scholarly journals Vista-LA: Mapping methane emitting infrastructure in the Los Angeles megacity

2017 ◽  
Author(s):  
Valerie Carranza ◽  
Talha Rafiq ◽  
Isis Frausto-Vicencio ◽  
Francesca Hopkins ◽  
Kristal R. Verhulst ◽  
...  
Keyword(s):  
Los Angeles ◽  
Urban Areas ◽  
Hot Spot ◽  
Complex Mixture ◽  
Methane Emissions ◽  
Point Sources ◽  
Climate Mitigation ◽  
Analysis Tool ◽  
Oak Ridge ◽  
Methane Source

Abstract. Methane is a potent greenhouse gas (GHG) and a critical target of climate mitigation efforts. However, actionable emission reduction efforts are complicated by large uncertainties in the methane budget at relevant scales. Here, we present Vista, a Geographic Information System (GIS)-based approach to map potential methane emissions sources in greater Los Angeles, an area with a dense, complex mixture of sources. The goal of this work is to provide a database that, together with atmospheric observations, improves methane emissions estimates in urban areas with complex infrastructure. We aggregated methane source location information into three sectors (energy, agriculture, and waste) following the frameworks used by the State of California GHG Inventory and the IPCC Guidelines for GHG Reporting. Geospatial modelling was applied to publicly available datasets to precisely geolocate facilities and infrastructure comprising major anthropogenic methane source sectors. The final database, Vista-Los Angeles (LA), is presented as maps of infrastructure known or expected to emit methane. Vista-LA contains over 33,000 features concentrated on <1% of land area in the region. Currently, Vista-LA is used as a planning and analysis tool for atmospheric measurement surveys of methane sources, particularly for airborne remote sensing, and methane “hot-spot” detection using regional observations. This study represents a first step towards developing an accurate, spatially-resolved methane flux estimate for point sources in California’s South Coast Air Basin (SoCAB), with the potential to address discrepancies between bottom-up and top-down methane emissions accounting. The final Vista-LA datasets and associated metadata have been submitted to the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; https://doi.org/10.3334/ORNLDAAC/1525). 

scholarly journals Vista-LA: Mapping methane-emitting infrastructure in the Los Angeles megacity

2018 ◽  
Vol 10 (1) ◽  
pp. 653-676 ◽  
Author(s):  
Valerie Carranza ◽  
Talha Rafiq ◽  
Isis Frausto-Vicencio ◽  
Francesca M. Hopkins ◽  
Kristal R. Verhulst ◽  
...  
Keyword(s):  
Los Angeles ◽  
Urban Areas ◽  
National Laboratory ◽  
Complex Mixture ◽  
Methane Emissions ◽  
Point Sources ◽  
Climate Mitigation ◽  
Analysis Tool ◽  
Oak Ridge ◽  
Methane Source

Abstract. Methane (CH4) is a potent greenhouse gas (GHG) and a critical target of climate mitigation efforts. However, actionable emission reduction efforts are complicated by large uncertainties in the methane budget on relevant scales. Here, we present Vista, a Geographic Information System (GIS)-based approach to map potential methane emissions sources in the South Coast Air Basin (SoCAB) that encompasses Los Angeles, an area with a dense, complex mixture of methane sources. The goal of this work is to provide a database that, together with atmospheric observations, improves methane emissions estimates in urban areas with complex infrastructure. We aggregated methane source location information into three sectors (energy, agriculture, and waste) following the frameworks used by the State of California GHG Inventory and the Intergovernmental Panel on Climate Change (IPCC) Guidelines for GHG Reporting. Geospatial modeling was applied to publicly available datasets to precisely geolocate facilities and infrastructure comprising major anthropogenic methane source sectors. The final database, Vista-Los Angeles (Vista-LA), is presented as maps of infrastructure known or expected to emit CH4. Vista-LA contains over 33 000 features concentrated on  <  1 % of land area in the region. Currently, Vista-LA is used as a planning and analysis tool for atmospheric measurement surveys of methane sources, particularly for airborne remote sensing, and methane hotspot detection using regional observations. This study represents a first step towards developing an accurate, spatially resolved methane flux estimate for point sources in SoCAB, with the potential to address discrepancies between bottom–up and top–down methane emissions accounting in this region. The Vista-LA datasets and associated metadata are available from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; https://doi.org/10.3334/ORNLDAAC/1525).

