Evaluating a high-resolution urban fossil CO2 emissions inventory using eddy-covariance flux measurements and source partitioning

2021 ◽  
Author(s):  
Kai Wu ◽  
Kenneth J. Davis ◽  
Natasha L. Miles ◽  
Scott J. Richardson ◽  
Thomas Lauvaux ◽  
...  
Keyword(s):  
High Resolution ◽  
Eddy Covariance ◽  
Co2 Emissions ◽  
Emissions Inventory ◽  
Flux Measurements ◽  
Source Partitioning

scholarly journals Chemically-resolved aerosol eddy covariance flux measurements in urban Mexico City during MILAGRO 2006

2012 ◽  
Vol 12 (16) ◽  
pp. 7809-7823 ◽  
Author(s):  
R. Zalakeviciute ◽  
M. L. Alexander ◽  
E. Allwine ◽  
J. L. Jimenez ◽  
B. T. Jobson ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Mexico City ◽  
Atmospheric Aerosols ◽  
Emission Inventory ◽  
Urban Landscape ◽  
Organic Aerosol ◽  
Emission Rates ◽  
Eddy Covariance Method ◽  
Emissions Inventory ◽  
Flux Measurements

Abstract. As part of the MILAGRO 2006 field campaign, the exchange of atmospheric aerosols with the urban landscape was measured from a tall tower erected in a heavily populated neighborhood of Mexico City. Urban submicron aerosol fluxes were measured using an eddy covariance method with a quadrupole aerosol mass spectrometer during a two week period in March, 2006. Nitrate and ammonium aerosol concentrations were elevated at this location near the city center compared to measurements at other urban sites. Significant downward fluxes of nitrate aerosol, averaging −0.2 μg m−2 s−1, were measured during daytime. The urban surface was not a significant source of sulfate aerosols. The measurements also showed that primary organic aerosol fluxes, approximated by hydrocarbon-like organic aerosols (HOA), displayed diurnal patterns similar to CO2 fluxes and anthropogenic urban activities. Overall, 47% of submicron organic aerosol emissions were HOA, 35% were oxygenated (OOA) and 18% were associated with biomass burning (BBOA). Organic aerosol fluxes were bi-directional, but on average HOA fluxes were 0.1 μg m−2 s−1, OOA fluxes were −0.03 μg m−2 s−1, and BBOA fluxes were −0.03 μg m−2 s−1. After accounting for size differences (PM1 vs PM2.5) and using an estimate of the black carbon component, comparison of the flux measurements with the 2006 gridded emissions inventory of Mexico City, showed that the daily-averaged total PM emission rates were essentially identical for the emission inventory and the flux measurements. However, the emission inventory included dust and metal particulate contributions, which were not included in the flux measurements. As a result, it appears that the inventory underestimates overall PM emissions for this location.

Improving high resolution emission inventories with local proxies and urban eddy covariance flux measurements

2015 ◽  
Vol 115 ◽  
pp. 246-256 ◽  
Author(s):  
Beniamino Gioli ◽  
Giovanni Gualtieri ◽  
Caterina Busillo ◽  
Francesca Calastrini ◽  
Alessandro Zaldei ◽  
...  
Keyword(s):  
High Resolution ◽  
Eddy Covariance ◽  
Emission Inventories ◽  
Flux Measurements

scholarly journals Eddy covariance flux measurements of pollutant gases in urban Mexico City

2009 ◽  
Vol 9 (19) ◽  
pp. 7325-7342 ◽  
Author(s):  
E. Velasco ◽  
S. Pressley ◽  
R. Grivicke ◽  
E. Allwine ◽  
T. Coons ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Mexico City ◽  
Atmospheric Chemistry ◽  
Anthropogenic Activities ◽  
Flux Measurement ◽  
Proton Transfer Reaction ◽  
Surface Exchange ◽  
Emissions Inventory ◽  
Flux Measurements ◽  
Local Emissions

Abstract. Eddy covariance (EC) flux measurements of the atmosphere/surface exchange of gases over an urban area are a direct way to improve and evaluate emissions inventories, and, in turn, to better understand urban atmospheric chemistry and the role that cities play in regional and global chemical cycles. As part of the MCMA-2003 study, we demonstrated the feasibility of using eddy covariance techniques to measure fluxes of selected volatile organic compounds (VOCs) and CO2 from a residential district of Mexico City (Velasco et al., 2005a, b). During the MILAGRO/MCMA-2006 field campaign, a second flux measurement study was conducted in a different district of Mexico City to corroborate the 2003 flux measurements, to expand the number of species measured, and to obtain additional data for evaluation of the local emissions inventory. Fluxes of CO2 and olefins were measured by the conventional EC technique using an open path CO2 sensor and a Fast Isoprene Sensor calibrated with a propylene standard. In addition, fluxes of toluene, benzene, methanol and C2-benzenes were measured using a virtual disjunct EC method with a Proton Transfer Reaction Mass Spectrometer. The flux measurements were analyzed in terms of diurnal patterns and vehicular activity and were compared with the most recent gridded local emissions inventory. In both studies, the results showed that the urban surface of Mexico City is a net source of CO2 and VOCs with significant contributions from vehicular traffic. Evaporative emissions from commercial and other anthropogenic activities were significant sources of toluene and methanol. The results show that the emissions inventory is in reasonable agreement with measured olefin and CO2 fluxes, while C2-benzenes and toluene emissions from evaporative sources are overestimated in the inventory. It appears that methanol emissions from mobile sources occur, but are not reported in the mobile emissions inventory.

