IMHE OpenIR  > 山地表生过程与生态调控重点实验室
贡嘎山暗针叶林光能利用效率动态变化及其影响因子
Alternative TitleDynamics and influence factors of light use efficiency in a dark coniferous forest, Gongga Mountain
张元媛
Subtype硕士
Thesis Advisor朱万泽
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline自然地理学
Keyword光能利用效率 CO2通量 涡度相关 贡嘎山 暗针叶林
Abstract植被光能利用效率(LUE)反映了植被通过光合作用利用光能、吸收和固定大气中CO2的能力,是表征生态系统生产力的重要指标,也是生态系统遥感模型的关键参数。准确估算不同生态系统LUE的动态变化,确定其影响因子对定量区域和全球尺度生产力和碳收支能力极为重要。本研究利用2015年6月至2016年5月贡嘎山生态观测试验站涡度相关通量观测数据,通过数据预处理、质量控制与质量保证以及数据的插补与拆分,得到完整且连续的碳通量数据。基于贡嘎山暗针叶林生态系统CO2通量变化,结合同步监测的光合有效辐射(PAR),分析LUE动态及其与环境因子之间的关系,并与基于生物生产力估算得到的LUE进行比较。主要研究结果和结论如下:(1)贡嘎山暗针叶林CO2通量具有明显的日变化特征,呈现“U”形变化。CO2通量白天为负值,夜间为正值。在中午前后CO2通量值达到最小(即最大碳汇)。一年中,日平均CO2通量由正值变负值的时间夏季最早,冬季最晚,CO2通量由负值变为正值的时间冬季最早,夏季最晚。(2)暗针叶林净碳交换量(NEE)、生态系统呼吸(Re)和总初级生产力(GPP)具有明显的季节变化特征。2015年6月和12月NEE分别达到最大值(-46.02 gC· m-2·月-1)和最小值(-1.42 gC·m-2·月-1);Re呈现单峰变化,最大和最小值分别出现在2015年6月(84.78 gC·m-2·月-1)和2016年1月(12.82 gC·m-2·月-1);GPP最大和最小值分别出现在2015年6月(130.81 gC·m-2·月-1)与2016年1月(16.15 gC·m-2·月-1)。贡嘎山暗针叶林在观测期NEE、Re和GPP分别为-241.87、564.81 gC m-2和806.68 gC m-2,表明贡嘎山暗针叶林具有一定碳汇功能。(3)空气温度(Ta)、5 cm土壤温度(Ts5)和PAR是暗针叶林CO2通量的主要环境影响因子。Ta与CO2通量呈指数相关(R2=0.5283,P<0.01);白天CO2通量与PAR显著相关(R2=0.4373,P<0.01);夜晚CO2通量与Ts5显著相关(R2=0.4717,P<0.01)。(4)贡嘎山暗针叶林LUE具有明显日变化特征,呈现“V”型变化。早上LUE较高,中午前后达到最低值,随后开始缓慢增加。各季节、各月份LUE的日变化趋势稍有不同,表现在一天中LUE的最低值不同,以及最低值出现的时间不同。(5)5日累计光能利用效率(LUE5)出现4个不同峰值,和4个谷值。谷值分别依次出现在2015年7月和9月、2016年1月和3月,其值分别为0.023、0.021、0.009、0.016 μmol CO2·μmol photon-1。峰值分别依次出现在2015年6月、8月、10月和2016年4月,其值分别为0.0456、0.0460、0.0245、0.043 μmol CO2·μmol photon-1。月尺度光能利用效率(LUEmon)在2015年6月LUEmon最大(0.044μmol CO2·μmol photon-1),在7月降低到0.034 μmol CO2·μmol photon-1。8月LUEmon上升到0.042 μmol CO2·μmol photon-1,9月LUEmon开始下降,在2016年1月达到最低值0.015 μmol CO2·μmol photon-1,在2016年2月逐渐升高。该生态系统最大光能利用效率(LUEmax)的值为0.0454 μmol CO2·μmol photon-1。(6)贡嘎山暗针LUE日动态与Ta和PAR显著负相关。LUE季节动态与Ta、Ts5、5cm土壤湿度(Ms5)和散射辐射(DR)显著相关。LUE与Ta呈指数相关关系(R2=0.5487,P<0.01)。LUE与Ts5也存在显著相关性(R2=0.5812,P<0.01)。LUE与饱和水汽压差(VPD)和降水量(P)存在较弱相关性,但是LUE与Ms5显著相关(R2=0.4014,P<0.01)。DR与LUE具有较强的相关性(R2=0.4578,P<0.01)。(7)利用涡度相关法计算得到的暗针叶林光能利用效率(LUE1)为0.985gC·MJ-1,基于生物生产力估算得到暗针叶林光能利用效率(LUE2)为0.830gC·MJ-1,LUE1明显大于LUE2。两种方法在测量过程的不确定性可能是导致两者不同的原因。
Other AbstractThe light use efficiency(LUE) of vegetation reflects the ability of vegetation to utilize light energy, absorb and fixed CO2 in the atmosphere by photosynthesis. It is an important indicator of the productivity of the ecosystem, and also the key parameter in the numerous remote sensing model of the ecosystem. Accurately estimating the dynamic change of LUE in different ecosystems and determining the influencing factors are very important for accurate quantitative regional and global scale productivity and carbon budgets.In this study, the flux data obtained from June 2015 to May 2016 of flux observation station on Gongga mountain. Through the preprocessing of the flux observation data, quality control and quality assurance, and the interpolation and disassembly of data, the complete and continuous carbon flux data are obtained.Based on the changes in the CO2 flux of the dark coniferous forest ecosystem in Gongga mountain and the photosynthetic effective radiation (PAR) monitored synchronously, the LUE of dark coniferous forest ecosystem are calculated.The relationship between the LUE and environmental factors in dark coniferous forest was also studied.The main results and conclusions are as follows:(1) The CO2 flux of dark coniferous forest ecosystem had obvious diurnal variation characteristics and followed an U shaped carve. The CO2 flux was negative during the daytime, positive during the night, and reached its maximum around noon. The earliest time when the CO2 flux changed from positive to negative occurred in winter and the latest in summer. (2) The net carbon exchange (NEE), ecosystem respiration (Re) and gross primary productivity (GPP) of dark coniferous forest showed obvious monthly variation characteristics. The NEE reached a maximum (–46.02 gC·m-2·month-1) in June 2015 and a minimum (–1.42 gC·m-2·month-1) in January 2016. The Re had a single peak variation, and the maximum and minimum values appeared in June 2015 (84.78 gC·m-2·month-1) and January 2016 (12.82 gC·m-2·month-1). The maximum and minimum GPP values appeared in June 2015 (130.81 gC·m-2·month-1) and January 2016 (16.15 gC·m-2·month-1), respectively.The annual NEE, Re and GPP values were –241.87, 564.81 gC m-2and 806.68 gC m-2, respectively. The results showed that the dark coniferous forest on Gongga Mountain still has a strong carbon sequestration function.(3) Air temperature (Ta),5 cm soil temperature (Ts5), and PAR were the main environmental factors affecting the carbon fluxes in the dark coniferous forest . Carbon dioxide flux and Ta had an exponential correlation (R2=0.5283, P< 0.01); CO2 flux was significantly correlated with PAR during the daytime (R2=0.4373, P< 0.01); and CO2 flux was significantly correlated with Ts5 (R2 = 0.4717, P< 0.01). (4) The LUE of dark coniferous forest ecosystem had obvious diurnal variation characteristics and followed a V shaped carve. In the morning, the LUE of the ecosystem was higher, the lowest value of one day before and after noon, and increased slowly in the afternoon. The diurnal variation of LUE in different season and month is slightly different.It shows that the minimum value of LUE in a day is different, and the time of the minimum value appearance is different.(5) During the observation period from June 2015 to May 2016, the 5-days LUE(LUE5) had 4 different peaks and 4 different valleys. The valley value appeared in July 2015 and September, January 2016 and March in turn, and their values were 0.023, 0.021, 0.009 and 0.016μmolCO2 ·μmolphoton-1 respectively. The peak values were in June 2015, August, October and April 2016 in turn, and their values were 0.0456, 0.046, 0.0245 and 0.043μmolCO2 ·μmolphoton-1 respectively. The monthly light use efficiency (LUEmon) was the largest in June 2015 (0.044μmolCO2 ·μmolphoton-1). It decreased to 0.034 μmolCO2 ·μmolphoton-1 in July. In August, LUEmon rose to 0.042μmolCO2 ·μmolphoton-1.In September, LUEmon began to decline and reached a minimum in January 2016 (0.015μmolCO2 ·μmolphoton-1). LUEmon increased gradually from February 2016. The maximal light use efficiency (LUEmax ) in dark coniferous forest ecosystem is 0.0454μmolCO2 ·μmolphoton-1.(6) The daily variation of LUE in dark coniferous forest is negatively correlated with Ta and PAR. The seasonal variation of LUE in the dark coniferous forest was significantly related to Ta ,Ts5, 5cm soil moisture(Ms5) and diffuse radiation(DR). There was an exponential correlation between LUE and Ta (R2=0.5487, P<0.01). There was a significant correlation between Ts5 of LUE (R2=0.5812, P<0.01). There is a weak correlation between LUE and vapor pressure deficit(VPD) and precipitation(P), but LUE and Ms5 are significantly correlated (R2=0.4014, P<0.01). The DR has a strong correlation with LUE (R2=0.4578, P<0.01).(7) The light use efficiency (LUE1) of dark coniferous forest calculated by eddy correlation technique is 0.985gC·MJ-1. Based on biomass productivity, the light use efficiency (LUE2) of dark coniferous forest is 0.830gC·MJ-1. LUE1 was significantly greater than LUE2. The uncertainty of the two methods in the measurement process may be lead to the difference between the two results. 
Pages103
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24756
Collection山地表生过程与生态调控重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
张元媛. 贡嘎山暗针叶林光能利用效率动态变化及其影响因子[D]. 北京. 中国科学院大学,2018.
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