A global wetland methane emissions and uncertainty dataset for atmospheric chemical transport models (WetCHARTs version 1.0)
A global wetland methane emissions and uncertainty dataset for atmospheric chemical transport models (WetCHARTs version 1.0)
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DOI：
10.5194/gmd-10-2141-2017
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发表时间：
2017-06-06
影响因子：
5.1
通讯作者：
Jacob, Daniel J.
中科院分区：
文献类型：
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作者：
Bloom, A. Anthony;Bowman, Kevin W.;Jacob, Daniel J.
湿地排放仍然是全球大气甲烷（CH 4）收支不确定性的主要来源之一，这主要是由于对涝渍土壤中CH 4生产的过程控制不佳。基于过程的全球湿地甲烷排放量估计及其相关的不确定性可以为基于模型的自上而下的甲烷排放量估计提供关键的先验信息。在这里，我们构建了一个全球湿地CH 4排放模式合奏用于大气化学传输模式（WetCHARTs版本1.0）。我们的0.5度x0.5度分辨率模式集合是基于卫星衍生的地表水范围和降水再分析，（八个碳循环模型和一个受数据约束的陆地碳循环分析）和2009-2010年期间三个温度依赖性参数化;一个扩展的集合子集的基础上，降水量和数据约束的陆地碳循环分析得出的2001-2015年期间。我们将全面和扩展的模型合奏到GEOS-Chem的平均值和大气CH 4的表面测量模型进行比较;模型性能（站点水平和纬向平均异常残差）与已公布的湿地CH 4排放情景相比毫不逊色。我们发现，碳分解率和湿地范围的不确定性占80%以上的主导不确定性的时间，幅度和季节性变化的湿地甲烷排放量，虽然不确定性的温度CH 4：C的依赖是一个显着的贡献者中纬度湿地CH 4排放量的季节性变化。卫星，碳循环模型和温度依赖参数化的组合提供了一个物理上知情的结构先验的不确定性，是自上而下的湿地CH 4通量的估计是至关重要的。具体而言，我们的合奏可以提供增强信息的前CH 4排放的不确定性和误差协方差结构，以及使用后通量估计和它们的不确定性，以定量约束全球湿地CH 4排放的地球化学过程控制的手段。
Wetland emissions remain one of the principal sources of uncertainty in the global atmospheric methane (CH4) budget, largely due to poorly constrained process controls on CH4 production in waterlogged soils. Process-based estimates of global wetland CH4 emissions and their associated uncertainties can provide crucial prior information for model-based top-down CH4 emission estimates. Here we construct a global wetland CH4 emission model ensemble for use in atmospheric chemical transport models (WetCHARTs version 1.0). Our 0.5 degrees x 0.5 degrees resolution model ensemble is based on satellite-derived surface water extent and precipitation reanalyses, nine heterotrophic respiration simulations (eight carbon cycle models and a data-constrained terrestrial carbon cycle analysis) and three temperature dependence parameterizations for the period 2009-2010; an extended ensemble subset based solely on precipitation and the data-constrained terrestrial carbon cycle analysis is derived for the period 2001-2015. We incorporate the mean of the full and extended model ensembles into GEOS-Chem and compare the model against surface measurements of atmospheric CH4; the model performance (site-level and zonal mean anomaly residuals) compares favourably against published wetland CH4 emissions scenarios. We find that uncertainties in carbon decomposition rates and the wetland extent together account for more than 80% of the dominant uncertainty in the timing, magnitude and seasonal variability in wetland CH4 emissions, although uncertainty in the temperature CH4 : C dependence is a significant contributor to seasonal variations in mid-latitude wetland CH4 emissions. The combination of satellite, carbon cycle models and temperature dependence parameterizations provides a physically informed structural a priori uncertainty that is critical for topdown estimates of wetland CH4 fluxes. Specifically, our ensemble can provide enhanced information on the prior CH4 emission uncertainty and the error covariance structure, as well as a means for using posterior flux estimates and their uncertainties to quantitatively constrain the biogeochemical process controls of global wetland CH4 emissions.