1
|
Wang J, Wu B, Zheng X, Ma J, Yu W, Chen B, Chu C. Insights into the Crystallinity-Dependent Photochemical Productions of Reactive Oxygen Species from Iron Minerals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10623-10631. [PMID: 38781516 DOI: 10.1021/acs.est.4c01843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Iron minerals are widespread in earth's surface water and soil. Recent studies have revealed that under sunlight irradiation, iron minerals are photoactive on producing reactive oxygen species (ROS), a group of key species in regulating elemental cycling, microbe inactivation, and pollutant degradation. In nature, iron minerals exhibit varying crystallinity under different hydrogeological conditions. While crystallinity is a known key parameter determining the overall activity of iron minerals, the impact of iron mineral crystallinity on photochemical ROS production remains unknown. Here, we assessed the photochemical ROS production from ferrihydrites with different degrees of crystallinity. All examined ferrihydrites demonstrated photoactivity under irradiation, resulting in the generation of hydrogen peroxide (H2O2) and hydroxyl radical (•OH). The photochemical ROS production from ferrihydrites increased with decreasing ferrihydrite crystallinity. The crystallinity-dependent photochemical •OH production was primarily attributed to conduction band reduction reactions, with the reduction of O2 by conduction band electrons being the rate-limiting key process. Conversely, the crystallinity of iron minerals had a negligible influence on photon-to-electron conversion efficiency or surface Fenton-like activity. The difference in ROS productions led to a discrepant degradation efficiency of organic pollutants on iron mineral surfaces. Our study provides valuable insights into the crystallinity-dependent ROS productions from iron minerals in natural systems, emphasizing the significance of iron mineral photochemistry in natural sites with abundant lower-crystallinity iron minerals such as wetland water and surface soils.
Collapse
Affiliation(s)
- Jingyi Wang
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Binbin Wu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Xiaoshan Zheng
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Junye Ma
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Wanchao Yu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Chiheng Chu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| |
Collapse
|
2
|
Patel A, Mallik C, Chandra N, Patra PK, Steinbacher M. Revisiting regional and seasonal variations in decadal carbon monoxide variability: Global reversal of growth rate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 909:168476. [PMID: 37984655 DOI: 10.1016/j.scitotenv.2023.168476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/09/2023] [Accepted: 11/08/2023] [Indexed: 11/22/2023]
Abstract
Carbon monoxide (CO) is one of the important trace gases in the atmosphere capturing the evolution of chemical properties of the troposphere. Here we analyze the growth rates of CO during the period of 1991-2020 using in situ measurements from the World Meteorological Organization's (WMO) Global Atmospheric Watch (GAW) program. The analysis of trends has been done on different spatial and temporal scales. Our analysis supports the decline in the overall CO mixing ratios over the globe but inter-decadal and regional trend analysis has shown heterogeneous changes in the given period of study. On average, there has been a decrease of -16.22 ± 1.92 ppb and -4.5 ± 0.64 ppb observed at the sites in the northern hemisphere (NH) and southern hemisphere (SH), respectively. This decline occurred at rates of -0.80 ± 0.12 ppb yr-1 in the NH and - 0.12 ± 0.03 ppb yr-1 in the SH. Bifurcating the annual trends for seasonal analysis reveals the impact of emissions, chemistry and atmospheric transport on CO variation over different regional clusters of stations. Seasonal trend analysis provides further evidence regarding heterogeneous patterns in the South-East Asia region. Our study highlights a slowdown in CO decline during the 2011-2020 decade when compared to the rate of decrease observed in 2001-2010. This is inferred from the variability and much slower decline of CO emissions across different regions, contributing to a weakening in CO trends.
Collapse
Affiliation(s)
- Ankit Patel
- Department of Atmospheric Science, Central University of Rajasthan, Ajmer 305801, India
| | - Chinmay Mallik
- Department of Atmospheric Science, Central University of Rajasthan, Ajmer 305801, India.
| | - Naveen Chandra
- Research Institute for Global Change, JAMSTEC, Yokohama 2360001, Japan
| | - Prabir K Patra
- Research Institute for Global Change, JAMSTEC, Yokohama 2360001, Japan; Research Institute for Humanity and Nature, Kyoto, Japan
| | - Martin Steinbacher
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland
| |
Collapse
|
3
|
Stavert AR, Saunois M, Canadell JG, Poulter B, Jackson RB, Regnier P, Lauerwald R, Raymond PA, Allen GH, Patra PK, Bergamaschi P, Bousquet P, Chandra N, Ciais P, Gustafson A, Ishizawa M, Ito A, Kleinen T, Maksyutov S, McNorton J, Melton JR, Müller J, Niwa Y, Peng S, Riley WJ, Segers A, Tian H, Tsuruta A, Yin Y, Zhang Z, Zheng B, Zhuang Q. Regional trends and drivers of the global methane budget. GLOBAL CHANGE BIOLOGY 2022; 28:182-200. [PMID: 34553464 PMCID: PMC9298116 DOI: 10.1111/gcb.15901] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/02/2021] [Accepted: 09/12/2021] [Indexed: 05/28/2023]
Abstract
The ongoing development of the Global Carbon Project (GCP) global methane (CH4 ) budget shows a continuation of increasing CH4 emissions and CH4 accumulation in the atmosphere during 2000-2017. Here, we decompose the global budget into 19 regions (18 land and 1 oceanic) and five key source sectors to spatially attribute the observed global trends. A comparison of top-down (TD) (atmospheric and transport model-based) and bottom-up (BU) (inventory- and process model-based) CH4 emission estimates demonstrates robust temporal trends with CH4 emissions increasing in 16 of the 19 regions. Five regions-China, Southeast Asia, USA, South Asia, and Brazil-account for >40% of the global total emissions (their anthropogenic and natural sources together totaling >270 Tg CH4 yr-1 in 2008-2017). Two of these regions, China and South Asia, emit predominantly anthropogenic emissions (>75%) and together emit more than 25% of global anthropogenic emissions. China and the Middle East show the largest increases in total emission rates over the 2000 to 2017 period with regional emissions increasing by >20%. In contrast, Europe and Korea and Japan show a steady decline in CH4 emission rates, with total emissions decreasing by ~10% between 2000 and 2017. Coal mining, waste (predominantly solid waste disposal) and livestock (especially enteric fermentation) are dominant drivers of observed emissions increases while declines appear driven by a combination of waste and fossil emission reductions. As such, together these sectors present the greatest risks of further increasing the atmospheric CH4 burden and the greatest opportunities for greenhouse gas abatement.