Characteristics of urban street level methane emissions in Bucharest, Romania

2020 ◽  
Author(s):  
Julianne Fernandez ◽  
James France ◽  
Malika Menoud ◽  
Hossein Maazallahi ◽  
Marius-Paul Corbu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Greenhouse Gases ◽  
Distribution System ◽  
Urban Areas ◽  
Methane Emissions ◽  
Point Sources ◽  
Measuring Instruments ◽  
High Concentration ◽  
Street Level ◽  
Gas Leaks

&lt;p&gt;Romania has a complex geological history resulting in a very hydrocarbon rich region that is heavily exploited and utilised. Romania&amp;#8217;s Fourth Biennial Report under the UNFCCC states that methane (CH&lt;sub&gt;4&lt;/sub&gt;) emissions have decreased by 61% between 1989 and 2017, which is a result of decreases in fugitive fossil fuel and livestock emissions. Although there is a decreasing trend of CH&lt;sub&gt;4&lt;/sub&gt; levels in most of Europe, we still see an overall increase in atmospheric CH&lt;sub&gt;4&lt;/sub&gt; concentrations. As atmospheric CH&lt;sub&gt;4&lt;/sub&gt; continues to increase and the mitigation of greenhouse gases becomes more of a concern, it is important to address CH&lt;sub&gt;4&lt;/sub&gt; emissions from large cities.&amp;#160; Here we ask the question: What are the major sources of urban methane emissions in Romania&amp;#8217;s city capital, Bucharest? Together, street level continuous measurements of CH&lt;sub&gt;4&lt;/sub&gt; and ethane (C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;), and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C-CH&lt;sub&gt;4&lt;/sub&gt; &amp; &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H-CH&lt;sub&gt;4&lt;/sub&gt; of high concentration plumes assist in the identification of emissions, both for major point sources and small leaks from the natural gas distribution system.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Urban focused surveys were conducted in Bucharest during August of 2019. Three continuously-measuring instruments were used, including an LGR Ultraportable CH&lt;sub&gt;4&lt;/sub&gt;/C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt; analyzer, allowing for the separation of natural gas leaks from other source category emissions. CH&lt;sub&gt;4&lt;/sub&gt; and C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt; have been mapped to find locations of elevated mixing ratios above background. Air samples were collected from an inlet on the vehicle bumper (60 cm above ground) that is connected to a bag pump, filling 3L Flexfoil bags.&amp;#160; Samples were then analyzed for &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C-CH&lt;sub&gt;4&lt;/sub&gt; &amp; &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H-CH&lt;sub&gt;4&lt;/sub&gt; using an IsoPrime Trace Gas continuous flow gas chromatograph isotope ratio mass spectrometer (CF GC-IRMS) at Royal Holloway, University of London and a Thermo Fisher Delta Plus XP, at Utrecht University. Background baselines of CH&lt;sub&gt;4&lt;/sub&gt; and isotopic ratios were statistically determined while traveling and distinguished from the various plumes of high concentrations. Point source signatures were then calculated using Keeling plot analysis. C&lt;sub&gt;2&lt;/sub&gt;:C&lt;sub&gt;1&lt;/sub&gt; ratios from specific emissions types were compared with the correlated &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;CH4&lt;/sub&gt; values.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Detailed urban methane mapping and the use of high precision isotopic source signature measurements provide an efficient approach to identifying and sourcing small gas leaks in urban cities. These results will be useful in future government regulation of greenhouse gas emissions in urban areas as the EU continues to work on the reduction of greenhouse gases.&lt;/p&gt;

A multi-tiered methane analytic framework for constraining budgets, point source attribution, and anomalous event detection

2020 ◽  
Author(s):  
Daniel Cusworth ◽  
Riley Duren ◽  
Andrew Thorpe ◽  
Natasha Stavros ◽  
Brian Bue ◽  
...  
Keyword(s):  
Los Angeles ◽  
Point Source ◽  
Methane Flux ◽  
Global Scale ◽  
Methane Emissions ◽  
Point Sources ◽  
Analytic Framework ◽  
Source Attribution ◽  
Surface Measurements ◽  
New Generation

