(Coupled Model Intercomparison Project phase 6,CMIP6)中的3种共享社会经济路径(Shared Socio-economic Pathways,SSPs)情景,对甘南州2019—2100年高寒草甸碳收支进行情景模拟。结果表明:(1)参数优化后的Biome-BGC模型能较好的模拟甘南州高寒草甸GPP和NEP,且GPP模拟对比NEP的模拟效果更好;(2)甘南州高寒草甸在整个研究阶段表现为碳汇,过去40年GPP、NEP波动范围为600—1100 g C m^(-2) a^(-1)、150—300 g C m^(-2) a^(-1),GPP显著上升,NEP呈波动性上升趋势。未来暖湿化情景下,高寒草甸碳收支年际波动较大,NEP呈先上升再下降趋势,2060年前后出现极小值,年均增幅约为2.02 g C m^(-2) a^(-1),气温、降水和大气CO_(2)浓度升高共同影响该地碳收支格局;(3)季节尺度上表现为冬春季节为碳源、夏秋季节为碳汇,植被生长季固碳作用增强。年内GPP、NEP呈倒“U”型变化趋势,峰值均出现在7、8月,低温以及持续增温对碳汇具有抑制作用,生长季降水量与植被生产力呈正相关;(4)碳汇/碳源的空间分布随时间而变化,具有明显的地域差异性,总体上碳汇增长率由西南向东北递减。
Meadow ecosystems serve as significant carbon sinks,playing a crucial role in the global carbon cycle.Precise simulation of carbon fluxes in regional-scale meadow ecosystems can provide a theoretical basis for understanding the feedback mechanisms of meadow carbon cycling to global changes.Ecological process models are essential for analyzing and predicting regional carbon balance budget.This study focused on the alpine meadow ecosystem in Gannan Prefecture and utilized the parameter-optimized Biome-BGC model to simulate the gross primary productivity(GPP) and net ecosystem productivity(NEP) from 1979 to 2018,characterizing the spatiotemporal distribution characteristics of carbon budget in this region.With the benchmark of 40 years of observed meteorological data and considering three Shared Socio-economic Pathways(SSPs) from the Coupled Model Intercomparison Project phase 6(CMIP6),scenario simulations of meadow carbon balance budget in Gannan Prefecture from 2019 to 2100 were conducted.The results indicated that:the parameter-optimized Biome-BGC model performed well in simulating GPP and NEP of alpine grasslands in Gannan Prefecture,with a better performance in GPP simulation compared to NEP;(2) Alpine meadows in Gannan Prefecture behaved as a carbon sink throughout the study period,with GPP and NEP fluctuating between 600 g C m^(-2) a^(-1) and 1100 g C m^(-2) a^(-1),and between 150 g C m^(-2) a^(-1) and 300 g C m^(-2) a^(-1),respectively.GPP showed a significant increase,while NEP exhibited a fluctuating upward trend.Under future warmer and wetter scenarios,the carbon balance of alpine grasslands fluctuates greatly annually,with a trajectory that is first rising and then downward,with a very tiny NEP around 2060,and an average yearly increase of roughly 2.02 g C m^(-2) a^(-1),the carbon balance influenced jointly by temperature,precipitation and atmospheric CO_(2) concentration in this region;(3) At the seasonal scale,the winter and spring seasons act as carbon sources,while the summer and autumn seasons act as carbon sinks,with carbon sequestration during the vegetation growth season enhanced.both GPP and NEP exhibit a reverse “U”-shaped trend throughout the year,with July and August serving as the peaks.,low temperatures and ongoing warming have an inhibitory effect on carbon sequestration,while the amount of precipitation during the growing season is positively correlated with vegetation productivity;(4) Significant regional variations may be seen in the spatial distribution of carbon sinks and sources throughout time,with the development rate of carbon sinks generally decreasing from the southwest to the northeast.
作者
张盈盈
刘旻霞
潘竟虎
陈雪娇
陈友艳
张鑫
ZHANG Yingying;LIU Minxia;PAN Jinghu;CHEN Xuejiao;CHEN Youyan;ZHANG Xin(College of Geography and Environment Science,Northwest Normal University,Lanzhou 730070,China)
出处
《生态学报》
CAS
CSCD
北大核心
2024年第13期5542-5553,共12页
Acta Ecologica Sinica
基金
国家自然科学基金项目(31760135)
甘肃省自然科学基金项目(20JR10RA089)
甘肃省林业和草原科技创新与国际合作项目(KJCX2021005)
甘肃省高校产业支撑计划项目(2023CYZC-21)。
关键词
高寒草甸
碳收支
时空格局
Biome-BGC模型
参数优化
alpine meadow
carbon budget
spatial and temporal pattern
Biome-BGC model
parameter optimization