Collapse
Affiliation(s)
- Ann R. Stavert
- Global Carbon ProjectCSIRO Oceans and AtmosphereAspendaleVictoriaAustralia
- Global Carbon ProjectCSIRO Oceans and AtmosphereCanberraACTAustralia
| | - Marielle Saunois
- Laboratoire des Sciences du Climat et de l’Environnement, LSCE‐IPSL (CEA‐CNRS‐UVSQ)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Josep G. Canadell
- Global Carbon ProjectCSIRO Oceans and AtmosphereAspendaleVictoriaAustralia
- Global Carbon ProjectCSIRO Oceans and AtmosphereCanberraACTAustralia
| | - Benjamin Poulter
- NASA Goddard Space Flight CenterBiospheric Science LaboratoryGreenbeltMarylandUSA
| | - Robert B. Jackson
- Department of Earth System ScienceWoods Institute for the Environment, and Precourt Institute for EnergyStanford UniversityStanfordCaliforniaUSA
| | - Pierre Regnier
- Department of Geoscience, Environment and Society ‐ BGEOSYSUniversité Libre de BruxellesBrusselsBelgium
| | - Ronny Lauerwald
- Laboratoire des Sciences du Climat et de l’Environnement, LSCE‐IPSL (CEA‐CNRS‐UVSQ)Université Paris‐SaclayGif‐sur‐YvetteFrance
- Department of Geoscience, Environment and Society ‐ BGEOSYSUniversité Libre de BruxellesBrusselsBelgium
- Université Paris‐SaclayINRAEAgroParisTechUMR ECOSYSThiverval‐GrignonFrance
| | - Peter A. Raymond
- Yale School of the EnvironmentYale UniversityNew HavenConnecticutUSA
| | - George H. Allen
- Department of GeographyTexas A&M UniversityCollege StationTexasUSA
| | - Prabir K. Patra
- Research Institute for Global ChangeJAMSTECYokohamaJapan
- Center for Environmental Remote SensingChiba UniversityChibaJapan
| | | | - Phillipe Bousquet
- Laboratoire des Sciences du Climat et de l’Environnement, LSCE‐IPSL (CEA‐CNRS‐UVSQ)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Naveen Chandra
- Center for Global Environmental ResearchNational Institute for Environmental Studies (NIES)TsukubaJapan
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l’Environnement, LSCE‐IPSL (CEA‐CNRS‐UVSQ)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Adrian Gustafson
- Department of Physical Geography and Ecosystem ScienceLund UniversityLundSweden
- Centre for Environmental and Climate ScienceLund UniversityLundSweden
| | - Misa Ishizawa
- Center for Global Environmental ResearchNational Institute for Environmental Studies (NIES)TsukubaJapan
| | - Akihiko Ito
- Center for Global Environmental ResearchNational Institute for Environmental Studies (NIES)TsukubaJapan
| | | | - Shamil Maksyutov
- Center for Global Environmental ResearchNational Institute for Environmental Studies (NIES)TsukubaJapan
| | - Joe McNorton
- Research DepartmentEuropean Centre for Medium‐Range Weather ForecastsReadingUK
| | - Joe R. Melton
- Climate Research DivisionEnvironment and Climate Change CanadaVictoriaBritish ColumbiaCanada
| | - Jurek Müller
- Climate and Environmental PhysicsPhysics Institute and Oeschger Centre for Climate Change ResearchUniversity of BernBernSwitzerland
| | - Yosuke Niwa
- Center for Global Environmental ResearchNational Institute for Environmental Studies (NIES)TsukubaJapan
| | - Shushi Peng
- Laboratoire des Sciences du Climat et de l’Environnement, LSCE‐IPSL (CEA‐CNRS‐UVSQ)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - William J. Riley
- Climate and Ecosystem Sciences DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Arjo Segers
- Netherlands Organisation for Applied Scientific Research (TNO)UtrechtThe Netherlands
| | - Hanqin Tian
- International Center for Climate and Global Change ResearchSchool of Forestry and Wildlife SciencesAuburn UniversityAuburnAlabamaUSA
| | - Aki Tsuruta
- Finnish Meteorological InstituteHelsinkiFinland
| | - Yi Yin
- Division of Geophysical and Planetary ScienceCalifornia Institute of TechnologyPasadenaCaliforniaUSA
| | - Zhen Zhang
- Department of Geographical SciencesUniversity of MarylandCollege ParkMarylandUSA
| | - Bo Zheng
- Laboratoire des Sciences du Climat et de l’Environnement, LSCE‐IPSL (CEA‐CNRS‐UVSQ)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Qianlai Zhuang
- Department of Earth, Atmospheric, and Planetary SciencesPurdue UniversityWest LafayetteIndianaUSA
| |
Collapse
|
4
|
Lan X, Basu S, Schwietzke S, Bruhwiler LMP, Dlugokencky EJ, Michel SE, Sherwood OA, Tans PP, Thoning K, Etiope G, Zhuang Q, Liu L, Oh Y, Miller JB, Pétron G, Vaughn BH, Crippa M. Improved Constraints on Global Methane Emissions and Sinks Using δ 13C-CH 4. GLOBAL BIOGEOCHEMICAL CYCLES 2021; 35:e2021GB007000. [PMID: 34219915 PMCID: PMC8244052 DOI: 10.1029/2021gb007000] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/14/2021] [Accepted: 05/03/2021] [Indexed: 06/13/2023]
Abstract
We study the drivers behind the global atmospheric methane (CH4) increase observed after 2006. Candidate emission and sink scenarios are constructed based on proposed hypotheses in the literature. These scenarios are simulated in the TM5 tracer transport model for 1984-2016 to produce three-dimensional fields of CH4 and δ 13C-CH4, which are compared with observations to test the competing hypotheses in the literature in one common model framework. We find that the fossil fuel (FF) CH4 emission trend from the Emissions Database for Global Atmospheric Research 4.3.2 inventory does not agree with observed δ 13C-CH4. Increased FF CH4 emissions are unlikely to be the dominant driver for the post-2006 global CH4 increase despite the possibility for a small FF emission increase. We also find that a significant decrease in the abundance of hydroxyl radicals (OH) cannot explain the post-2006 global CH4 increase since it does not track the observed decrease in global mean δ 13C-CH4. Different CH4 sinks have different fractionation factors for δ 13C-CH4, thus we can investigate the uncertainty introduced by the reaction of CH4 with tropospheric chlorine (Cl), a CH4 sink whose abundance, spatial distribution, and temporal changes remain uncertain. Our results show that including or excluding tropospheric Cl as a 13 Tg/year CH4 sink in our model changes the magnitude of estimated fossil emissions by ∼20%. We also found that by using different wetland emissions based on a static versus a dynamic wetland area map, the partitioning between FF and microbial sources differs by 20 Tg/year, ∼12% of estimated fossil emissions.