&lt;p&gt;Methane emissions monitoring is rapidly expanding with increasing coverage of surface, airborne, and satellite instruments. However, no single methane instrument or observing strategy can both close emission budgets and pinpoint point sources on regional to global scales. Instead, we present a multi-tiered data analytics system that synthesizes information across various instruments into a single analytic framework. We highlight an example in Los Angeles, where we combine surface measurements from the Los Angeles megacities project, mountaintop measurements from the CLARS-FTS instrument, airborne AVIRIS-NG point source emission estimates, and TROPOMI total column retrievals into a single analytic framework. Surface, mountaintop, and satellite measurements are assimilated into a methane flux inverse model to constrain basin-wide emissions and pinpoint sub-basin methane hotspots. We show an example of a large urban landfill, whose anomalous emissions were detected by the inverse system, and validated using AVIRIS-NG methane plume maps. This general approach of quantifying both methane area and point source emissions is an avenue not just for closing regional to global scale budgets, but also for understanding which emission sources dominate the budget (i.e., so called methane super-emitters). We finally show how this multi-tiered analytic framework can be improved with future satellite missions, and present examples of unexpectedly large methane emissions that were detected by a new generation of satellite imaging spectrometers.&lt;/p&gt;

scholarly journals Estimating global and North American methane emissions with high spatial resolution using GOSAT satellite data

2015 ◽  
Vol 15 (12) ◽  
pp. 7049-7069 ◽  
Author(s):  
A. J. Turner ◽  
D. J. Jacob ◽  
K. J. Wecht ◽  
J. D. Maasakkers ◽  
E. Lundgren ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
North American ◽  
Transport Model ◽  
Central Valley ◽  
Methane Emissions ◽  
Point Sources ◽  
Atmospheric Methane ◽  
Chemical Transport Model ◽  
Error Characterization ◽  
Methane Source

Abstract. We use 2009–2011 space-borne methane observations from the Greenhouse Gases Observing SATellite (GOSAT) to estimate global and North American methane emissions with 4° × 5° and up to 50 km × 50 km spatial resolution, respectively. GEOS-Chem and GOSAT data are first evaluated with atmospheric methane observations from surface and tower networks (NOAA/ESRL, TCCON) and aircraft (NOAA/ESRL, HIPPO), using the GEOS-Chem chemical transport model as a platform to facilitate comparison of GOSAT with in situ data. This identifies a high-latitude bias between the GOSAT data and GEOS-Chem that we correct via quadratic regression. Our global adjoint-based inversion yields a total methane source of 539 Tg a−1 with some important regional corrections to the EDGARv4.2 inventory used as a prior. Results serve as dynamic boundary conditions for an analytical inversion of North American methane emissions using radial basis functions to achieve high resolution of large sources and provide error characterization. We infer a US anthropogenic methane source of 40.2–42.7 Tg a−1, as compared to 24.9–27.0 Tg a−1 in the EDGAR and EPA bottom-up inventories, and 30.0–44.5 Tg a−1 in recent inverse studies. Our estimate is supported by independent surface and aircraft data and by previous inverse studies for California. We find that the emissions are highest in the southern–central US, the Central Valley of California, and Florida wetlands; large isolated point sources such as the US Four Corners also contribute. Using prior information on source locations, we attribute 29–44 % of US anthropogenic methane emissions to livestock, 22–31 % to oil/gas, 20 % to landfills/wastewater, and 11–15 % to coal. Wetlands contribute an additional 9.0–10.1 Tg a−1.

scholarly journals Estimating global and North American methane emissions with high spatial resolution using GOSAT satellite data

2015 ◽  
Vol 15 (4) ◽  
pp. 4495-4536 ◽  
Author(s):  
A. J. Turner ◽  
D. J. Jacob ◽  
K. J. Wecht ◽  
J. D. Maasakkers ◽  
S. C. Biraud ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
North American ◽  
Transport Model ◽  
Methane Emissions ◽  
Point Sources ◽  
Atmospheric Methane ◽  
South Central ◽  
Error Characterization ◽  
Methane Source ◽  
Aircraft Data

