基于多模型的森林—草原交错带碳动态模拟研究

发布时间：2018-03-08 07:45

本文选题：森林-草原交错带　切入点：CENTURY模型　出处：《内蒙古农业大学》2017年博士论文　论文类型：学位论文

【摘要】：草地生态系统的碳动态研究在全球变化研究领域中具有非常重要的地位。准确评估草地生态系统碳源/汇关系及其对气候变化和人类干扰的响应和反馈作用是一个重大的科学问题。森林-草原交错带是生态交错带中受人类活动干扰最为敏感的区域之一,具有对气候变化的潜在指示作用。本研究以赛罕乌拉自然保护区这一典型森林-草原交错带为研究对象,针对该区域的草地生态系统,利用生物地球化学循环模型(CENTURY模型和DNDC模型),将样地实测数据、站点观测数据、遥感影像和模型模拟耦合在一起,进行了一系列的参数本地化、模型验证和分析,将验证好的模型进一步分析森林-草原交错带草地生态系统在气候变化和自然保护条件下的碳动态情况。主要结论如下:(1)经过大量参数本地化后的CENTURY模型、DNDC模型能够很好地反映研究区的碳动态,都通过了实测数据、文献数据的多方位检验和验证。在模拟精度方面,以日为时间步长的DNDC模型要比以月为时间步长的CENTURY模型精度高,在一些动态分析上更具有优势。(2)在过去的55年中,研究区地上生物量为71.01gC/m2,地下生物量为601.96gC/m2,总生物量为672.97gC/m2。研究区地上生物量和总生物量的变化趋势与年降水量一致,与年平均气温关系不明显。降水是影响地上生物量和总生物量的重要气象因子。(3)自1961年以来,研究区单位面积碳储量总体呈上升趋势,1968年、1988年和2006年出现急剧下降,随后持续上升。总碳储量密度为73295.41kgC/hm2,其中,植被碳密度为6729.69kgC/hm2,土壤碳密度(0-50cm)为66565.73kgC//hm2,总碳储量为 0.22TgC。(4)研究区55年当中,共有17年为碳源,其余均为碳汇。1961-2015年共增加碳蓄积22108.24kgC/hm2,平均每年增汇量为401.96kgC/hm2。研究发现,碳汇与地上生物量、降水量、总生物量、地下生物量、相对湿度为极显著正相关(p0.01),与地上生物量和降水量的相关系统分别达到0.785和0.756;碳汇与潜在蒸散量和日平均气温为极显著负相关(p0.01),相关系数分别为-0.637和-0.395。(5)基于CENTURY模型预测未来30-50年,研究区地上、地下生物量和单位面积土壤碳储量呈略增态势。
[Abstract]:The carbon dynamics of grassland ecosystem plays a very important role in the field of global change. It is important to evaluate accurately the carbon source / sink relationship of grassland ecosystem and its response and feedback to climate change and human disturbance. The forest-grassland ecotone is one of the most sensitive areas of the ecotone affected by human activity. This study focused on the typical forest- grassland ecotone of the Sahanula Nature Reserve, and aimed at the grassland ecosystem of the region. By using biogeochemical cycle model (CENTURY) and DNDC model, a series of parameter localization, model verification and analysis have been carried out by coupling the measured data, station observation data, remote sensing image and model simulation. The verified model will be used to further analyze the carbon dynamics of grassland ecosystems in the forest- grassland ecotone under the conditions of climate change and natural conservation. The main conclusions are as follows: (1) the CENTURY model with a large number of localized parameters is a DNDC model. Can well reflect the carbon dynamics of the study area, In terms of simulation accuracy, the DNDC model with day as time step is more accurate than CENTURY model with month as time step. In the past 55 years, the aboveground biomass was 71.01 g C / m ~ (2), the underground biomass was 601.96 g C / m ~ (2), the total biomass was 672.97 g C / m ~ (2). The variation trend of aboveground biomass and total biomass was consistent with the annual precipitation. Precipitation is an important meteorological factor affecting aboveground biomass and total biomass. Since 1961, carbon storage per unit area in the study area has been on the rise, and decreased sharply in 1968, 1988 and 1988. The total carbon storage density was 73295.41 kg C / hm 2, in which the vegetation carbon density was 6729.69 kg C / hm 2, the soil carbon density was 0-50 cm) and the total carbon storage was 66565.73 kg C / r 路hm 2, and the total carbon storage was 0.22 TgC.4) in the study area, there were 17 years of carbon sources in the study area. The rest were carbon sinks. 1961-2015. The total increase in carbon stock was 22108.24kgC / hm ~ (2), and the average annual increase was 401.96 kg C / hm ~ (2). The study found that carbon sink and aboveground biomass, precipitation, total biomass, underground biomass, The correlation system between relative humidity and aboveground biomass and precipitation was 0.785 and 0.756, respectively, and the correlation coefficient between carbon sink and potential evapotranspiration and daily mean temperature was extremely significant negative correlation, the correlation coefficient was -0.637 and -0.395.55) based on CENTURY model. For the next 30-50 years, Aboveground biomass and soil carbon storage per unit area in the study area increased slightly.
【学位授予单位】：内蒙古农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q948

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