Collapse
Affiliation(s)
- X. Lan
- Cooperative Institute for Research in Environmental SciencesUniversity of Colorado BoulderBoulderCOUSA
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - S. Basu
- Earth System Science Interdisciplinary CenterUniversity of MarylandCollege ParkMDUSA
- Global Modeling and Assimilation OfficeNational Aeronautics and Space Administration Goddard Space Flight CenterGreenbeltMDUSA
| | - S. Schwietzke
- Cooperative Institute for Research in Environmental SciencesUniversity of Colorado BoulderBoulderCOUSA
- Environmental Defense FundBerlinGermany
| | - L. M. P. Bruhwiler
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - E. J. Dlugokencky
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - S. E. Michel
- Institute of Arctic and Alpine ResearchUniversity of Colorado BoulderBoulderCOUSA
| | - O. A. Sherwood
- Institute of Arctic and Alpine ResearchUniversity of Colorado BoulderBoulderCOUSA
- Department of Earth and Environmental SciencesDalhousie UniversityHalifaxNova ScotiaCanada
| | - P. P. Tans
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - K. Thoning
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - G. Etiope
- Istituto Nazionale di Geofisica e VulcanologiaRomeItaly
- Faculty of Environmental Science and EngineeringBabes Bolyai UniversityCluj-NapocaRomania
| | - Q. Zhuang
- Department of Earth, Atmospheric, and Planetary SciencesPurdue UniversityWest LafayetteINUSA
| | - L. Liu
- Department of Earth, Atmospheric, and Planetary SciencesPurdue UniversityWest LafayetteINUSA
| | - Y. Oh
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
- Department of Earth, Atmospheric, and Planetary SciencesPurdue UniversityWest LafayetteINUSA
| | - J. B. Miller
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - G. Pétron
- Cooperative Institute for Research in Environmental SciencesUniversity of Colorado BoulderBoulderCOUSA
- Global Monitoring LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - B. H. Vaughn
- Institute of Arctic and Alpine ResearchUniversity of Colorado BoulderBoulderCOUSA
| | - M. Crippa
- Joint Research CentreEuropean CommissionIspraItaly
| |
Collapse
|
5
|
O3 Concentration and Its Relation with BVOC Emissions in a Subtropical Plantation. ATMOSPHERE 2021. [DOI: 10.3390/atmos12060711] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
An empirical model of O3 is developed using the measurements of emissions of biogenic volatile organic compounds (BVOCs), O3 concentration, global solar radiation, photosynthetically active radiation (PAR) and meteorological variables in a subtropical Pinus plantation, China, during 2013–2016. In view of the different structures of isoprene and monoterpenes, two empirical models of O3 concentration are developed, considering PAR absorption and scattering due to gases, liquids and particles (GLPs), as well as PAR attenuation caused by O3 and BVOCs. The estimated O3 is in agreement with the observations, and validation of the O3 empirical model is conducted. O3 concentrations are more sensitive to changes in PAR and water vapor than S/Q (horizontal diffuse to global solar radiation) and BVOC emissions. O3 is positive to changes in isoprene emission at low light and high GLPs, or negative at high light and low GLPs; O3 is negative to changes in monoterpene emissions. O3 are positive with the changes of PAR, water vapor and S/Q. It is suggested to control human-induced high BVOC emissions, regulate plant cutting, and reduce NOx and SO2 emissions more strictly than ever before. There are inverted U-shape interactions between O3 and its driving factors, and S/Q controls their turning points.
Collapse
|
6
|
GOSAT CH4 Vertical Profiles over the Indian Subcontinent: Effect of a Priori and Averaging Kernels for Climate Applications. REMOTE SENSING 2021. [DOI: 10.3390/rs13091677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We examined methane (CH4) variability over different regions of India and the surrounding oceans derived from thermal infrared (TIR) band observations (TIR CH4) by the Thermal and Near-infrared Sensor for carbon Observation—Fourier Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observation SATellite (GOSAT) for the period 2009–2014. This study attempts to understand the sensitivity of the vertical profile retrievals at different layers of the troposphere and lower stratosphere, on the basis of the averaging kernel (AK) functions and a priori assumptions, as applied to the simulated concentrations by the MIROC4.0-based Atmospheric Chemistry-Transport Model (MIROC4-ACTM). We stress that this is of particular importance when the satellite-derived products are analyzed using different ACTMs other than those used as retrieved a priori. A comparison of modeled and retrieved CH4 vertical profiles shows that the GOSAT/TANSO-FTS TIR instrument has sufficient sensitivity to provide critical information about the transport of CH4 from the top of the boundary layer to the upper troposphere. The mean mismatch between TIR CH4 and model is within 50 ppb, except for the altitude range above 150 hPa, where the sensitivity of TIR CH4 observations becomes very low. Convolved model profiles with TIR CH4 AK reduces the mismatch to less than the retrieval uncertainty. Distinct seasonal variations of CH4 have been observed near the atmospheric boundary layer (800 hPa), free troposphere (500 hPa), and upper troposphere (300 hPa) over the northern and southern regions of India, corresponding to the southwest monsoon (July–September) and post-monsoon (October–December) seasons. Analysis of the transport and emission contributions to CH4 suggests that the CH4 seasonal cycle over the Indian subcontinent is governed by both the heterogeneous distributions of surface emissions and the influence of the global monsoon divergent wind circulations. The major contrast between monsoon, and pre- and post-monsoon profiles of CH4 over Indian regions are noticed near the boundary layer heights, which is mainly caused by seasonal change in local emission strength with a peak during summer due to increased emissions from the paddy fields and wetlands. A strong difference between seasons in the middle and upper troposphere is caused by convective transport of the emission signals from the surface and redistribution in the monsoon anticyclone of upper troposphere. TIR CH4 observations provide additional information on CH4 in the region compared to what is known from in situ data and total-column (XCH4) measurements. Based on two emission sensitivity simulations compared to TIR CH4 observations, we suggest that the emissions of CH4 from the India region were 51.2 ± 4.6 Tg year−1 during the period 2009–2014. Our results suggest that improvements in the a priori profile shape in the upper troposphere and lower stratosphere (UT/LS) region would help better interpretation of CH4 cycling in the earth’s environment.
Collapse
|
7
|
Keller CA, Knowland KE, Duncan BN, Liu J, Anderson DC, Das S, Lucchesi RA, Lundgren EW, Nicely JM, Nielsen E, Ott LE, Saunders E, Strode SA, Wales PA, Jacob DJ, Pawson S. Description of the NASA GEOS Composition Forecast Modeling System GEOS-CF v1.0. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2021; 13:e2020MS002413. [PMID: 34221240 PMCID: PMC8244029 DOI: 10.1029/2020ms002413] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/18/2021] [Accepted: 03/16/2021] [Indexed: 05/11/2023]
Abstract
The Goddard Earth Observing System composition forecast (GEOS-CF) system is a high-resolution (0.25°) global constituent prediction system from NASA's Global Modeling and Assimilation Office (GMAO). GEOS-CF offers a new tool for atmospheric chemistry research, with the goal to supplement NASA's broad range of space-based and in-situ observations. GEOS-CF expands on the GEOS weather and aerosol modeling system by introducing the GEOS-Chem chemistry module to provide hindcasts and 5-days forecasts of atmospheric constituents including ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and fine particulate matter (PM2.5). The chemistry module integrated in GEOS-CF is identical to the offline GEOS-Chem model and readily benefits from the innovations provided by the GEOS-Chem community. Evaluation of GEOS-CF against satellite, ozonesonde and surface observations for years 2018-2019 show realistic simulated concentrations of O3, NO2, and CO, with normalized mean biases of -0.1 to 0.3, normalized root mean square errors between 0.1-0.4, and correlations between 0.3-0.8. Comparisons against surface observations highlight the successful representation of air pollutants in many regions of the world and during all seasons, yet also highlight current limitations, such as a global high bias in SO2 and an overprediction of summertime O3 over the Southeast United States. GEOS-CF v1.0 generally overestimates aerosols by 20%-50% due to known issues in GEOS-Chem v12.0.1 that have been addressed in later versions. The 5-days forecasts have skill scores comparable to the 1-day hindcast. Model skills can be improved significantly by applying a bias-correction to the surface model output using a machine-learning approach.
