Energy Systems Division, Argonne National Laboratory, Lemont, IL, USA; Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, USA.
Energy Systems Division, Argonne National Laboratory, Lemont, IL, USA; Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, USA.
Sci Total Environ. 2019 Dec 10;695:133805. doi: 10.1016/j.scitotenv.2019.133805. Epub 2019 Aug 8.
Fossil-fuel CO emissions and their trends in eight U.S. megacities during 2006-2017 are inferred by combining satellite-derived NO emissions with bottom-up city-specific NO-to-CO emission ratios. A statistical model is fit to a collection NO plumes observed from the Ozone Monitoring Instrument (OMI), and is used to calculate top-down NO emissions. Decreases in OMI-derived NO emissions are observed across the eight cities from 2006 to 2017 (-17% in Miami to -58% in Los Angeles), and are generally consistent with long-term trends of bottom-up inventories (-25% in Miami to -49% in Los Angeles), but there are some interannual discrepancies. City-specific NO-to-CO emission ratios, used to calculate inferred CO, are estimated through annual bottom-up inventories of NO and CO emissions disaggregated to 1 × 1 km resolution. Over the study period, NO-to-CO emission ratios have decreased by ~40% nationwide (-24% to -51% for our studied cities), which is attributed to a faster reduction in NO when compared to CO due to policy regulations and fuel type shifts. Combining top-down NO emissions and bottom-up NO-to-CO emission ratios, annual fossil-fuel CO emissions are derived. Inferred OMI-based top-down CO emissions trends vary between +7% in Dallas to -31% in Phoenix. For 2017, we report annual fossil-fuel CO emissions to be: Los Angeles 113 ± 49 Tg/yr; New York City 144 ± 62 Tg/yr; and Chicago 55 ± 24 Tg/yr. A study in the Los Angeles area, using independent methods, reported a 2013-2016 average CO emissions rate of 104 Tg/yr and 120 Tg/yr, which suggests that the CO emissions from our method are in good agreement with other studies' top-down estimates. We anticipate future remote sensing instruments - with better spatial and temporal resolution - will better constrain the NO-to-CO ratio and reduce the uncertainty in our method.
利用卫星反演的 NO 排放与基于城市具体情况的 NO 与 CO 排放比相结合，推断了 2006-2017 年美国 8 个大城市的化石燃料 CO 排放及其趋势。统计模型拟合了从 Ozone Monitoring Instrument（OMI）观测到的一系列 NO 羽流，并用于计算自上而下的 NO 排放。从 2006 年到 2017 年，在 8 个城市中观察到 OMI 衍生的 NO 排放减少（迈阿密减少 17%，洛杉矶减少 58%），与基于城市具体情况的长期 NO 排放清单的趋势基本一致（迈阿密减少 25%，洛杉矶减少 49%），但存在一些年际差异。用于计算推断 CO 的城市具体 NO 与 CO 排放比是通过每年按 1×1km 分辨率分解的 NO 和 CO 排放的自下而上的清单估算得出的。在研究期间，全国范围内的 NO 与 CO 排放比下降了约 40%（我们研究的城市为-24%至-51%），这归因于由于政策法规和燃料类型转变，与 CO 相比，NO 的减少速度更快。结合自上而下的 NO 排放和自下而上的 NO 与 CO 排放比，得出了每年的化石燃料 CO 排放。推断出的基于 OMI 的自上而下的 CO 排放趋势在达拉斯为+7%，在凤凰城为-31%。2017 年，我们报告的年度化石燃料 CO 排放量为：洛杉矶 113±49Tg/yr；纽约市 144±62Tg/yr；和芝加哥 55±24Tg/yr。在洛杉矶地区进行的一项独立研究报告称，2013-2016 年的 CO 排放率为 104Tg/yr 和 120Tg/yr，这表明我们方法的 CO 排放量与其他研究的自上而下的估计值非常吻合。我们预计，未来具有更好时空分辨率的遥感仪器将更好地约束 NO 与 CO 比，并降低我们方法的不确定性。