scholarly journals Chemically-resolved aerosol eddy covariance flux measurements in urban Mexico City during MILAGRO 2006

2012 ◽  
Vol 12 (5) ◽  
pp. 11899-11939
Author(s):  
R. Zalakeviciute ◽  
M. L. Alexander ◽  
E. Allwine ◽  
J. L. Jimenez ◽  
B. T. Jobson ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Mexico City ◽  
Atmospheric Aerosols ◽  
Urban Landscape ◽  
Organic Aerosol ◽  
Eddy Covariance Method ◽  
Emissions Inventory ◽  
Aerosol Mass ◽  
Flux Measurements ◽  
Aerosol Emissions

Abstract. As part of the MILAGRO 2006 field campaign, the exchange of atmospheric aerosols with the urban landscape was measured from a tall tower erected in a heavily populated neighborhood of Mexico City. Urban submicron aerosol fluxes were measured using an eddy covariance method with a quadrupole aerosol mass spectrometer during a two week period in March 2006. Nitrate and ammonium aerosol concentrations were elevated at this location near the city center compared to measurements at other urban sites. Significant downward fluxes of nitrate aerosol, averaging −0.2 μg m−2 s−1, were measured during daytime. The urban surface was not a significant source of sulfate aerosols. The measurements also showed that primary organic aerosol fluxes, approximated by hydrocarbon-like organic aerosols (HOA), displayed diurnal patterns similar to CO2 fluxes and anthropogenic urban activities. Overall, 47% of submicron organic aerosol emissions were HOA, 35% were oxygenated (OOA) and 18% were associated with biomass burning (BBOA). Organic aerosol fluxes were bi-directional, but on average HOA fluxes were 0.09 μg m−2 s−1, OOA fluxes were −0.002 μg m−2 s−1, and BBOA fluxes were −0.03 μg m−2 s−1. The average diurnal flux results showed that the 2006 gridded emissions inventory of Mexico City underestimates mid-day and evening rush hour emissions of submicron aerosols for the monitored neighborhood, but averaged daily, the emission inventory and flux measurements for this location were in close agreement.

scholarly journals Eddy covariance flux measurements of pollutant gases in urban Mexico City

2009 ◽  
Vol 9 (2) ◽  
pp. 7991-8034 ◽  
Author(s):  
E. Velasco ◽  
S. Pressley ◽  
R. Grivicke ◽  
E. Allwine ◽  
T. Coons ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Mexico City ◽  
Atmospheric Chemistry ◽  
Anthropogenic Activities ◽  
Flux Measurement ◽  
Proton Transfer Reaction ◽  
Surface Exchange ◽  
Emissions Inventory ◽  
Flux Measurements ◽  
Residential District

Abstract. Eddy covariance (EC) flux measurements of the atmosphere/surface exchange of gases over an urban area are a direct way to improve and evaluate emissions inventories, and, in turn, to better understand urban atmospheric chemistry and the role that cities play in regional and global chemical cycles. As part of the MCMA-2003 study, we demonstrated the feasibility of using eddy covariance techniques to measure fluxes of selected volatile organic compounds (VOCs) and CO2 from a residential district of Mexico City (Velasco et al., 2005a, b). During the MILAGRO/MCMA-2006 field campaign, a second flux measurement study was conducted in a different district of Mexico City to corroborate the 2003 flux measurements, to expand the number of species measured, and to obtain additional data for evaluation of the local emissions inventory. Fluxes of CO2 and olefins were measured by the conventional EC technique using an open path CO2 sensor and a Fast Isoprene Sensor calibrated with a propylene standard. In addition, fluxes of toluene, benzene, methanol and C2-benzenes were measured using a virtual disjunct EC method with a Proton Transfer Reaction Mass Spectrometer. The flux measurements were analyzed in terms of diurnal patterns and vehicular activity and were compared with the most recent gridded emissions inventory. In both studies, the results showed that the urban surface of Mexico City is a net source of CO2 and VOCs with significant contributions from vehicular traffic. Evaporative emissions from commercial and other anthropogenic activities were significant sources of toluene and methanol. The data show that the emissions inventory is in reasonable agreement with measured olefin and CO2 fluxes, while C2-benzenes and toluene emissions from evaporative sources are overestimated in the inventory. It appears that methanol emissions from mobile sources occur, but are not present in the mobile emissions inventory.