Collapse
Affiliation(s)
- Christoph A. Keller
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | - K. Emma Knowland
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | | | - Junhua Liu
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | - Daniel C. Anderson
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | - Sampa Das
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | - Robert A. Lucchesi
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Science Systems and Applications, Inc.LanhamMDUSA
| | | | - Julie M. Nicely
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Earth System Science Interdisciplinary CenterUniversity of MarylandCollege ParkLanhamMDUSA
| | - Eric Nielsen
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Science Systems and Applications, Inc.LanhamMDUSA
| | | | - Emily Saunders
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Science Systems and Applications, Inc.LanhamMDUSA
| | - Sarah A. Strode
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | - Pamela A. Wales
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Universities Space Research AssociationColumbiaMDUSA
| | - Daniel J. Jacob
- School of Engineering and Applied SciencesHarvard UniversityCambridgeMAUSA
| | | |
Collapse
|
8
|
Heimann I, Griffiths PT, Warwick NJ, Abraham NL, Archibald AT, Pyle JA. Methane Emissions in a Chemistry-Climate Model: Feedbacks and Climate Response. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2020; 12:e2019MS002019. [PMID: 33282114 PMCID: PMC7685116 DOI: 10.1029/2019ms002019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 06/12/2023]
Abstract
Understanding the past, present, and future evolution of methane remains a grand challenge. Here we have used a hierarchy of models, ranging from simple box models to a chemistry-climate model (CCM), UM-UKCA, to assess the contemporary and possible future atmospheric methane burden. We assess two emission data sets for the year 2000 deployed in UM-UKCA against key observational constraints. We explore the impact of the treatment of model boundary conditions for methane and show that, depending on other factors, such as CO emissions, satisfactory agreement may be obtained with either of the CH4 emission data sets, highlighting the difficulty in unambiguous choice of model emissions in a coupled chemistry model with strong feedbacks. The feedbacks in the CH4-CO-OH system, and their uncertainties, play a critical role in the projection of possible futures. In a future driven by large increases in greenhouse gas forcing, increases in tropospheric temperature drive, an increase in water vapor, and, hence, [OH]. In the absence of methane emission changes this leads to a significant decrease in methane compared to the year 2000. However, adding a projected increase in methane emissions from the RCP8.5 scenario leads to a large increase in methane abundance. This is modified by changes to CO and NOx emissions. Clearly, future levels of methane are uncertain and depend critically on climate change and on the future emission pathways of methane and ozone precursors. We highlight that further work is needed to understand the coupled CH4-CO-OH system in order to understand better future methane evolution.
Collapse
Affiliation(s)
- I. Heimann
- Chemistry DepartmentCambridge UniversityCambridgeUK
| | - P. T. Griffiths
- Chemistry DepartmentCambridge UniversityCambridgeUK
- National Centre for Atmospheric ScienceCambridge UniversityCambridgeUK
| | - N. J. Warwick
- Chemistry DepartmentCambridge UniversityCambridgeUK
- National Centre for Atmospheric ScienceCambridge UniversityCambridgeUK
| | - N. L. Abraham
- Chemistry DepartmentCambridge UniversityCambridgeUK
- National Centre for Atmospheric ScienceCambridge UniversityCambridgeUK
| | - A. T. Archibald
- Chemistry DepartmentCambridge UniversityCambridgeUK
- National Centre for Atmospheric ScienceCambridge UniversityCambridgeUK
| | - J. A. Pyle
- Chemistry DepartmentCambridge UniversityCambridgeUK
- National Centre for Atmospheric ScienceCambridge UniversityCambridgeUK
| |
Collapse
|
9
|
Travis KR, Heald CL, Allen HM, Apel EC, Arnold SR, Blake DR, Brune WH, Chen X, Commane R, Crounse JD, Daube BC, Diskin GS, Elkins JW, Evans MJ, Hall SR, Hintsa EJ, Hornbrook RS, Kasibhatla PS, Kim MJ, Luo G, McKain K, Millet DB, Moore FL, Peischl J, Ryerson TB, Sherwen T, Thames AB, Ullmann K, Wang X, Wennberg PO, Wolfe GM, Yu F. Constraining remote oxidation capacity with ATom observations. ATMOSPHERIC CHEMISTRY AND PHYSICS 2020; 20:7753-7781. [PMID: 33688335 PMCID: PMC7939060 DOI: 10.5194/acp-20-7753-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The global oxidation capacity, defined as the tropospheric mean concentration of the hydroxyl radical (OH), controls the lifetime of reactive trace gases in the atmosphere such as methane and carbon monoxide (CO). Models tend to underestimate the methane lifetime and CO concentrations throughout the troposphere, which is consistent with excessive OH. Approximately half of the oxidation of methane and non-methane volatile organic compounds (VOCs) is thought to occur over the oceans where oxidant chemistry has received little validation due to a lack of observational constraints. We use observations from the first two deployments of the NASA ATom aircraft campaign during July-August 2016 and January-February 2017 to evaluate the oxidation capacity over the remote oceans and its representation by the GEOS-Chem chemical transport model. The model successfully simulates the magnitude and vertical profile of remote OH within the measurement uncertainties. Comparisons against the drivers of OH production (water vapor, ozone, and NO y concentrations, ozone photolysis frequencies) also show minimal bias, with the exception of wintertime NO y . The severe model overestimate of NO y during this period may indicate insufficient wet scavenging and/or missing loss on sea-salt aerosols. Large uncertainties in these processes require further study to improve simulated NO y partitioning and removal in the troposphere, but preliminary tests suggest that their overall impact could marginally reduce the model bias in tropospheric OH. During the ATom-1 deployment, OH reactivity (OHR) below 3 km is significantly enhanced, and this is not captured by the sum of its measured components (cOHRobs) or by the model (cOHRmod). This enhancement could suggest missing reactive VOCs but cannot be explained by a comprehensive simulation of both biotic and abiotic ocean sources of VOCs. Additional sources of VOC reactivity in this region are difficult to reconcile with the full suite of ATom measurement constraints. The model generally reproduces the magnitude and seasonality of cOHRobs but underestimates the contribution of oxygenated VOCs, mainly acetaldehyde, which is severely underestimated throughout the troposphere despite its calculated lifetime of less than a day. Missing model acetaldehyde in previous studies was attributed to measurement uncertainties that have been largely resolved. Observations of peroxyacetic acid (PAA) provide new support for remote levels of acetaldehyde. The underestimate in both model acetaldehyde and PAA is present throughout the year in both hemispheres and peaks during Northern Hemisphere summer. The addition of ocean sources of VOCs in the model increases cOHRmod by 3% to 9% and improves model-measurement agreement for acetaldehyde, particularly in winter, but cannot resolve the model summertime bias. Doing so would require 100 Tg yr-1 of a long-lived unknown precursor throughout the year with significant additional emissions in the Northern Hemisphere summer. Improving the model bias for remote acetaldehyde and PAA is unlikely to fully resolve previously reported model global biases in OH and methane lifetime, suggesting that future work should examine the sources and sinks of OH over land.
