Supplementary material from "<i>δ</i><sup>13</sup>C methane source signatures from tropical wetland and rice field emissions
The atmospheric methane (CH<sub>4</sub>) burden is rising sharply, but the causes are... more The atmospheric methane (CH<sub>4</sub>) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH<sub>4</sub> emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new <i>δ</i><sup>13</sup>C<sub>CH<sub>4</sub></sub> signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. In summary, tropical wetland <i>δ</i><sup>13</sup>C<sub>CH<sub>4</sub></sub> generally range between −62 and −52‰ and rice paddies between −59 and −57‰. Long-term monitoring of <i>δ</i><sup>13</sup>C<sub>CH<sub>4</sub></sub> in ambient air has been conducted at...
Supplementary Tables and Figures from <i>δ</i><sup>13</sup>C methane source signatures from tropical wetland and rice field emissions
Detailed site location information along with extra information on Botswana and Bolivian long-ter... more Detailed site location information along with extra information on Botswana and Bolivian long-term time series data
Determining UK regional isotopic source signatures of methane using long-term records
&amp;lt;p&amp;gt;Long term records are vital for understanding the way in which our envir... more &amp;lt;p&amp;gt;Long term records are vital for understanding the way in which our environment is changing. &amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;A significant rise in atmospheric methane began in 2007 and has accelerated thereafter, particularly since 2014. This trend was observed globally and was coupled with a sustained isotopic shift to values more depleted in &amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C (more negative &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;). Currently, there is no consensus as to why these observations have occurred. However, long term methane isotopic measurements can provide information about changes in the source mix of this important greenhouse gas. Here, long term records of both methane mole fraction and &amp;amp;#160;&amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; from 5 sites across the UK are presented, showing an increase in CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; and a decrease in &amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C from 2007, similar to those recorded globally, but at the regional-local scale. The approximately weekly in-situ measurements offer an insight into both suburban and background regions of the UK.&amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;A method for isotopic discrimination from longer term atmospheric measurements of CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and &amp;amp;#160;&amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; as outlined by Miller and Tans (2003) is utilised in this work. Miller-Tans analysis allows for the explicit specification of background values, vital when dealing with long term records due to both seasonal, local, regional and global background variations in atmospheric CH&amp;lt;sub&amp;gt;4 &amp;lt;/sub&amp;gt;and &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4.&amp;lt;/sub&amp;gt; &amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;When applying the Miller-Tans method to the long-term data from UK sites, as expected, the heaviest &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; source signatures, which are associated with industrial sources such as gas leaks, are observed for the suburban sites, and biogenic, lighter, sources for the background sites. The methane source distribution is compared to results from mobile measurements carried out at Royal Holloway, University of London and to the UK National Atmospheric Emissions Inventory (NAEI).&amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;From the initial results, it seems that there is a larger proportion of thermogenic/pyrogenic emissions in this data compared to the NAEI inventory. At all sites, there has been a post 2006 decline in &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;. Using the Miller Tans method, it is possible to calculate bulk regional source signatures which highlight a distinction between rural and suburban emissions, in general agreement with the NAEI.&amp;lt;/p&amp;gt;
We present a novel high-resolution inverse modelling system ("FLEXVAR") based on FLEXPART-COSMO b... more We present a novel high-resolution inverse modelling system ("FLEXVAR") based on FLEXPART-COSMO back trajectories driven by COSMO meteorological fields at 7 km × 7 km resolution over the European COSMO-7 domain and the four-dimensional variational (4DVAR) data assimilation technique. FLEXVAR is coupled offline with the global inverse modelling system TM5-4DVAR to provide background mole fractions ("baselines") consistent with the global observations assimilated in TM5-4DVAR. We have applied the FLEXVAR system for the inverse modelling of European emissions in 2018 using 24 stations with in situ measurements, complemented with data from five stations with discrete air sampling (and additional stations outside the European COSMO-7 domain used for the global TM5-4DVAR inversions). The sensitivity of the FLEXVAR inversions to different approaches to calculate the baselines, different parameterizations of the model representation error, different settings of the prior error covariance parameters, different prior inventories and
CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources... more CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources (emissions to the atmosphere) and sinks (removal from the atmosphere) of carbon dioxide around the world. CarbonTracker uses atmospheric CO2 observations from a host of collaborators and simulated atmospheric transport to estimate these surface fluxes of CO2. This release of CarbonTracker Near Real-Time, CT-NRT.v2021-3, provides global estimates of surface-atmosphere fluxes of CO2 from April 2018 through August 2020.
CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources... more CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources (emissions to the atmosphere) and sinks (removal from the atmosphere) of carbon dioxide around the world. CarbonTracker uses atmospheric CO2 observations from a host of collaborators and simulated atmospheric transport to estimate these surface fluxes of CO2. This release of CarbonTracker, CT2019B, provides global estimates of surface-atmosphere fluxes of CO2 from January 2000 through December 2018.
Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1957-2020; obspack_co2_1_GLOBALVIEWplus_v7.0_2021-08-18
This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 20... more This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 2014; www.earth-syst-sci-data.net/6/375/2014/]. The framework is designed to bring together atmospheric greenhouse gas (GHG) observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. ObsPack products are intended to support GHG budget studies and represent a new generation of cooperative value-added GHG data products. This product includes 524 atmospheric carbon dioxide datasets derived from observations made by 70 laboratories from 21 countries. Data for the period 1957-2020 (where available) are included.
Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1957-2019; obspack_co2_1_GLOBALVIEWplus_v6.0_2020-09-11
A full list of all creators for this product can be found at www.esrl.noaa.gov/gmd/ccgg/obspack/p... more A full list of all creators for this product can be found at www.esrl.noaa.gov/gmd/ccgg/obspack/providerlist/obspack_co2_1_GLOBALVIEWplus_v6.0_2020-09-11.html. This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 2014; www.earth-syst-sci-data.net/6/375/2014/]. The framework is designed to bring together atmospheric greenhouse gas (GHG) observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. ObsPack products are intended to support GHG budget studies and represent a new generation of cooperative value-added GHG data products. This product includes 471 atmospheric carbon dioxide datasets derived from observations made by 54 laboratories from 21 countries. Data for the period 1957-2019 (where available) are included.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2021
The atmospheric methane (CH 4 ) burden is rising sharply, but the causes are still not well under... more The atmospheric methane (CH 4 ) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH 4 emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new δ 13 C CH 4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring of δ 13 C CH 4 in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH 4 sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH 4 to the atmosphere during periods of reduced wetland exte...
Volatile organic compounds (VOCs) and oxygenated VOCs (OVOCs) were measured in Ho Chi Minh City (... more Volatile organic compounds (VOCs) and oxygenated VOCs (OVOCs) were measured in Ho Chi Minh City (HCMC) and Hanoi, the two largest and most populous cities in Vietnam. The purpose of this study is to better understand the VOC atmospheric composition and their role in ground-level ozone formation. Online measurements of a wide range of VOCs and other pollutants were conducted using numerous instruments during different seasons (dry and rainy) in HCMC and Hanoi (spring). Our results show that the mean mixing ratio of total measured VOCs in Hanoi was 80.8 ± 40.7 ppb (mean ± standard deviation), and was similar to that observed during the rainy season (75.2 ± 44.8 ppb) in HCMC. During the dry season campaign in HCMC, which was coincident with the Hanoi campaign, total VOC was around 50% lower (40.7 ± 19.5 ppb), largely a result of increased planetary boundary layer (PBL) height and the direction of the prevailing wind. VOC profiles in both cities were dominated by alkanes (31-35%) and OVOCs (27-33%) and the proportion of alkenes (13-17%) and aromatics (12-19%) were comparable. Similarities in diurnal variation for most VOC species (except for isoprene) are seen in both cities with two clear peaks during the morning (7:00-8:00 am) and evening (18:00 pm) rush hours, as observed for vehicular-combustion tracers (acetylene and CO). Comparisons of the ambient ratios of paired VOCs, namely i/n-pentane, and toluene/benzene, with those reported in motorcycle exhaust, roadside and gasoline samples indicate that motorcycle-related emission is likely a major contributor to VOC pollution. According to the propylene-equivalent concentration (PE conc.) and maximum incremental reactivity (MIR) methods, alkenes and aromatics were determined to be the main contributors to reactivity and ozone potential formation. Furthermore, the initial mixing ratio of VOC species was estimated based on the photochemical age method. The consumed VOCs (initial VOCs minus measured VOCs) has a similar variation trend to ground-level ozone, and a good correlation is observed in HCMC. In contrast, this result was not seen in Hanoi despite relatively high levels of PE conc. and MIR.
Philosophical Transactions of the Royal Society B: Biological Sciences, 2020
During the summer of 2018, a widespread drought developed over Northern and Central Europe. The i... more During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO 2 ) exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO 2 seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO 2 gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO 2 cycles from 48 European stations were available for 2017 and 2018. Earlie...
Sarah Moller (4) , James Lee (4) , Stephane Bauguitte (5) , Stewart Vaughan (6) , Will Morgan (7)... more Sarah Moller (4) , James Lee (4) , Stephane Bauguitte (5) , Stewart Vaughan (6) , Will Morgan (7) , Bin Ouyang (8) , Oliver Kennedy (8) , Rod Jones (8) , Grant Forster (9) , Claire Reeves (9)
Atmospheric Chemistry and Physics Discussions, 2014
Wet deposition is the dominant mechanism for removing black carbon (BC) from the atmosphere, and ... more Wet deposition is the dominant mechanism for removing black carbon (BC) from the atmosphere, and is key in determining its atmospheric lifetime, vertical gradient and global transport. Despite the importance of BC in the climate system, especially in terms of its ability to modulate the radiative energy budget, there are few quantitative case studies of wet removal in ambient environments. We present a case study of BC wet removal by examining aerosol size distributions and BC coating properties sampled in three Canadian boreal biomass burning plumes, one of which passed through a precipitating cloud. In this plume, the largest and most coated BC particles were found to be preferentially removed, suggesting that nucleation scavenging was the likely dominant mechanism. Calculated mass absorption coefficient (MAC) in the plumes showed no significant variation, as the shifts to smaller BC cores and thinner coatings had opposing effects. Similarly, calculated single-scatter albedo (SSA)...
