Alexander J. Turner
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View article: Emulating chemistry-climate dynamics with a linear inverse model
Emulating chemistry-climate dynamics with a linear inverse model Open
Coupled chemistry–climate models (CCMs) are powerful tools for investigating chemical variability in the climate system, but high computational cost limits their use for hypothesis testing and adequately sampling variability on long timesc…
View article: Atmospheric Feedbacks Reverse the Sensitivity of Modeled Photosynthesis to Stomatal Function
Atmospheric Feedbacks Reverse the Sensitivity of Modeled Photosynthesis to Stomatal Function Open
Stomata mediate fluxes of carbon and water between terrestrial plants and the atmosphere. These fluxes are governed by stomatal function and can be modulated in many Earth system models by an empirical parameter within the calculation of s…
View article: Modeling Optimal Pathways to a Triple Win in Air Quality, Climate, and Equity
Modeling Optimal Pathways to a Triple Win in Air Quality, Climate, and Equity Open
“Triple win” strategies in air quality are those that benefit health, climate, and equity. Traditional air pollution modeling estimates these outcomes based on simulated changes in emissions. Here, we develop an inverse modeling approach t…
View article: State-wide California 2020 carbon dioxide budget estimated with OCO-2 and OCO-3 satellite data
State-wide California 2020 carbon dioxide budget estimated with OCO-2 and OCO-3 satellite data Open
Satellite observations are instrumental in observing spatiotemporal variability in carbon dioxide (CO2) concentrations, which can be used to derive fluxes of this greenhouse gas. This study leverages NASA's Orbiting Carbon Observatory-2 an…
View article: Simulating out-of-sample atmospheric transport to enable flux inversions
Simulating out-of-sample atmospheric transport to enable flux inversions Open
Accurately estimating greenhouse gas (GHG) emissions from atmospheric observations requires resolving the upwind influence of measurements via atmospheric transport models. However, the computational demands of full-physics models limit th…
View article: Impacts of Interannual Isoprene Variations on Methane Lifetimes and Trends
Impacts of Interannual Isoprene Variations on Methane Lifetimes and Trends Open
Recent observations show anomalously high methane growth in 2020, which has been attributed to increased wetland emissions and decreased OH from lower COVID‐19 nitrogen oxide (NO x ) emissions. NO x is not the only species that affects OH—…
View article: Emulating chemistry-climate dynamics with a linear inverse model
Emulating chemistry-climate dynamics with a linear inverse model Open
Coupled chemistry–climate models (CCMs) are powerful tools for investigating chemical variability in the climate system, but high computational cost limits their use for hypothesis testing and adequately sampling variability on long timesc…
View article: Differences in Regional Home Heating Behavior in Three U.S. Cities Revealed by Ground‐Based Sensor Network
Differences in Regional Home Heating Behavior in Three U.S. Cities Revealed by Ground‐Based Sensor Network Open
Home heating preferences vary dramatically with regional climate. The temperature at which residents turn on natural gas home heating systems (critical temperature) varies by as much as 25°C from the northern to southern United States (U.S…
View article: High-resolution greenhouse gas flux inversions using a machine learning surrogate model for atmospheric transport
High-resolution greenhouse gas flux inversions using a machine learning surrogate model for atmospheric transport Open
Quantifying greenhouse gas (GHG) emissions is critically important for projecting future climate and assessing the impact of environmental policy. Estimating GHG emissions using atmospheric observations is typically done using source–recep…
View article: Carbon-I, a NASA Earth System Explorer Mission concept for Greenhouse Gas Observations
Carbon-I, a NASA Earth System Explorer Mission concept for Greenhouse Gas Observations Open
The past two decades have seen tremendous improvements in greenhouse gas (GHG) remote sensing from space, including global area flux mappers like SCIAMACHY, GOSAT, OCO-2, GOSAT-2, TROPOMI and OCO-3 among others, with more missions planned,…
View article: Connecting Urban Black Carbon Emissions and Measured Concentrations: A Fusion of Hyperlocal Monitoring and Bayesian Techniques
Connecting Urban Black Carbon Emissions and Measured Concentrations: A Fusion of Hyperlocal Monitoring and Bayesian Techniques Open
Understanding urban air pollution at fine scales is essential for pinpointing emission sources that disproportionately impact vulnerable communities. Traditional emission inventories often suffer from insufficient spatial granularity and l…
View article: FootNet v1.0: development of a machine learning emulator of atmospheric transport
FootNet v1.0: development of a machine learning emulator of atmospheric transport Open
There has been a proliferation of dense observing systems to monitor greenhouse gas (GHG) concentrations over the past decade. Estimating emissions with these observations is often done using an atmospheric transport model to characterize …
View article: Applying Gaussian Process Machine Learning and Modern Probabilistic Programming to Satellite Data to Infer CO<sub>2</sub> Emissions
Applying Gaussian Process Machine Learning and Modern Probabilistic Programming to Satellite Data to Infer CO<sub>2</sub> Emissions Open