Collapse
Affiliation(s)
- Katherine R. Travis
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Colette L. Heald
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hannah M. Allen
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Eric C. Apel
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Stephen R. Arnold
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Donald R. Blake
- Department of Chemistry, University of California Irvine, Irvine, CA, USA
| | - William H. Brune
- Department of Meteorology, Pennsylvania State University, University Park, PA, USA
| | - Xin Chen
- University of Minnesota, Department of Soil, Water and Climate, St. Paul, MN, USA
| | - Róisín Commane
- Dept. of Earth & Environmental Sciences of Lamont-Doherty Earth Observatory and Columbia University, Palisades, NY, USA
| | - John D. Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Bruce C. Daube
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | | | - James W. Elkins
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Mathew J. Evans
- Wolfson Atmospheric Chemistry Laboratories (WACL), Department of Chemistry, University of York, York, UK
- National Centre for Atmospheric Science (NCAS), University of York, York, UK
| | - Samuel R. Hall
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Eric J. Hintsa
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Science, University of Colorado, CO, USA
| | - Rebecca S. Hornbrook
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | | | - Michelle J. Kim
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
| | - Gan Luo
- Atmospheric Sciences Research Center, University of Albany, Albany, NY, USA
| | - Kathryn McKain
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Science, University of Colorado, CO, USA
| | - Dylan B. Millet
- University of Minnesota, Department of Soil, Water and Climate, St. Paul, MN, USA
| | - Fred L. Moore
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Science, University of Colorado, CO, USA
| | - Jeffrey Peischl
- Cooperative Institute for Research in Environmental Science, University of Colorado, CO, USA
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Thomas B. Ryerson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Tomás Sherwen
- Wolfson Atmospheric Chemistry Laboratories (WACL), Department of Chemistry, University of York, York, UK
- National Centre for Atmospheric Science (NCAS), University of York, York, UK
| | - Alexander B. Thames
- Department of Meteorology, Pennsylvania State University, University Park, PA, USA
| | - Kirk Ullmann
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Xuan Wang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Paul O. Wennberg
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
| | - Glenn M. Wolfe
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Fangqun Yu
- Atmospheric Sciences Research Center, University of Albany, Albany, NY, USA
| |
Collapse
|
10
|
Wolfe GM, Nicely JM, St Clair JM, Hanisco TF, Liao J, Oman LD, Brune WB, Miller D, Thames A, González Abad G, Ryerson TB, Thompson CR, Peischl J, McCain K, Sweeney C, Wennberg PO, Kim M, Crounse JD, Hall SR, Ullmann K, Diskin G, Bui P, Chang C, Dean-Day J. Mapping hydroxyl variability throughout the global remote troposphere via synthesis of airborne and satellite formaldehyde observations. Proc Natl Acad Sci U S A 2019; 116:11171-11180. [PMID: 31110019 PMCID: PMC6561255 DOI: 10.1073/pnas.1821661116] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hydroxyl radical (OH) fuels tropospheric ozone production and governs the lifetime of methane and many other gases. Existing methods to quantify global OH are limited to annual and global-to-hemispheric averages. Finer resolution is essential for isolating model deficiencies and building process-level understanding. In situ observations from the Atmospheric Tomography (ATom) mission demonstrate that remote tropospheric OH is tightly coupled to the production and loss of formaldehyde (HCHO), a major hydrocarbon oxidation product. Synthesis of this relationship with satellite-based HCHO retrievals and model-derived HCHO loss frequencies yields a map of total-column OH abundance throughout the remote troposphere (up to 70% of tropospheric mass) over the first two ATom missions (August 2016 and February 2017). This dataset offers unique insights on near-global oxidizing capacity. OH exhibits significant seasonality within individual hemispheres, but the domain mean concentration is nearly identical for both seasons (1.03 ± 0.25 × 106 cm-3), and the biseasonal average North/South Hemisphere ratio is 0.89 ± 0.06, consistent with a balance of OH sources and sinks across the remote troposphere. Regional phenomena are also highlighted, such as a 10-fold OH depression in the Tropical West Pacific and enhancements in the East Pacific and South Atlantic. This method is complementary to budget-based global OH constraints and can help elucidate the spatial and temporal variability of OH production and methane loss.
Collapse
Affiliation(s)
- Glenn M Wolfe
- Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, MD 21228;
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771
| | - Julie M Nicely
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740
| | - Jason M St Clair
- Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, MD 21228
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771
| | - Thomas F Hanisco
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771
| | - Jin Liao
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771
- Universities Space Research Association, Columbia, MD 21046
| | - Luke D Oman
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771
| | - William B Brune
- Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, PA 16801
| | - David Miller
- Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, PA 16801
| | - Alexander Thames
- Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, PA 16801
| | | | - Thomas B Ryerson
- Chemical Sciences Division, National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory, Boulder, CO 80305
| | - Chelsea R Thompson
- Chemical Sciences Division, National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Jeff Peischl
- Chemical Sciences Division, National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Kathryn McCain
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO 80305
| | - Colm Sweeney
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO 80305
| | - Paul O Wennberg
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125
| | - Michelle Kim
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - John D Crounse
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Samuel R Hall
- Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO 80307
| | - Kirk Ullmann
- Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO 80307
| | - Glenn Diskin
- Atmospheric Composition, NASA Langley Research Center, Hampton VA 23666
| | - Paul Bui
- Atmospheric Science, NASA Ames Research Center, Moffett Field, CA 94035
| | - Cecilia Chang
- Atmospheric Science, NASA Ames Research Center, Moffett Field, CA 94035
- Bay Area Environmental Research Institute, Moffett Field, CA 94952
| | - Jonathan Dean-Day
- Atmospheric Science, NASA Ames Research Center, Moffett Field, CA 94035
- Bay Area Environmental Research Institute, Moffett Field, CA 94952
| |
Collapse
|
11
|
Wilson SR, Madronich S, Longstreth JD, Solomon KR. Interactive effects of changing stratospheric ozone and climate on tropospheric composition and air quality, and the consequences for human and ecosystem health. Photochem Photobiol Sci 2019; 18:775-803. [PMID: 30810564 DOI: 10.1039/c8pp90064g] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The composition of the air we breathe is determined by emissions, weather, and photochemical transformations induced by solar UV radiation. Photochemical reactions of many emitted chemical compounds can generate important (secondary) pollutants including ground-level ozone (O3) and some particulate matter, known to be detrimental to human health and ecosystems. Poor air quality is the major environmental cause of premature deaths globally, and even a small decrease in air quality can translate into a large increase in the number of deaths. In many regions of the globe, changes in emissions of pollutants have caused significant changes in air quality. Short-term variability in the weather as well as long-term climatic trends can affect ground-level pollution through several mechanisms. These include large-scale changes in the transport of O3 from the stratosphere to the troposphere, winds, clouds, and patterns of precipitation. Long-term trends in UV radiation, particularly related to the depletion and recovery of stratospheric ozone, are also expected to result in changes in air quality as well as the self-cleaning capacity of the global atmosphere. The increased use of substitutes for ozone-depleting substances, in response to the Montreal Protocol, does not currently pose a significant risk to the environment. This includes both the direct emissions of substitutes during use and their atmospheric degradation products (e.g. trifluoroacetic acid, TFA).