Atmospheric peroxy nitrates (PNs or RO2NO2), alkyl nitrates (ANs or RONO2) and nitric acid (HNO 3... more Atmospheric peroxy nitrates (PNs or RO2NO2), alkyl nitrates (ANs or RONO2) and nitric acid (HNO 3) are high oxides of nitrogen formed as intermediate or final products in the oxidation chains of volatile organic compounds (VOC) that, in the presence of nitrogen oxides (NO x = NO + NO 2), may produce ozone (O 3). The main branch of the reaction between RO 2 and NO produce NO 2 , which upon photolysis generates O 3 , while a minor branch makes ANs; therefore the alkyl nitrate concentrations are generally considered as a Published by Copernicus Publications on behalf of the European Geosciences Union.
We describe the design and execution of the BOR-TAS (Quantifying the impact of BOReal forest fire... more We describe the design and execution of the BOR-TAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) experiment, which has the overarching objective of understanding the chemical aging of air masses that contain the emission products from seasonal boreal wildfires and how these air masses subsequently impact downwind atmospheric composition. The central focus of the experiment was a twoweek deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA) over eastern Canada, based out of Published by Copernicus Publications on behalf of the European Geosciences Union.
Nghiên cứu thực hiện quan trắc liên tục các khí nhà kính carbon dioxide (CO 2), nitrous oxide (N ... more Nghiên cứu thực hiện quan trắc liên tục các khí nhà kính carbon dioxide (CO 2), nitrous oxide (N 2 O), methane (CH 4) và carbon monoxide (CO) từ tháng 10 năm 2018 đến tháng 4 năm 2019 ở Thành phố Hồ Chí Minh (TP.HCM). Các khí nhà kính được đo bằng thiết bị Los Gatos Research với độ phân giải cao. Nghiên cứu này là một trong những nghiên cứu đầu tiên đo đạc các khí nhà kính với độ phân giải thời gian cao ở TP.HCM. Kết quả nghiên cứu cho thấy nồng độ trung bình của khí CO 2 , CH 4 , N 2 O và CO lần lượt là 425.24 ± 11.20 ppm, 2152.25 ± 515.02 ppb, 335.58 ± 10.36 ppb, 822,38±664,33 ppb. Nồng độ khí CH 4 đạt cực đại vào lúc sáng sớm. Nồng độ khí N 2 O đạt cực đại vào lúc nửa đêm. Trong khi đó, khí CO và CO 2 có nồng độ cao vào khoảng giờ cao điểm 6:00-7:00 giờ và 18:00-19:00 giờ. Từ diễn biến nồng độ các khí nhà kính cho thấy, khí CO và CO 2 có nguồn gốc từ hoạt động giao thông, khí N 2 O và khí CH 4 có thể từ các nguồn khác ngoài giao thông. Kết quả cũng cho thấy rằng hoạt động tại các quán bar sử dụng bóng cười là một trong những nguyên nhân làm gia tăng nồng độ N 2 O trong không khí ở TP.HCM. Từ khóa: Khí nhà kính, TP.HCM, methane, nitrous oxide, carbon dioxide, carbon monoxide. 1. GIỚI THIỆU Hiệu ứng nhà kính xảy ra tự nhiên trong bầu khí quyển, tuy nhiên hoạt động của con người đã làm tăng đáng kể lượng khí nhà kính. Báo cáo đánh giá thứ tư của Hội đồng Liên Chính phủ về Biến đổi khí hậu (Intergovernmental Panel on Climate Change-IPCC) năm 2007 chỉ ra rằng, nhiệt độ trung bình toàn cầu từ năm 1906 đến 2005 tăng 0.74 °C do sự tăng lên đáng kể nồng độ của các khí nhà kính trong khí quyển (Liu et al., 2019). Những thay đổi về nồng độ khí nhà kính góp phần làm thay đổi khí hậu toàn cầu và mang lại những ảnh hưởng tiêu cực cho sức khỏe con người và môi trường. Hậu quả môi trường của biến đổi khí hậu như sóng nhiệt, mực nước biển dâng cao, thay đổi lượng mưa dẫn đến lũ lụt và hạn hán, bão dữ dội và chất lượng không khí ảnh hưởng trực tiếp và gián tiếp đến sức khỏe, xã hội và tâm lý của con người đồng thời nông nghiệp, tài nguyên nước, rừng, động vật hoang dã và khu vực ven biển đều dễ bị tổn thương trước biến đổi khí hậu. Hiện tượng đại dương ấm lên, độ ẩm tăng và khí hậu thay đổi đang dẫn đến các kiểu thời tiết khắc nghiệt, làm gia tăng các bệnh truyền nhiễm, bệnh dại mới xuất hiện, cũng như ảnh hưởng sức khỏe do phát thải các chất ô nhiễm độc hại trong không khí đến các đối tượng dễ bị tổn thương như trẻ em, người già (Epstein et al., 2011). Các khí nhà kính chính bao gồm CO 2 , CH 4 , O 3 , N 2 O, CFCs, SF 6. Khí CO không phải phải là khí nhà kính trựcc tiếp mà là khí nhà kính gián tiếp thông quan phản ứng với gốc tự do trong khí quyển để hình thành khí CO 2 và O 3 (IPCC, 2018). Nghiên cứu này được thực hiện là một trong những nghiên cứu đầu tiên đo liên tục các khí nhà kính bao gồm CO 2 , N 2 O, CH 4 và CO ở TP.HCM, Việt Nam. 2. PHƯƠNG PHÁP NGHIÊN CỨU Nghiên cứu tiến hành quan trắc khí nhà kính tại Trạm quan trắc chất lượng không khí của Khoa Môi trường ở độ cao cách mặt đất 45 m, trên tầng thượng tòa nhà 11 tầng ở Trường Đại học Khoa học Tự nhiên, Đại học Quốc gia TP.HCM (tọa độ 10°45'45.56" N, 106°40'56.86" E). Nồng độ các khí
