基于BEPS模型的云南省碳源/汇时空特征及其适用性分析

Spatio⁃temporal characteristics and applicability of carbon source/sink in Yunnan Province based on BEPS model

净初级生产力(NPP)和净生态系统生产力(NEP)是估算陆地生态系统碳源/汇的重要指标,云南为我国碳汇的主要区域之一,开展云南NPP和NEP时空变化特征分析对科学评估陆地生态系统碳源/汇功能,以及开展碳排放交易具有重要意义。基于BEPS模型1981-2019年NPP和NEP产品,采用线性趋势分析、文献对比等方法,研究云南NPP和NEP时空变化特征及其在云南的适用性。结果表明:(1)1981-1999年云南NPP和NEP呈水平波动,2000年后云南NPP和NEP呈明显波动上升趋势,2000-2019年云南NPP高值区域主要分布在西部和南部,而NEP高值区则主要分布在东部和西部局部地区;(2)2000-2019年云南NPP和NEP除西北部部分地区为下降趋势外,其余大部地区为上升趋势;(3)云南NPP峰值出现在7、8月,谷值出现在2月,NEP峰值出现月份与NPP基本相同,但谷值出现月份较NPP滞后1-3个月,6-10月是云南碳汇的主要月份;(4)BEPS模型估算的NPP与目前广泛应用的CASA和遥感模型结果较为一致,时空变化特征与云南生态恢复措施和气候特征吻合,其估算的NEP与陆地生物圈模型(IBIS)模型和中国通量观测研究联盟(ChinaFLUX)碳水通量观测数据较为接近,时空变化大部地区与云南生态恢复措施和气候特征基本吻合,表明BEPS模型在云南具有较好的适用性。

Net primary productivity(NPP)and net ecosystem productivity(NEP)are important indicators for estimating the carbon source/sink of terrestrial ecosystems.NEP is the net carbon absorption of vegetation ecosystems,which can quantitatively describe the carbon source/sink capacity of vegetation ecosystems.It is great significance to analyze the spatiotemporal variation characteristics of NPP and NEP for scientific assessment of carbon source/sink function of terrestrial ecosystem and carbon emission trading,because Yunnan is one of the main regions of carbon sink in China.Based on the boreal ecosystem productivity simulator(BEPS)of gross primary productivity(GPP),NPP and NEP products from 1981 to 2019,the spatiotemporal variation characteristics of NPP and NEP and their applicability in Yunnan were studied by using linear trend analysis,literature comparison,and other methods.The results show that:(1)the NPP and NEP in Yunnan fluctuated horizontally from 1981 to 1999,and increased significantly after 2000.The average values of NPP and NEP per unit area from 2000 to 2019 were 739.0 gC/m^(2) and 70.1 gC/m^(2),respectively,with a total amount of 0.291 Pg C/a and 0.028 Pg C/a.Compared to 1981 to 1999,it increased by 12.4%and 150.4%respectively.The high value areas of NPP were mainly distributed in the west and south,most regions had an annual average NPP of over 700 gC/m^(2),while the NEP were mainly distributed in the eastern and partial western from 2000 to 2019.(2)During the 2000 to 2019,most areas of Yunnan NPP and NEP showed an upward trend,except for the northwest,where NPP showed a downward trend.(3)The peak value of NPP occurred in July or August,and the valley value occurred in February.The month of NEP peak occurrence was basically the same as NPP,but the valley month was delayed 1-3 months.June to October were the main months of carbon sink.(4)The NPP simulated by the BEPS model was consistent with the widely used Carnegie-Ames-Stanford Approach(CASA)and remote sensing models,and the spatiotemporal change characteristics were conformed with the ecological restoration measures and climate characteristics of Yunnan.The simulated NEP was same as the integrated biosphere simulator(IBIS)and the carbon and water flux observation data of ChinaFLUX.Most of the spatiotemporal changes ware also basically consistent with the ecological restoration measures and climate characteristics of Yunnan,indicating that the BEPS model had good applicability in Yunnan.