Collapse
Affiliation(s)
- S R Wilson
- Centre for Atmospheric Chemistry, School of Earth, Atmosphere and Life Sciences, University of Wollongong, NSW, Australia.
| | - S Madronich
- National Center for Atmospheric Research, Boulder, CO, USA
| | - J D Longstreth
- The Institute for Global Risk Research, LLC, Bethesda, MD, USA and Emergent BioSolutions, Gaithersburg, MD, USA
| | - K R Solomon
- Centre for Toxicology and School of Environmental Sciences, University of Guelph, ON, Canada
| |
Collapse
|
12
|
Turner AJ, Frankenberg C, Kort EA. Interpreting contemporary trends in atmospheric methane. Proc Natl Acad Sci U S A 2019; 116:2805-2813. [PMID: 30733299 PMCID: PMC6386658 DOI: 10.1073/pnas.1814297116] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atmospheric methane plays a major role in controlling climate, yet contemporary methane trends (1982-2017) have defied explanation with numerous, often conflicting, hypotheses proposed in the literature. Specifically, atmospheric observations of methane from 1982 to 2017 have exhibited periods of both increasing concentrations (from 1982 to 2000 and from 2007 to 2017) and stabilization (from 2000 to 2007). Explanations for the increases and stabilization have invoked changes in tropical wetlands, livestock, fossil fuels, biomass burning, and the methane sink. Contradictions in these hypotheses arise because our current observational network cannot unambiguously link recent methane variations to specific sources. This raises some fundamental questions: (i) What do we know about sources, sinks, and underlying processes driving observed trends in atmospheric methane? (ii) How will global methane respond to changes in anthropogenic emissions? And (iii), What future observations could help resolve changes in the methane budget? To address these questions, we discuss potential drivers of atmospheric methane abundances over the last four decades in light of various observational constraints as well as process-based knowledge. While uncertainties in the methane budget exist, they should not detract from the potential of methane emissions mitigation strategies. We show that net-zero cost emission reductions can lead to a declining atmospheric burden, but can take three decades to stabilize. Moving forward, we make recommendations for observations to better constrain contemporary trends in atmospheric methane and to provide mitigation support.
Collapse
Affiliation(s)
- Alexander J Turner
- Department of Earth and Planetary Sciences, University of California, Berkeley, CA 94720;
| | - Christian Frankenberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91226;
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
| | - Eric A Kort
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109
| |
Collapse
|
13
|
Nechita-Banda N, Krol M, van der Werf GR, Kaiser JW, Pandey S, Huijnen V, Clerbaux C, Coheur P, Deeter MN, Röckmann T. Monitoring emissions from the 2015 Indonesian fires using CO satellite data. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0307. [PMID: 30297466 PMCID: PMC6178426 DOI: 10.1098/rstb.2017.0307] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2018] [Indexed: 01/17/2023] Open
Abstract
Southeast Asia, in particular Indonesia, has periodically struggled with intense fire events. These events convert substantial amounts of carbon stored as peat to atmospheric carbon dioxide (CO2) and significantly affect atmospheric composition on a regional to global scale. During the recent 2015 El Niño event, peat fires led to strong enhancements of carbon monoxide (CO), an air pollutant and well-known tracer for biomass burning. These enhancements were clearly observed from space by the Infrared Atmospheric Sounding Interferometer (IASI) and the Measurements of Pollution in the Troposphere (MOPITT) instruments. We use these satellite observations to estimate CO fire emissions within an inverse modelling framework. We find that the derived CO emissions for each sub-region of Indonesia and Papua are substantially different from emission inventories, highlighting uncertainties in bottom-up estimates. CO fire emissions based on either MOPITT or IASI have a similar spatial pattern and evolution in time, and a 10% uncertainty based on a set of sensitivity tests we performed. Thus, CO satellite data have a high potential to complement existing operational fire emission estimates based on satellite observations of fire counts, fire radiative power and burned area, in better constraining fire occurrence and the associated conversion of peat carbon to atmospheric CO2 A total carbon release to the atmosphere of 0.35-0.60 Pg C can be estimated based on our results.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
Collapse
Affiliation(s)
- Narcisa Nechita-Banda
- Institute for Marine and Atmospheric Research Utrecht (IMAU), University of Utrecht, 3584 CC Utrecht, The Netherlands
| | - Maarten Krol
- Institute for Marine and Atmospheric Research Utrecht (IMAU), University of Utrecht, 3584 CC Utrecht, The Netherlands.,Department of Meteorology and Air Quality (MAQ), Wageningen University and Research Centre, 6700 AA Wageningen, The Netherlands.,SRON Netherlands Institute for Space Research, 3584 CA Utrecht, The Netherlands
| | | | - Johannes W Kaiser
- Air Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Sudhanshu Pandey
- SRON Netherlands Institute for Space Research, 3584 CA Utrecht, The Netherlands
| | - Vincent Huijnen
- Royal Netherlands Meteorological Institute (KNMI), 3731 GA De Bilt, The Netherlands
| | - Cathy Clerbaux
- LATMOS/IPSL, Sorbonne Université, Université Paris-Saclay, CNRS, 75252 Paris, France.,Spectroscopie de l'Atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Pierre Coheur
- Spectroscopie de l'Atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Merritt N Deeter
- National Center for Atmospheric Research (NCAR), Boulder, CO 80305, USA
| | - Thomas Röckmann
- Institute for Marine and Atmospheric Research Utrecht (IMAU), University of Utrecht, 3584 CC Utrecht, The Netherlands
| |
Collapse
|
14
|
Liang Q, Chipperfield MP, Fleming EL, Abraham NL, Braesicke P, Burkholder JB, Daniel JS, Dhomse S, Fraser PJ, Hardiman SC, Jackman CH, Kinnison DE, Krummel PB, Montzka SA, Morgenstern O, McCulloch A, Mühle J, Newman PA, Orkin VL, Pitari G, Prinn RG, Rigby M, Rozanov E, Stenke A, Tummon F, Velders GJM, Visioni D, Weiss RF. Deriving Global OH Abundance and Atmospheric Lifetimes for Long-Lived Gases: A Search for CH 3CCl 3 Alternatives. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2017; 122:11914-11933. [PMID: 38515436 PMCID: PMC10956888 DOI: 10.1002/2017jd026926] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
An accurate estimate of global hydroxyl radical (OH) abundance is important for projections of air quality, climate, and stratospheric ozone recovery. As the atmospheric mixing ratios of methyl chloroform (CH3CCl3) (MCF), the commonly used OH reference gas, approaches zero, it is important to find alternative approaches to infer atmospheric OH abundance and variability. The lack of global bottom-up emission inventories is the primary obstacle in choosing a MCF alternative. We illustrate that global emissions of long-lived trace gases can be inferred from their observed mixing ratio differences between the Northern Hemisphere (NH) and Southern Hemisphere (SH), given realistic estimates of their NH-SH exchange time, the emission partitioning between the two hemispheres, and the NH versus SH OH abundance ratio. Using the observed long-term trend and emissions derived from the measured hemispheric gradient, the combination of HFC-32 (CH2F2), HFC-134a (CH2FCF3, HFC-152a (CH3CHF2), and HCFC-22 (CHClF2), instead of a single gas, will be useful as a MCF alternative to infer global and hemispheric OH abundance and trace gas lifetimes. The primary assumption on which this multispecies approach relies is that the OH lifetimes can be estimated by scaling the thermal reaction rates of a reference gas at 272 K on global and hemispheric scales. Thus, the derived hemispheric and global OH estimates are forced to reconcile the observed trends and gradient for all four compounds simultaneously. However, currently, observations of these gases from the surface networks do not provide more accurate OH abundance estimate than that from MCF.