Eddy Covariance measurements and source partitioning of CO2 emissions in an urban environment: Application for Heraklion, Greece

2019 ◽  
Vol 201 ◽  
pp. 278-292 ◽  
Author(s):  
Stavros Stagakis ◽  
Nektarios Chrysoulakis ◽  
Nektarios Spyridakis ◽  
Christian Feigenwinter ◽  
Roland Vogt
Keyword(s):  
Urban Environment ◽  
Eddy Covariance ◽  
Co2 Emissions ◽  
Eddy Covariance Measurements ◽  
Source Partitioning

scholarly journals Eddy covariance flux measurements confirm extreme CH<sub>4</sub> emissions from a Swiss hydropower reservoir and resolve their short-term variability

2011 ◽  
Vol 8 (9) ◽  
pp. 2815-2831 ◽  
Author(s):  
W. Eugster ◽  
T. DelSontro ◽  
S. Sobek
Keyword(s):  
Greenhouse Gas ◽  
Eddy Covariance ◽  
Land Surface ◽  
Lake Level ◽  
Driving Forces ◽  
Open Water ◽  
Short Term ◽  
Flux Measurements ◽  
Floating Chamber ◽  
Hydropower Reservoir

Abstract. Greenhouse gas budgets quantified via land-surface eddy covariance (EC) flux sites differ significantly from those obtained via inverse modeling. A possible reason for the discrepancy between methods may be our gap in quantitative knowledge of methane (CH4) fluxes. In this study we carried out EC flux measurements during two intensive campaigns in summer 2008 to quantify methane flux from a hydropower reservoir and link its temporal variability to environmental driving forces: water temperature and pressure changes (atmospheric and due to changes in lake level). Methane fluxes were extremely high and highly variable, but consistently showed gas efflux from the lake when the wind was approaching the EC sensors across the open water, as confirmed by floating chamber flux measurements. The average flux was 3.8 ± 0.4 μg C m−2 s−1 (mean ± SE) with a median of 1.4 μg C m−2 s−1, which is quite high even compared to tropical reservoirs. Floating chamber fluxes from four selected days confirmed such high fluxes with 7.4 ± 1.3 μg C m−2 s−1. Fluxes increased exponentially with increasing temperatures, but were decreasing exponentially with increasing atmospheric and/or lake level pressure. A multiple regression using lake surface temperatures (0.1 m depth), temperature at depth (10 m deep in front of the dam), atmospheric pressure, and lake level was able to explain 35.4% of the overall variance. This best fit included each variable averaged over a 9-h moving window, plus the respective short-term residuals thereof. We estimate that an annual average of 3% of the particulate organic matter (POM) input via the river is sufficient to sustain these large CH4 fluxes. To compensate the global warming potential associated with the CH4 effluxes from this hydropower reservoir a 1.3 to 3.7 times larger terrestrial area with net carbon dioxide uptake is needed if a European-scale compilation of grasslands, croplands and forests is taken as reference. This indicates the potential relevance of temperate reservoirs and lakes in local and regional greenhouse gas budgets.

Eddy covariance flux measurements of momentum, heat and carbon dioxide in Hudson Bay at the onset of sea ice melt 

2021 ◽  
Author(s):  
Richard Sims ◽  
Brian Butterworth ◽  
Tim Papakyriakou ◽  
Mohamed Ahmed ◽  
Brent Else
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Sea Ice ◽  
Eddy Covariance ◽  
Open Water ◽  
The Arctic ◽  
Gas Transfer ◽  
Hudson Bay ◽  
Flux Measurements ◽  
Ice Fraction

&lt;p&gt;Remoteness and tough conditions have made the Arctic Ocean historically difficult to access; until recently this has resulted in an undersampling of trace gas and gas exchange measurements. The seasonal cycle of sea ice completely transforms the air sea interface and the dynamics of gas exchange. To make estimates of gas exchange in the presence of sea ice, sea ice fraction is frequently used to scale open water gas transfer parametrisations. It remains unclear whether this scaling is appropriate for all sea ice regions. Ship based eddy covariance measurements were made in Hudson Bay during the summer of 2018 from the icebreaker CCGS Amundsen. We will present fluxes of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;), heat and momentum and will show how they change around the Hudson Bay polynya under varying sea ice conditions. We will explore how these fluxes change with wind speed and sea ice fraction. As freshwater stratification was encountered during the cruise, we will compare our measurements with other recent eddy covariance flux measurements made from icebreakers and also will compare our turbulent CO&lt;sub&gt;2&amp;#160;&lt;/sub&gt;fluxes with bulk fluxes calculated using underway and surface bottle pCO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;data.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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