We present a characterization of the chemical composition of the atmosphere of the Brazilian Amaz... more We present a characterization of the chemical composition of the atmosphere of the Brazilian Amazon rainforest based on trace gases measurements carried out during the South American Biomass Burning Analysis (SAMBBA) airborne experiment in September 2012. We analyzed the observations of primary biomass burning emission tracers, i.e., carbon monoxide (CO) and nitrogen oxides (NOx), ozone (O3), isoprene, and its main oxidation products, methyl vinyl ketone (MVK), methacrolein (MACR), and hydroxyhydroperoxides (ISOPOOH). The focus of SAMBBA was primarily on biomass burning emissions, but there were also several flights in areas of the Amazon forest not directly affected by biomass burning, revealing a background with a signature of biomass burning in the chemical composition due to long-range transport of biomass burning tracers from both Africa and the eastern part of Amazonia. We used the [MVK+MACR+ ISOPOOH]/[Isoprene] ratio and the hydroxyl radical (OH) indirect calculation to assess the oxidative capacity of the Amazon forest atmosphere. We compared the background regions (CO<150 ppbv), fresh and aged smoke plumes classified according to their photochemical age ([O3]/[CO]), to evaluate the impact of biomass burning emissions in the oxidative capacity of the Amazon forest atmosphere. We observed that biomass burning emissions disturb the isoprene oxidation reactions, especially for fresh plumes ([MVK+MACR+ISOPOOH]/[isoprene] = 7). The oxidation of isoprene is higher in fresh smoke plumes at lower altitudes (~ 500 m) than in aged smoke plumes, anticipating near the surface a complex chain of oxidation reactions, which may be related to the secondary organic aerosols (SOA) formation. We proposed a refinement of the OH calculation based on the sequential reaction model, which considers vertical and horizontal transport for both biomass burning regimes and background environment. Our approach for the [OH] estimation resulted in values of the same order of magnitude of a recent observation in the Amazon rainforest [OH] ≅ 10 6 (molecules cm-3). During the fresh Atmos. Chem. Phys. Discuss.,
We present a method to derive atmosphericobservation-based estimates of carbon dioxide (CO 2) flu... more We present a method to derive atmosphericobservation-based estimates of carbon dioxide (CO 2) fluxes at the national scale, demonstrated using data from a network of surface tall-tower sites across the UK and Ireland over the period 2013-2014. The inversion is carried out using simulations from a Lagrangian chemical transport model and an innovative hierarchical Bayesian Markov chain Monte Carlo (MCMC) framework, which addresses some of the traditional problems faced by inverse modelling studies, such as subjectivity in the specification of model and prior uncertainties. Biospheric fluxes related to gross primary productivity and terrestrial ecosystem respiration are solved separately in the inversion and then combined a posteriori to determine net ecosystem exchange of CO 2. Two different models, Data Assimilation Linked Ecosystem Carbon (DALEC) and Joint UK Land Environment Simulator (JULES), provide prior estimates for these fluxes. We carry out separate inversions to assess the impact of these different priors on the posterior flux estimates and evaluate the differences between the prior and posterior estimates in terms of missing model components. The Numerical Atmospheric dispersion Modelling Environment (NAME) is used to relate fluxes to the measurements taken across the regional network. Posterior CO 2 estimates from the two inversions agree within estimated uncertainties, despite large differences in the prior fluxes from the different models. With our method, averaging results from 2013 and 2014, we find a total annual net biospheric flux for the UK of 8 ± 79 Tg CO 2 yr −1 (DALEC prior) and 64 ± 85 Tg CO 2 yr −1 (JULES prior), where negative values represent an uptake of CO 2. These biospheric CO 2 estimates show that annual UK biospheric sources and sinks are roughly in balance. These annual mean estimates consistently indicate a greater net release of CO 2 than the prior estimates, which show much more pronounced uptake in summer months.
