TransCom N2O model inter-comparison - Part 2: Atmospheric inversion estimates of N2O emissions
TransCom N2O model inter-comparison - Part 2: Atmospheric inversion estimates of N2O emissions
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DOI：
10.5194/acp-14-6177-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Bousquet, P.
中科院分区：
文献类型：
--
作者：
Thompson, R. L.;Ishijima, K.;Bousquet, P.
本研究探讨N2 O排放量估计从五个不同的大气逆温框架的基础上化学传输模型（CTM）。这五个框架在CTM、气象数据、先验不确定性和反演方法的选择上有所不同，但使用相同的先验排放和观测数据集。后模拟的大气N2 O摩尔分数进行比较，观察，以评估反演的性能，并帮助诊断问题的模拟运输。此外，2006年至2008年的平均排放量进行了比较的空间分布和季节性。总体而言，有一个很好的协议之间的反演平均全球总排放量，范围从16.1至18.7 TgN年（-1），是与以前的估计一致。海洋排放量占全球总量的31%至38%，而此前的估计为24%至38%。来自北方中高纬度地区的排放可能更为重要，在北方半球，排放一直从热带和亚热带地区转移到中高纬度地区; 0- 30 A度N与30- 90 A度N的排放比率为1.5至1.9，而先前的估计为2.9至3.0。在南亚和东亚以及热带和南美洲地区，逆温之间的差异最大，这是因为这些地区的观测限制较差，而且模拟的输送差异很大，特别是半球间的交换率和热带对流混合。N2 O排放的季节性周期的估计也对模拟热带和南部热带外平流层到对流层输送的误差敏感。总体而言，与以前的独立研究相比，结果显示全球和区域排放量趋同。
This study examines N2O emission estimates from five different atmospheric inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation data set. The posterior modelled atmospheric N2O mole fractions are compared to observations to assess the performance of the inversions and to help diagnose problems in the modelled transport. Additionally, the mean emissions for 2006 to 2008 are compared in terms of the spatial distribution and seasonality. Overall, there is a good agreement among the inversions for the mean global total emission, which ranges from 16.1 to 18.7 TgN yr(-1) and is consistent with previous estimates. Ocean emissions represent between 31 and 38% of the global total compared to widely varying previous estimates of 24 to 38%. Emissions from the northern mid- to high latitudes are likely to be more important, with a consistent shift in emissions from the tropics and subtropics to the mid- to high latitudes in the Northern Hemisphere; the emission ratio for 0-30A degrees N to 30-90A degrees N ranges from 1.5 to 1.9 compared with 2.9 to 3.0 in previous estimates. The largest discrepancies across inversions are seen for the regions of South and East Asia and for tropical and South America owing to the poor observational constraint for these areas and to considerable differences in the modelled transport, especially inter-hemispheric exchange rates and tropical convective mixing. Estimates of the seasonal cycle in N2O emissions are also sensitive to errors in modelled stratosphere-to-troposphere transport in the tropics and southern extratropics. Overall, the results show a convergence in the global and regional emissions compared to previous independent studies.