Collapse
Affiliation(s)
- Qing Liang
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Universities Space Research Association, GESTAR, Columbia, Maryland, USA
| | - Martyn P Chipperfield
- National Centre for Earth Observation, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Eric L Fleming
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Science Systems and Applications, Inc, Lanham, Maryland, USA
| | - N Luke Abraham
- National Centre for Atmospheric Science, Leeds, UK
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - James B Burkholder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - John S Daniel
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Sandip Dhomse
- National Centre for Earth Observation, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Paul J Fraser
- Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, Vic, Australia
| | | | - Charles H Jackman
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | | | - Paul B Krummel
- Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, Vic, Australia
| | - Stephen A Montzka
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Olaf Morgenstern
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | | | - Jens Mühle
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA
| | - Paul A Newman
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Vladimir L Orkin
- National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Giovanni Pitari
- Department of Physical and Chemical Sciences, Università dell'Aquila, L'Aquila, Italy
| | - Ronald G Prinn
- Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Matthew Rigby
- School of Chemistry, University of Bristol, Bristol, UK
| | - Eugene Rozanov
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
- Physikalisch-Meteorologisches Observatorium Davos World Radiation Centre, Davos Dorf, Switzerland
| | - Andrea Stenke
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
| | - Fiona Tummon
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
| | - Guus J M Velders
- National Institute for Public Health and the Environment, Bilthoven, Netherlands
- Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands
| | - Daniele Visioni
- Department of Physical and Chemical Sciences, Università dell'Aquila, L'Aquila, Italy
| | - Ray F Weiss
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA
| |
Collapse
|
15
|
Takanabe K, Khan AM, Tang Y, Nguyen L, Ziani A, Jacobs BW, Elbaz AM, Sarathy SM, Tao FF. Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation. Angew Chem Int Ed Engl 2017. [PMID: 28650565 PMCID: PMC5601248 DOI: 10.1002/anie.201704758] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sodium-based catalysts (such as Na2 WO4 ) were proposed to selectively catalyze OH radical formation from H2 O and O2 at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na2 WO4 , which can form OH radicals, using in situ techniques including X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). As a result, Na2 O2 species, which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800 °C, and these species are useful for various gas-phase hydrocarbon reactions, including the selective transformation of methane to ethane.
Collapse
Affiliation(s)
- Kazuhiro Takanabe
- King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center (KCC), Physical Sciences and Engineering Division (PSE), 4700 KAUST, Thuwal, 23955-6900, Saudi Arabia
| | - Abdulaziz M Khan
- King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center (KCC), Physical Sciences and Engineering Division (PSE), 4700 KAUST, Thuwal, 23955-6900, Saudi Arabia
| | - Yu Tang
- Department of Chemical and Petroleum Engineering, Department of Chemistry, University of Kansas, Lawrence, KS, 66045, USA
| | - Luan Nguyen
- Department of Chemical and Petroleum Engineering, Department of Chemistry, University of Kansas, Lawrence, KS, 66045, USA
| | - Ahmed Ziani
- King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center (KCC), Physical Sciences and Engineering Division (PSE), 4700 KAUST, Thuwal, 23955-6900, Saudi Arabia
| | - Benjamin W Jacobs
- Protochips, Inc., 3800 Gateway Centre Blvd #306, Morrisville, NC, 27560, USA.,Analytical Instrumentation Facility, Materials Science and Engineering Department, North Carolina State University, 2410 Campus Shore Dr, Raleigh, NC, 27695, USA
| | - Ayman M Elbaz
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (CCRC) and Physical Sciences and Engineering Division (PSE), 4700 KAUST, Thuwal, 23955-6900, Saudi Arabia.,Mechanical Power Engineering Department, Faculty of Engineering Mataria, Helwan University, Al Sikka Al Hadid Al Gharbeya, Al Masaken Al Iqtisadeyah, Qism Helwan, Cairo Governorate, Egypt
| | - S Mani Sarathy
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (CCRC) and Physical Sciences and Engineering Division (PSE), 4700 KAUST, Thuwal, 23955-6900, Saudi Arabia
| | - Franklin Feng Tao
- Department of Chemical and Petroleum Engineering, Department of Chemistry, University of Kansas, Lawrence, KS, 66045, USA
| |
Collapse
|
16
|
Takanabe K, Khan AM, Tang Y, Nguyen L, Ziani A, Jacobs BW, Elbaz AM, Sarathy SM, Tao FF. Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704758] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kazuhiro Takanabe
- King Abdullah University of Science and Technology (KAUST); KAUST Catalysis Center (KCC); Physical Sciences and Engineering Division (PSE); 4700 KAUST Thuwal 23955-6900 Saudi Arabia
| | - Abdulaziz M. Khan
- King Abdullah University of Science and Technology (KAUST); KAUST Catalysis Center (KCC); Physical Sciences and Engineering Division (PSE); 4700 KAUST Thuwal 23955-6900 Saudi Arabia
| | - Yu Tang
- Department of Chemical and Petroleum Engineering; Department of Chemistry; University of Kansas; Lawrence KS 66045 USA
| | - Luan Nguyen
- Department of Chemical and Petroleum Engineering; Department of Chemistry; University of Kansas; Lawrence KS 66045 USA
| | - Ahmed Ziani
- King Abdullah University of Science and Technology (KAUST); KAUST Catalysis Center (KCC); Physical Sciences and Engineering Division (PSE); 4700 KAUST Thuwal 23955-6900 Saudi Arabia
| | - Benjamin W. Jacobs
- Protochips, Inc.; 3800 Gateway Centre Blvd #306 Morrisville NC 27560 USA
- Analytical Instrumentation Facility; Materials Science and Engineering Department; North Carolina State University; 2410 Campus Shore Dr Raleigh NC 27695 USA
| | - Ayman M. Elbaz
- King Abdullah University of Science and Technology (KAUST); Clean Combustion Research Center (CCRC) and Physical Sciences and Engineering Division (PSE); 4700 KAUST Thuwal 23955-6900 Saudi Arabia
- Mechanical Power Engineering Department; Faculty of Engineering Mataria; Helwan University; Al Sikka Al Hadid Al Gharbeya, Al Masaken Al Iqtisadeyah Qism Helwan Cairo Governorate Egypt
| | - S. Mani Sarathy
- King Abdullah University of Science and Technology (KAUST); Clean Combustion Research Center (CCRC) and Physical Sciences and Engineering Division (PSE); 4700 KAUST Thuwal 23955-6900 Saudi Arabia
| | - Franklin Feng Tao
- Department of Chemical and Petroleum Engineering; Department of Chemistry; University of Kansas; Lawrence KS 66045 USA
| |
Collapse
|
17
|
Ambiguity in the causes for decadal trends in atmospheric methane and hydroxyl. Proc Natl Acad Sci U S A 2017; 114:5367-5372. [PMID: 28416668 DOI: 10.1073/pnas.1616020114] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Methane is the second strongest anthropogenic greenhouse gas and its atmospheric burden has more than doubled since 1850. Methane concentrations stabilized in the early 2000s and began increasing again in 2007. Neither the stabilization nor the recent growth are well understood, as evidenced by multiple competing hypotheses in recent literature. Here we use a multispecies two-box model inversion to jointly constrain 36 y of methane sources and sinks, using ground-based measurements of methane, methyl chloroform, and the C13/C12 ratio in atmospheric methane (δ13CH4) from 1983 through 2015. We find that the problem, as currently formulated, is underdetermined and solutions obtained in previous work are strongly dependent on prior assumptions. Based on our analysis, the mathematically most likely explanation for the renewed growth in atmospheric methane, counterintuitively, involves a 25-Tg/y decrease in methane emissions from 2003 to 2016 that is offset by a 7% decrease in global mean hydroxyl (OH) concentrations, the primary sink for atmospheric methane, over the same period. However, we are still able to fit the observations if we assume that OH concentrations are time invariant (as much of the previous work has assumed) and we then find solutions that are largely consistent with other proposed hypotheses for the renewed growth of atmospheric methane since 2007. We conclude that the current surface observing system does not allow unambiguous attribution of the decadal trends in methane without robust constraints on OH variability, which currently rely purely on methyl chloroform data and its uncertain emissions estimates.