Supplementary material from "<i>δ</i><sup>13</sup>C methane source signatures from tropical wetland and rice field emissions
The atmospheric methane (CH<sub>4</sub>) burden is rising sharply, but the causes are... more The atmospheric methane (CH<sub>4</sub>) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH<sub>4</sub> emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new <i>δ</i><sup>13</sup>C<sub>CH<sub>4</sub></sub> signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. In summary, tropical wetland <i>δ</i><sup>13</sup>C<sub>CH<sub>4</sub></sub> generally range between −62 and −52‰ and rice paddies between −59 and −57‰. Long-term monitoring of <i>δ</i><sup>13</sup>C<sub>CH<sub>4</sub></sub> in ambient air has been conducted at...
Supplementary Tables and Figures from <i>δ</i><sup>13</sup>C methane source signatures from tropical wetland and rice field emissions
Detailed site location information along with extra information on Botswana and Bolivian long-ter... more Detailed site location information along with extra information on Botswana and Bolivian long-term time series data
Determining UK regional isotopic source signatures of methane using long-term records
&amp;lt;p&amp;gt;Long term records are vital for understanding the way in which our envir... more &amp;lt;p&amp;gt;Long term records are vital for understanding the way in which our environment is changing. &amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;A significant rise in atmospheric methane began in 2007 and has accelerated thereafter, particularly since 2014. This trend was observed globally and was coupled with a sustained isotopic shift to values more depleted in &amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C (more negative &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;). Currently, there is no consensus as to why these observations have occurred. However, long term methane isotopic measurements can provide information about changes in the source mix of this important greenhouse gas. Here, long term records of both methane mole fraction and &amp;amp;#160;&amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; from 5 sites across the UK are presented, showing an increase in CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; and a decrease in &amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C from 2007, similar to those recorded globally, but at the regional-local scale. The approximately weekly in-situ measurements offer an insight into both suburban and background regions of the UK.&amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;A method for isotopic discrimination from longer term atmospheric measurements of CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and &amp;amp;#160;&amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; as outlined by Miller and Tans (2003) is utilised in this work. Miller-Tans analysis allows for the explicit specification of background values, vital when dealing with long term records due to both seasonal, local, regional and global background variations in atmospheric CH&amp;lt;sub&amp;gt;4 &amp;lt;/sub&amp;gt;and &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4.&amp;lt;/sub&amp;gt; &amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;When applying the Miller-Tans method to the long-term data from UK sites, as expected, the heaviest &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; source signatures, which are associated with industrial sources such as gas leaks, are observed for the suburban sites, and biogenic, lighter, sources for the background sites. The methane source distribution is compared to results from mobile measurements carried out at Royal Holloway, University of London and to the UK National Atmospheric Emissions Inventory (NAEI).&amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;From the initial results, it seems that there is a larger proportion of thermogenic/pyrogenic emissions in this data compared to the NAEI inventory. At all sites, there has been a post 2006 decline in &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C-CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;. Using the Miller Tans method, it is possible to calculate bulk regional source signatures which highlight a distinction between rural and suburban emissions, in general agreement with the NAEI.&amp;lt;/p&amp;gt;
We present a novel high-resolution inverse modelling system ("FLEXVAR") based on FLEXPART-COSMO b... more We present a novel high-resolution inverse modelling system ("FLEXVAR") based on FLEXPART-COSMO back trajectories driven by COSMO meteorological fields at 7 km × 7 km resolution over the European COSMO-7 domain and the four-dimensional variational (4DVAR) data assimilation technique. FLEXVAR is coupled offline with the global inverse modelling system TM5-4DVAR to provide background mole fractions ("baselines") consistent with the global observations assimilated in TM5-4DVAR. We have applied the FLEXVAR system for the inverse modelling of European emissions in 2018 using 24 stations with in situ measurements, complemented with data from five stations with discrete air sampling (and additional stations outside the European COSMO-7 domain used for the global TM5-4DVAR inversions). The sensitivity of the FLEXVAR inversions to different approaches to calculate the baselines, different parameterizations of the model representation error, different settings of the prior error covariance parameters, different prior inventories and
CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources... more CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources (emissions to the atmosphere) and sinks (removal from the atmosphere) of carbon dioxide around the world. CarbonTracker uses atmospheric CO2 observations from a host of collaborators and simulated atmospheric transport to estimate these surface fluxes of CO2. This release of CarbonTracker Near Real-Time, CT-NRT.v2021-3, provides global estimates of surface-atmosphere fluxes of CO2 from April 2018 through August 2020.
CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources... more CarbonTracker is a CO2 measurement and modeling system developed by NOAA to keep track of sources (emissions to the atmosphere) and sinks (removal from the atmosphere) of carbon dioxide around the world. CarbonTracker uses atmospheric CO2 observations from a host of collaborators and simulated atmospheric transport to estimate these surface fluxes of CO2. This release of CarbonTracker, CT2019B, provides global estimates of surface-atmosphere fluxes of CO2 from January 2000 through December 2018.
Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1957-2020; obspack_co2_1_GLOBALVIEWplus_v7.0_2021-08-18
This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 20... more This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 2014; www.earth-syst-sci-data.net/6/375/2014/]. The framework is designed to bring together atmospheric greenhouse gas (GHG) observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. ObsPack products are intended to support GHG budget studies and represent a new generation of cooperative value-added GHG data products. This product includes 524 atmospheric carbon dioxide datasets derived from observations made by 70 laboratories from 21 countries. Data for the period 1957-2020 (where available) are included.
Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1957-2019; obspack_co2_1_GLOBALVIEWplus_v6.0_2020-09-11
A full list of all creators for this product can be found at www.esrl.noaa.gov/gmd/ccgg/obspack/p... more A full list of all creators for this product can be found at www.esrl.noaa.gov/gmd/ccgg/obspack/providerlist/obspack_co2_1_GLOBALVIEWplus_v6.0_2020-09-11.html. This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 2014; www.earth-syst-sci-data.net/6/375/2014/]. The framework is designed to bring together atmospheric greenhouse gas (GHG) observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. ObsPack products are intended to support GHG budget studies and represent a new generation of cooperative value-added GHG data products. This product includes 471 atmospheric carbon dioxide datasets derived from observations made by 54 laboratories from 21 countries. Data for the period 1957-2019 (where available) are included.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2021
The atmospheric methane (CH 4 ) burden is rising sharply, but the causes are still not well under... more The atmospheric methane (CH 4 ) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH 4 emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new δ 13 C CH 4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring of δ 13 C CH 4 in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH 4 sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH 4 to the atmosphere during periods of reduced wetland exte...
Volatile organic compounds (VOCs) and oxygenated VOCs (OVOCs) were measured in Ho Chi Minh City (... more Volatile organic compounds (VOCs) and oxygenated VOCs (OVOCs) were measured in Ho Chi Minh City (HCMC) and Hanoi, the two largest and most populous cities in Vietnam. The purpose of this study is to better understand the VOC atmospheric composition and their role in ground-level ozone formation. Online measurements of a wide range of VOCs and other pollutants were conducted using numerous instruments during different seasons (dry and rainy) in HCMC and Hanoi (spring). Our results show that the mean mixing ratio of total measured VOCs in Hanoi was 80.8 ± 40.7 ppb (mean ± standard deviation), and was similar to that observed during the rainy season (75.2 ± 44.8 ppb) in HCMC. During the dry season campaign in HCMC, which was coincident with the Hanoi campaign, total VOC was around 50% lower (40.7 ± 19.5 ppb), largely a result of increased planetary boundary layer (PBL) height and the direction of the prevailing wind. VOC profiles in both cities were dominated by alkanes (31-35%) and OVOCs (27-33%) and the proportion of alkenes (13-17%) and aromatics (12-19%) were comparable. Similarities in diurnal variation for most VOC species (except for isoprene) are seen in both cities with two clear peaks during the morning (7:00-8:00 am) and evening (18:00 pm) rush hours, as observed for vehicular-combustion tracers (acetylene and CO). Comparisons of the ambient ratios of paired VOCs, namely i/n-pentane, and toluene/benzene, with those reported in motorcycle exhaust, roadside and gasoline samples indicate that motorcycle-related emission is likely a major contributor to VOC pollution. According to the propylene-equivalent concentration (PE conc.) and maximum incremental reactivity (MIR) methods, alkenes and aromatics were determined to be the main contributors to reactivity and ozone potential formation. Furthermore, the initial mixing ratio of VOC species was estimated based on the photochemical age method. The consumed VOCs (initial VOCs minus measured VOCs) has a similar variation trend to ground-level ozone, and a good correlation is observed in HCMC. In contrast, this result was not seen in Hanoi despite relatively high levels of PE conc. and MIR.
Philosophical Transactions of the Royal Society B: Biological Sciences, 2020
During the summer of 2018, a widespread drought developed over Northern and Central Europe. The i... more During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO 2 ) exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO 2 seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO 2 gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO 2 cycles from 48 European stations were available for 2017 and 2018. Earlie...
Sarah Moller (4) , James Lee (4) , Stephane Bauguitte (5) , Stewart Vaughan (6) , Will Morgan (7)... more Sarah Moller (4) , James Lee (4) , Stephane Bauguitte (5) , Stewart Vaughan (6) , Will Morgan (7) , Bin Ouyang (8) , Oliver Kennedy (8) , Rod Jones (8) , Grant Forster (9) , Claire Reeves (9)
Atmospheric Chemistry and Physics Discussions, 2014
Wet deposition is the dominant mechanism for removing black carbon (BC) from the atmosphere, and ... more Wet deposition is the dominant mechanism for removing black carbon (BC) from the atmosphere, and is key in determining its atmospheric lifetime, vertical gradient and global transport. Despite the importance of BC in the climate system, especially in terms of its ability to modulate the radiative energy budget, there are few quantitative case studies of wet removal in ambient environments. We present a case study of BC wet removal by examining aerosol size distributions and BC coating properties sampled in three Canadian boreal biomass burning plumes, one of which passed through a precipitating cloud. In this plume, the largest and most coated BC particles were found to be preferentially removed, suggesting that nucleation scavenging was the likely dominant mechanism. Calculated mass absorption coefficient (MAC) in the plumes showed no significant variation, as the shifts to smaller BC cores and thinner coatings had opposing effects. Similarly, calculated single-scatter albedo (SSA)...