Abstract. We use 2009–2011 space-borne methane observations from the Greenhouse Gases Observing SATellite (GOSAT) to constrain global and North American inversions of methane emissions with 4° × 5° and up to 50 km × 50 km spatial resolution, respectively. The GOSAT data are first evaluated with atmospheric methane observations from surface networks (NOAA, TCCON) and aircraft (NOAA/DOE, HIPPO), using the GEOS-Chem chemical transport model as a platform to facilitate comparison of GOSAT with in situ data. This identifies a high-latitude bias between the GOSAT data and GEOS-Chem that we correct via quadratic regression. The surface and aircraft data are subsequently used for independent evaluation of the methane source inversions. Our global adjoint-based inversion yields a total methane source of 539 Tg a−1 and points to a large East Asian overestimate in the EDGARv4.2 inventory used as a prior. Results serve as dynamic boundary conditions for an analytical inversion of North American methane emissions using radial basis functions to achieve high resolution of large sources and provide full error characterization. We infer a US anthropogenic methane source of 40.2–42.7 Tg a−1, as compared to 24.9–27.0 Tg a−1 in the EDGAR and EPA bottom-up inventories, and 30.0–44.5 Tg a−1 in recent inverse studies. Our estimate is supported by independent surface and aircraft data and by previous inverse studies for California. We find that the emissions are highest in the South-Central US, the Central Valley of California, and Florida wetlands, large isolated point sources such as the US Four Corners also contribute. We attribute 29–44% of US anthropogenic methane emissions to livestock, 22–31% to oil/gas, 20% to landfills/waste water, and 11–15% to coal with an additional 9.0–10.1 Tg a−1 source from wetlands.

scholarly journals Findings From the Understanding Patterns of Healthy Aging Among Men Who Have Sex With Men Project

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 823-824
Author(s):  
Mark Brennan-Ing ◽  
Michael Plankey ◽  
Deborah Gustafson
Keyword(s):  
Los Angeles ◽  
Urban Areas ◽  
Healthy Aging ◽  
Research Policy ◽  
Disease Risk ◽  
Well Being ◽  
Hiv Status ◽  
Gay Community ◽  
Regulatory Strategies ◽  
Sex With Men

Abstract In 1984, the Multicenter AIDS Cohort Study (MACS) was started to identify factors in the HIV epidemic related to disease risk and treatment progression among gay, bisexual, and other men who have sex with men (MSM) in four urban areas in the US: Baltimore, MD/Washington, D.C.; Chicago, IL; Pittsburgh, PA, and Los Angeles, CA. MACS participants complete biannual study visits involving HIV testing, biometric screenings, and psychosocial data collection. In 2015 a MACS sub-study, the Understanding Patterns of Healthy Aging among MSM Project (HAMSM), was started to better understand resiliencies promoting well-being among MSM age 40 and older, including those with HIV. HAMSM has helped us to understand aging trajectories among MSM, and provides a unique combination of physiological and psychosocial data that can inform efforts to support MSM in healthy aging. This symposium will present emerging findings from the HAMSM study. Our first paper examines the relationships between psychological connection to the gay community (PSOC) and developmental regulatory strategies associated with health behaviors and more positive self-appraisals. The second paper examines how PSOC is related to HIV risk reduction behaviors, and if there are differences in such behaviors based on HIV status. Our third paper considers how self-perceptions of aging (age discrepancy, aging satisfaction) are related to frailty and frailty transitions, and if these relationships differ by HIV status. The final paper examines the relationship of social support to frailty among MSM by HIV status. Implications of these findings for research, policy, and programs targeting MSM will be discussed.

scholarly journals Prediction of Hourly Effect of Land Use on Crime

2018 ◽  
Vol 8 (1) ◽  
pp. 16 ◽  
Author(s):  
Irina Matijosaitiene ◽  
Peng Zhao ◽  
Sylvain Jaume ◽  
Joseph Gilkey Jr
Keyword(s):  
Machine Learning ◽  
Land Use ◽  
Logistic Regression ◽  
Hot Spots ◽  
Urban Areas ◽  
Prediction Models ◽  
Hot Spot ◽  
Time Range ◽  
Land Uses ◽  
Police Departments