Collapse
|
18
|
Abstract
The growth in global methane (CH4) concentration, which had been ongoing since the industrial revolution, stalled around the year 2000 before resuming globally in 2007. We evaluate the role of the hydroxyl radical (OH), the major CH4 sink, in the recent CH4 growth. We also examine the influence of systematic uncertainties in OH concentrations on CH4 emissions inferred from atmospheric observations. We use observations of 1,1,1-trichloroethane (CH3CCl3), which is lost primarily through reaction with OH, to estimate OH levels as well as CH3CC3 emissions, which have uncertainty that previously limited the accuracy of OH estimates. We find a 64-70% probability that a decline in OH has contributed to the post-2007 methane rise. Our median solution suggests that CH4 emissions increased relatively steadily during the late 1990s and early 2000s, after which growth was more modest. This solution obviates the need for a sudden statistically significant change in total CH4 emissions around the year 2007 to explain the atmospheric observations and can explain some of the decline in the atmospheric 13CH4/12CH4 ratio and the recent growth in C2H6 Our approach indicates that significant OH-related uncertainties in the CH4 budget remain, and we find that it is not possible to implicate, with a high degree of confidence, rapid global CH4 emissions changes as the primary driver of recent trends when our inferred OH trends and these uncertainties are considered.
Collapse
|
19
|
Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015. Photochem Photobiol Sci 2016; 15:141-74. [PMID: 26822392 DOI: 10.1039/c6pp90004f] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, biogeochemistry, air quality, and materials. The Panels provide a detailed assessment report every four years. The most recent 2014 Quadrennial Assessment by the EEAP was published as a special issue of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). The next Quadrennial Assessment will be published in 2018/2019. In the interim, the EEAP generally produces an annual update or progress report of the relevant scientific findings. The present progress report for 2015 assesses some of the highlights and new insights with regard to the interactive nature of the effects of UV radiation, atmospheric processes, and climate change.
Collapse
|
20
|
Gligorovski S, Strekowski R, Barbati S, Vione D. Environmental Implications of Hydroxyl Radicals (•OH). Chem Rev 2015; 115:13051-92. [DOI: 10.1021/cr500310b] [Citation(s) in RCA: 737] [Impact Index Per Article: 81.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sasho Gligorovski
- Aix-Marseille
Université, CNRS, LCE UMR 7376, 13331 Marseilles, France
| | - Rafal Strekowski
- Aix-Marseille
Université, CNRS, LCE UMR 7376, 13331 Marseilles, France
| | - Stephane Barbati
- Aix-Marseille
Université, CNRS, LCE UMR 7376, 13331 Marseilles, France
| | - Davide Vione
- Dipartimento
di Chimica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy
- Centro
Interdipartimentale NatRisk, Università di Torino, Via L. Da
Vinci 44, 10095 Grugliasco, Italy
| |
Collapse
|
21
|
Wang H, Qiu Y, Czakó G, Schaefer HF. Pathways for the OH + Cl2 → HOCl + Cl and HOCl + Cl → HCl + ClO Reactions. J Phys Chem A 2015; 119:7802-9. [PMID: 25965106 DOI: 10.1021/acs.jpca.5b01273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High level coupled-cluster theory, with spin-orbit coupling evaluated via the Breit-Pauli operator in the interacting-states approach, is used to investigate the OH radical reaction with Cl2 and the subsequent reaction HOCl + Cl. The entrance complex, transition state, and exit complex for both reactions have been determined using the CCSD(T) method with correlation consistent basis sets up to cc-pV6Z. Also reported are CCSDT computations. The OH + Cl2 reaction is predicted to be endothermic by 2.2 kcal/mol, compared to the best experiments, 2.0 kcal/mol. The above theoretical results include zero-point vibrational energy corrections and spin-orbit contributions. The activation energy (Ea) of the OH + Cl2 reaction predicted here, 2.3 kcal/mol, could be as much as 1 kcal/mol too high, but it falls among the four experimental Ea values, which span the range 1.1-2.5 kcal/mol. The exothermicity of the second reaction HOCl + Cl → HCl + ClO is 8.4 kcal/mol, compared to experiment 8.7 kcal/mol. The activation energy for latter reaction is unknown experimentally, but predicted here to be large, 11.5 kcal/mol. There are currently no experiments relevant to the theoretical entrance and exit complexes predicted here.
Collapse
Affiliation(s)
- Hongyan Wang
- †School of Physical Science and Technology, Southwest Jiaotong University, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Chengdu 610031, China.,‡Department of Chemistry and Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Yudong Qiu
- ‡Department of Chemistry and Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Gábor Czakó
- §Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös University, P.O. Box 32, H-1518 Budapest 112, Hungary
| | - Henry F Schaefer
- ‡Department of Chemistry and Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|
22
|
Global emissions of refrigerants HCFC-22 and HFC-134a: unforeseen seasonal contributions. Proc Natl Acad Sci U S A 2014; 111:17379-84. [PMID: 25422438 DOI: 10.1073/pnas.1417372111] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HCFC-22 (CHClF2) and HFC-134a (CH2FCF3) are two major gases currently used worldwide in domestic and commercial refrigeration and air conditioning. HCFC-22 contributes to stratospheric ozone depletion, and both species are potent greenhouse gases. In this work, we study in situ observations of HCFC-22 and HFC-134a taken from research aircraft over the Pacific Ocean in a 3-y span [HIaper-Pole-to-Pole Observations (HIPPO) 2009-2011] and combine these data with long-term ground observations from global surface sites [National Oceanic and Atmospheric Administration (NOAA) and Advanced Global Atmospheric Gases Experiment (AGAGE) networks]. We find the global annual emissions of HCFC-22 and HFC-134a have increased substantially over the past two decades. Emissions of HFC-134a are consistently higher compared with the United Nations Framework Convention on Climate Change (UNFCCC) inventory since 2000, by 60% more in recent years (2009-2012). Apart from these decadal emission constraints, we also quantify recent seasonal emission patterns showing that summertime emissions of HCFC-22 and HFC-134a are two to three times higher than wintertime emissions. This unforeseen large seasonal variation indicates that unaccounted mechanisms controlling refrigerant gas emissions are missing in the existing inventory estimates. Possible mechanisms enhancing refrigerant losses in summer are (i) higher vapor pressure in the sealed compartment of the system at summer high temperatures and (ii) more frequent use and service of refrigerators and air conditioners in summer months. Our results suggest that engineering (e.g., better temperature/vibration-resistant system sealing and new system design of more compact/efficient components) and regulatory (e.g., reinforcing system service regulations) steps to improve containment of these gases from working devices could effectively reduce their release to the atmosphere.
Collapse
|
23
|
Affiliation(s)
- Arlene M Fiore
- Department of Earth and Environmental Sciences, Columbia University, and Lamont-Doherty Earth Observatory, Palisades, New York 10964-1000, USA
| |
Collapse
|