A multitower measurement network estimate of California's methane emissions
A multitower measurement network estimate of California's methane emissions
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加州甲烷排放量的多塔测量网络估算
DOI：
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发表时间：
2013
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通讯作者：
M. Fischer
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作者：
Seongeun Jeong;Y. Hsu;A. Andrews;L. Bianco;P. Vaca;J. Wilczak;M. Fischer
我们利用加州中央山谷五个地点不同季节(2010年9月至2011年6月)的大气观测，对甲烷(CH4)排放进行了分析。空间区域和源部门的CH4排放量是通过将测量的CH4混合比与基于两个0.1°CH4(季节变化的“特定加利福尼亚”(加利福尼亚温室气体排放测量，CALGEM)和静态全球排放模型(全球大气研究排放数据库，第42版，EDGAR42))的运输模型(天气研究和预报和随机时间反转拉格朗日运输)预测进行比较来估计的。特定地区的贝叶斯分析表明，对于加州中央山谷，基于CALGEM和EDGAR42的反演提供了一致的年度CH4排放总量(32.87 ± 2.09对31.60 ± 2.17 TG CO2eq yr−1；假设地区之间的误差不相关，68%的可信区间(CI))。总而言之，在加州所有地区，优化的甲烷排放在基于CALGEM和基于EDGAR42的反演之间仅略有一致(48.35 ± 6.47vs64.97 ± 11.85 TG CO2eq)，因为沿海城市地区的排放(EDGEM的垃圾和天然气排放比CALGEM高得多)不受测量的强烈限制。将我们的结果与最近对南海岸气盆的研究结果相结合，将估计范围缩小到43-57 Tg CO2eq yr−1(比当前州清单高1.3%-1.8%)。这些结果表明，将农村和城市的测量结合起来，将是验证加州甲烷排放总量未来变化的必要手段。
We present an analysis of methane (CH4) emissions using atmospheric observations from five sites in California's Central Valley across different seasons (September 2010 to June 2011). CH4 emissions for spatial regions and source sectors are estimated by comparing measured CH4 mixing ratios with transport model (Weather Research and Forecasting and Stochastic Time‐Inverted Lagrangian Transport) predictions based on two 0.1° CH4 (seasonally varying “California‐specific” (California Greenhouse Gas Emission Measurements, CALGEM) and a static global (Emission Database for Global Atmospheric Research, release version 42, EDGAR42)) prior emission models. Region‐specific Bayesian analyses indicate that for California's Central Valley, the CALGEM‐ and EDGAR42‐based inversions provide consistent annual total CH4 emissions (32.87 ± 2.09 versus 31.60 ± 2.17 Tg CO2eq yr−1; 68% confidence interval (CI), assuming uncorrelated errors between regions). Summing across all regions of California, optimized CH4 emissions are only marginally consistent between CALGEM‐ and EDGAR42‐based inversions (48.35 ± 6.47 versus 64.97 ± 11.85 Tg CO2eq), because emissions from coastal urban regions (where landfill and natural gas emissions are much higher in EDGAR than CALGEM) are not strongly constrained by the measurements. Combining our results with those from a recent study of the South Coast Air Basin narrows the range of estimates to 43–57 Tg CO2eq yr−1 (1.3–1.8 times higher than the current state inventory). These results suggest that the combination of rural and urban measurements will be necessary to verify future changes in California's total CH4 emissions.