Atmospheric peroxy nitrates (PNs or RO2NO2), alkyl nitrates (ANs or RONO2) and nitric acid (HNO 3... more Atmospheric peroxy nitrates (PNs or RO2NO2), alkyl nitrates (ANs or RONO2) and nitric acid (HNO 3) are high oxides of nitrogen formed as intermediate or final products in the oxidation chains of volatile organic compounds (VOC) that, in the presence of nitrogen oxides (NO x = NO + NO 2), may produce ozone (O 3). The main branch of the reaction between RO 2 and NO produce NO 2 , which upon photolysis generates O 3 , while a minor branch makes ANs; therefore the alkyl nitrate concentrations are generally considered as a Published by Copernicus Publications on behalf of the European Geosciences Union.
We describe the design and execution of the BOR-TAS (Quantifying the impact of BOReal forest fire... more We describe the design and execution of the BOR-TAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) experiment, which has the overarching objective of understanding the chemical aging of air masses that contain the emission products from seasonal boreal wildfires and how these air masses subsequently impact downwind atmospheric composition. The central focus of the experiment was a twoweek deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA) over eastern Canada, based out of Published by Copernicus Publications on behalf of the European Geosciences Union.
Nghiên cứu thực hiện quan trắc liên tục các khí nhà kính carbon dioxide (CO 2), nitrous oxide (N ... more Nghiên cứu thực hiện quan trắc liên tục các khí nhà kính carbon dioxide (CO 2), nitrous oxide (N 2 O), methane (CH 4) và carbon monoxide (CO) từ tháng 10 năm 2018 đến tháng 4 năm 2019 ở Thành phố Hồ Chí Minh (TP.HCM). Các khí nhà kính được đo bằng thiết bị Los Gatos Research với độ phân giải cao. Nghiên cứu này là một trong những nghiên cứu đầu tiên đo đạc các khí nhà kính với độ phân giải thời gian cao ở TP.HCM. Kết quả nghiên cứu cho thấy nồng độ trung bình của khí CO 2 , CH 4 , N 2 O và CO lần lượt là 425.24 ± 11.20 ppm, 2152.25 ± 515.02 ppb, 335.58 ± 10.36 ppb, 822,38±664,33 ppb. Nồng độ khí CH 4 đạt cực đại vào lúc sáng sớm. Nồng độ khí N 2 O đạt cực đại vào lúc nửa đêm. Trong khi đó, khí CO và CO 2 có nồng độ cao vào khoảng giờ cao điểm 6:00-7:00 giờ và 18:00-19:00 giờ. Từ diễn biến nồng độ các khí nhà kính cho thấy, khí CO và CO 2 có nguồn gốc từ hoạt động giao thông, khí N 2 O và khí CH 4 có thể từ các nguồn khác ngoài giao thông. Kết quả cũng cho thấy rằng hoạt động tại các quán bar sử dụng bóng cười là một trong những nguyên nhân làm gia tăng nồng độ N 2 O trong không khí ở TP.HCM. Từ khóa: Khí nhà kính, TP.HCM, methane, nitrous oxide, carbon dioxide, carbon monoxide. 1. GIỚI THIỆU Hiệu ứng nhà kính xảy ra tự nhiên trong bầu khí quyển, tuy nhiên hoạt động của con người đã làm tăng đáng kể lượng khí nhà kính. Báo cáo đánh giá thứ tư của Hội đồng Liên Chính phủ về Biến đổi khí hậu (Intergovernmental Panel on Climate Change-IPCC) năm 2007 chỉ ra rằng, nhiệt độ trung bình toàn cầu từ năm 1906 đến 2005 tăng 0.74 °C do sự tăng lên đáng kể nồng độ của các khí nhà kính trong khí quyển (Liu et al., 2019). Những thay đổi về nồng độ khí nhà kính góp phần làm thay đổi khí hậu toàn cầu và mang lại những ảnh hưởng tiêu cực cho sức khỏe con người và môi trường. Hậu quả môi trường của biến đổi khí hậu như sóng nhiệt, mực nước biển dâng cao, thay đổi lượng mưa dẫn đến lũ lụt và hạn hán, bão dữ dội và chất lượng không khí ảnh hưởng trực tiếp và gián tiếp đến sức khỏe, xã hội và tâm lý của con người đồng thời nông nghiệp, tài nguyên nước, rừng, động vật hoang dã và khu vực ven biển đều dễ bị tổn thương trước biến đổi khí hậu. Hiện tượng đại dương ấm lên, độ ẩm tăng và khí hậu thay đổi đang dẫn đến các kiểu thời tiết khắc nghiệt, làm gia tăng các bệnh truyền nhiễm, bệnh dại mới xuất hiện, cũng như ảnh hưởng sức khỏe do phát thải các chất ô nhiễm độc hại trong không khí đến các đối tượng dễ bị tổn thương như trẻ em, người già (Epstein et al., 2011). Các khí nhà kính chính bao gồm CO 2 , CH 4 , O 3 , N 2 O, CFCs, SF 6. Khí CO không phải phải là khí nhà kính trựcc tiếp mà là khí nhà kính gián tiếp thông quan phản ứng với gốc tự do trong khí quyển để hình thành khí CO 2 và O 3 (IPCC, 2018). Nghiên cứu này được thực hiện là một trong những nghiên cứu đầu tiên đo liên tục các khí nhà kính bao gồm CO 2 , N 2 O, CH 4 và CO ở TP.HCM, Việt Nam. 2. PHƯƠNG PHÁP NGHIÊN CỨU Nghiên cứu tiến hành quan trắc khí nhà kính tại Trạm quan trắc chất lượng không khí của Khoa Môi trường ở độ cao cách mặt đất 45 m, trên tầng thượng tòa nhà 11 tầng ở Trường Đại học Khoa học Tự nhiên, Đại học Quốc gia TP.HCM (tọa độ 10°45'45.56" N, 106°40'56.86" E). Nồng độ các khí