Predicting the exact urban places where crime is most likely to occur is one of the greatest interests for Police Departments. Therefore, the goal of the research presented in this paper is to identify specific urban areas where a crime could happen in Manhattan, NY for every hour of a day. The outputs from this research are the following: (i) predicted land uses that generates the top three most committed crimes in Manhattan, by using machine learning (random forest and logistic regression), (ii) identifying the exact hours when most of the assaults are committed, together with hot spots during these hours, by applying time series and hot spot analysis, (iii) built hourly prediction models for assaults based on the land use, by deploying logistic regression. Assault, as a physical attack on someone, according to criminal law, is identified as the third most committed crime in Manhattan. Land use (residential, commercial, recreational, mixed use etc.) is assigned to every area or lot in Manhattan, determining the actual use or activities within each particular lot. While plotting assaults on the map for every hour, this investigation has identified that the hot spots where assaults occur were ‘moving’ and not confined to specific lots within Manhattan. This raises a number of questions: Why are hot spots of assaults not static in an urban environment? What makes them ‘move’—is it a particular urban pattern? Is the ‘movement’ of hot spots related to human activities during the day and night? Answering these questions helps to build the initial frame for assault prediction within every hour of a day. Knowing a specific land use vulnerability to assault during each exact hour can assist the police departments to allocate forces during those hours in risky areas. For the analysis, the study is using two datasets: a crime dataset with geographical locations of crime, date and time, and a geographic dataset about land uses with land use codes for every lot, each obtained from open databases. The study joins two datasets based on the spatial location and classifies data into 24 classes, based on the time range when the assault occurred. Machine learning methods reveal the effect of land uses on larceny, harassment and assault, the three most committed crimes in Manhattan. Finally, logistic regression provides hourly prediction models and unveils the type of land use where assaults could occur during each hour for both day and night.

Toward CO2 and CH4 measurements by ground-based observations of surface-scattered sunlight

2021 ◽  
Author(s):  
Benedikt Hemmer ◽  
Christin Proß ◽  
Stanley P. Sander ◽  
Thomas J. Pongetti ◽  
Zhao-Cheng Zeng ◽  
...  
Keyword(s):  
Los Angeles ◽  
Urban Areas ◽  
Near Infrared ◽  
Chem Phys ◽  
Retrieval Algorithm ◽  
Los Angeles Basin ◽  
Satellite Measurements ◽  
Precise Knowledge ◽  
Extended Sources

&lt;div&gt; &lt;div&gt;Precise knowledge of sources and sinks in the carbon cycle is desired to understand its sensitivity to climate change and to account and verify man-made emissions. In this context, extended sources like urban areas play an important role. While in-situ measurements of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) and methane (CH&lt;sub&gt;4&lt;/sub&gt;) are highly accurate but localized, satellites measure column-integrated concentrations over an extended footprint. The CLARS-FTS [1, 2] stationed at the Mt. Wilson observatory looking downward into the Los Angeles basin has pioneered an innovative measurement technique that fills the sensitivity gap between in-situ and satellite measurements. The technique enables mapping the urban greenhouse gas concentration fields by collecting spectra of ground scattered sunlight and scanning through the region.&lt;/div&gt; &lt;div&gt;&amp;#160;&lt;/div&gt; &lt;div&gt;Here, we report on progress developing a portable setup for a CLARS-FTS-like measurement geometry. The instrument is based on the EM27/SUN FTS with a modified pointing technique and a more sensitive detector. The retrieval algorithm is based on the RemoTeC software, previously employed for solar backscatter satellite measurements. We discuss first steps in terms of instrument performance and retrieval exercises. For the latter, we have carried out simulations on how the neglect of scattering by the retrieval affects the retrieved boundary layer concentrations of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; for an ensemble of hypothetical scenes with variable complexity in aeorsol loadings and viewing geometry. We also report on a test to apply RemoTeC to a small set of CLARS-FTS spectra collected throughout the Los Angeles basin.&lt;/div&gt; &lt;div&gt;&amp;#160;&lt;/div&gt; &lt;div&gt;&lt;em&gt;References&lt;/em&gt;&lt;/div&gt; &lt;div&gt;[1] Fu, D. et al., 2014: Near-infrared remote sensing of Los Angeles trace gas distributions from a mountaintop site, Atmos. Meas. Tech., 7, 713&amp;#8211;729, https://doi.org/10.5194/amt-7-713-2014&lt;/div&gt; [2] Wong, K. W. et al., 2015: Mapping CH4 : CO2 ratios in Los Angeles with CLARS-FTS from Mount Wilson, California, Atmos. Chem. Phys., 15, 241&amp;#8211;252, https://doi.org/10.5194/acp-15-241-2015&lt;/div&gt;

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