Use of a process-based model for assessing the methane budgets of global terrestrial ecosystems and evaluation of uncertainty
Use of a process-based model for assessing the methane budgets of global terrestrial ecosystems and evaluation of uncertainty
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DOI：
10.5194/bg-9-759-2012
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发表时间：
2012-01-01
期刊：
影响因子：
4.9
通讯作者：
Inatomi, M.
中科院分区：
文献类型：
--
作者：
Ito, A.;Inatomi, M.
我们评估了全球陆地预算的甲烷（CH 4），通过使用一个基于过程的地球化学模型（VISIT）和库存数据的组成部分的预算，没有包括在模型中。该模型模拟了湿地、稻田、生物质燃烧和植物的排放，以及高地土壤的氧化消耗。采用清单办法评估了反刍家畜和白蚁的排放量。这些CH 4流量是针对1901年至2009年模型的每个0.5度x 0.5度网格单元进行估计的，同时考虑了大气成分、气象因素和土地利用变化。通过使用不同参数化方案和输入数据（例如，不同的湿地地图和排放因子）。从1996年到2005年，在1152次模拟的基础上估计了全球陆地CH 4的平均收支，发现陆地生态系统是308.3 +/- 20.7 Tg CH 4 yr（-1）的净来源。湿地和牲畜反刍动物排放是主要来源。我们的模拟结果表明，源和汇分布在地球的陆地表面高度不均匀。还评估了陆地收支的季节性和年际变化。陆地源净排放量增加的趋势及其与温度变率的关系意味着，由于未来气候变化，陆地CH 4反馈将发挥越来越重要的作用。
We assessed the global terrestrial budget of methane (CH4) by using a process-based biogeochemical model (VISIT) and inventory data for components of the budget that were not included in the model. Emissions from wetlands, paddy fields, biomass burning, and plants, as well as oxidative consumption by upland soils, were simulated by the model. Emissions from ruminant livestock and termites were evaluated by using an inventory approach. These CH4 flows were estimated for each of the model's 0.5 degrees x 0.5 degrees grid cells from 1901 to 2009, while accounting for atmospheric composition, meteorological factors, and land-use changes. Estimation uncertainties were examined through ensemble simulations using different parameterization schemes and input data (e.g., different wetland maps and emission factors). From 1996 to 2005, the average global terrestrial CH4 budget was estimated on the basis of 1152 simulations, and terrestrial ecosystems were found to be a net source of 308.3 +/- 20.7 Tg CH4 yr(-1). Wetland and livestock ruminant emissions were the primary sources. The results of our simulations indicate that sources and sinks are distributed highly heterogeneously over the Earth's land surface. Seasonal and interannual variability in the terrestrial budget was also assessed. The trend of increasing net emission from terrestrial sources and its relationship with temperature variability imply that terrestrial CH4 feedbacks will play an increasingly important role as a result of future climatic change.