We present a characterization of the chemical composition of the atmosphere of the Brazilian Amaz... more We present a characterization of the chemical composition of the atmosphere of the Brazilian Amazon rainforest based on trace gases measurements carried out during the South American Biomass Burning Analysis (SAMBBA) airborne experiment in September 2012. We analyzed the observations of primary biomass burning emission tracers, i.e., carbon monoxide (CO) and nitrogen oxides (NOx), ozone (O3), isoprene, and its main oxidation products, methyl vinyl ketone (MVK), methacrolein (MACR), and hydroxyhydroperoxides (ISOPOOH). The focus of SAMBBA was primarily on biomass burning emissions, but there were also several flights in areas of the Amazon forest not directly affected by biomass burning, revealing a background with a signature of biomass burning in the chemical composition due to long-range transport of biomass burning tracers from both Africa and the eastern part of Amazonia. We used the [MVK+MACR+ ISOPOOH]/[Isoprene] ratio and the hydroxyl radical (OH) indirect calculation to assess the oxidative capacity of the Amazon forest atmosphere. We compared the background regions (CO<150 ppbv), fresh and aged smoke plumes classified according to their photochemical age ([O3]/[CO]), to evaluate the impact of biomass burning emissions in the oxidative capacity of the Amazon forest atmosphere. We observed that biomass burning emissions disturb the isoprene oxidation reactions, especially for fresh plumes ([MVK+MACR+ISOPOOH]/[isoprene] = 7). The oxidation of isoprene is higher in fresh smoke plumes at lower altitudes (~ 500 m) than in aged smoke plumes, anticipating near the surface a complex chain of oxidation reactions, which may be related to the secondary organic aerosols (SOA) formation. We proposed a refinement of the OH calculation based on the sequential reaction model, which considers vertical and horizontal transport for both biomass burning regimes and background environment. Our approach for the [OH] estimation resulted in values of the same order of magnitude of a recent observation in the Amazon rainforest [OH] ≅ 10 6 (molecules cm-3). During the fresh Atmos. Chem. Phys. Discuss.,
We present a method to derive atmosphericobservation-based estimates of carbon dioxide (CO 2) flu... more We present a method to derive atmosphericobservation-based estimates of carbon dioxide (CO 2) fluxes at the national scale, demonstrated using data from a network of surface tall-tower sites across the UK and Ireland over the period 2013-2014. The inversion is carried out using simulations from a Lagrangian chemical transport model and an innovative hierarchical Bayesian Markov chain Monte Carlo (MCMC) framework, which addresses some of the traditional problems faced by inverse modelling studies, such as subjectivity in the specification of model and prior uncertainties. Biospheric fluxes related to gross primary productivity and terrestrial ecosystem respiration are solved separately in the inversion and then combined a posteriori to determine net ecosystem exchange of CO 2. Two different models, Data Assimilation Linked Ecosystem Carbon (DALEC) and Joint UK Land Environment Simulator (JULES), provide prior estimates for these fluxes. We carry out separate inversions to assess the impact of these different priors on the posterior flux estimates and evaluate the differences between the prior and posterior estimates in terms of missing model components. The Numerical Atmospheric dispersion Modelling Environment (NAME) is used to relate fluxes to the measurements taken across the regional network. Posterior CO 2 estimates from the two inversions agree within estimated uncertainties, despite large differences in the prior fluxes from the different models. With our method, averaging results from 2013 and 2014, we find a total annual net biospheric flux for the UK of 8 ± 79 Tg CO 2 yr −1 (DALEC prior) and 64 ± 85 Tg CO 2 yr −1 (JULES prior), where negative values represent an uptake of CO 2. These biospheric CO 2 estimates show that annual UK biospheric sources and sinks are roughly in balance. These annual mean estimates consistently indicate a greater net release of CO 2 than the prior estimates, which show much more pronounced uptake in summer months.
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Papers by Grant Forster