Satellite data provides essential insights into the spatiotemporal distribution of CO2 concentrations. However, many atmospheric inverse models fail to adequately incorporate the spatial and temporal correlations inherent in satellite obse…
View article: Challenges and Opportunities Offered by Geostationary Space Observations for Air Quality Research and Emission Monitoring
Challenges and Opportunities Offered by Geostationary Space Observations for Air Quality Research and Emission Monitoring Open
Space-borne remote sensing of atmospheric chemical constituents is crucial for monitoring and better understanding global and regional air quality. Since the 1990s, the continuous development of instruments onboard low-Earth orbiting (LEO)…
View article: Estimating Carbon Dioxide Emissions in Two California Cities Using Bayesian Inversion and Satellite Measurements
Estimating Carbon Dioxide Emissions in Two California Cities Using Bayesian Inversion and Satellite Measurements Open
NASA's Orbiting Carbon Observatories (OCO‐2 and OCO‐3) provide measurements of column‐averaged carbon dioxide concentrations (XCO 2 ) with sufficient spatial resolution and precision to constrain bottom‐up estimates of CO 2 fluxes at regio…
View article: High-resolution greenhouse gas flux inversions using a machine learning surrogate model for atmospheric transport
High-resolution greenhouse gas flux inversions using a machine learning surrogate model for atmospheric transport Open
Quantifying greenhouse gas (GHG) emissions is critically important for projecting future climate and assessing the impact of environmental policy. Estimating GHG emissions using atmospheric observations is typically done using source-recep…
View article: State-wide California 2020 Carbon Dioxide Budget Estimated with OCO-2 and OCO-3 satellite data
State-wide California 2020 Carbon Dioxide Budget Estimated with OCO-2 and OCO-3 satellite data Open
Satellite observations are instrumental in observing spatiotemporal variability in carbon dioxide (CO2) concentrations which can be used to derive fluxes of this greenhouse gas. This study leverages NASA’s Orbiting Carbon Observatory-2 and…
View article: Neighborhood-Level Nitrogen Dioxide Inequalities Contribute to Surface Ozone Variability in Houston, Texas
Neighborhood-Level Nitrogen Dioxide Inequalities Contribute to Surface Ozone Variability in Houston, Texas Open
In Houston, Texas, nitrogen dioxide (NO2) air pollution disproportionately affects Black, Latinx, and Asian communities, and high ozone (O3) days are frequent. There is limited knowledge of how NO2 inequalities vary in urban air quality co…
View article: Integrating Mobile and Fixed-Site Black Carbon Measurements to Bridge Spatiotemporal Gaps in Urban Air Quality
Integrating Mobile and Fixed-Site Black Carbon Measurements to Bridge Spatiotemporal Gaps in Urban Air Quality Open
Urban air pollution can vary sharply in space and time. However, few monitoring strategies can concurrently resolve spatial and temporal variation at fine scales. Here, we present a new measurement-driven spatiotemporal modeling approach t…
View article: Sensitive Response of Atmospheric Oxidative Capacity to the Uncertainty in the Emissions of Nitric Oxide (NO) From Soils in Amazonia
Sensitive Response of Atmospheric Oxidative Capacity to the Uncertainty in the Emissions of Nitric Oxide (NO) From Soils in Amazonia Open
Soils are a major source of nitrogen oxides, which in the atmosphere help govern its oxidative capacity. Thus the response of soil nitric oxide (NO) emissions to forcings such as warming or forest loss has a meaningful impact on global atm…
View article: The Post-2020 Surge in Global Atmospheric Methane Observed in Ground-based Observations
The Post-2020 Surge in Global Atmospheric Methane Observed in Ground-based Observations Open
Methane (CH4) is a potent greenhouse gas with high radiative forcing and a relatively short atmospheric lifetime of around a decade. We used a decade-long dataset (2011-2022) from the Fourier transform spectrometer at the California Labora…
View article: Sustained Reductions of Bay Area CO<sub>2</sub> Emissions 2018–2022
Sustained Reductions of Bay Area CO<sub>2</sub> Emissions 2018–2022 Open
Cities represent a significant and growing portion of global carbon dioxide (CO2) emissions. Quantifying urban emissions and trends over time is needed to evaluate the efficacy of policy targeting emission reductions as well as to understa…
View article: Increased methane emissions from oil and gas following the Soviet Union’s collapse
Increased methane emissions from oil and gas following the Soviet Union’s collapse Open
Global atmospheric methane concentrations rose by 10 to 15 ppb/y in the 1980s before abruptly slowing to 2 to 8 ppb/y in the early 1990s. This period in the 1990s is known as the “methane slowdown” and has been attributed in part to the co…
View article: Towards CO2 emission estimation in urban areas using a dense sensor network and the high-resolution GRAMM/GRAL model
Towards CO2 emission estimation in urban areas using a dense sensor network and the high-resolution GRAMM/GRAL model Open
Urban areas are responsible for about 70% of anthropogenic CO2 emissions and are therefore an important system in which to develop mitigation strategies to reduce emissions. To assess these strategies and monitor mitigation efforts, indepe…
View article: Summer aridity decouples growth from carbon assimilation in temperate oaks
Summer aridity decouples growth from carbon assimilation in temperate oaks Open
Forest biomass resulting from tree radial growth can remain on the landscape over decadal to centennial timescales and plays a critical role in forest carbon cycling. However, visually green vegetation may not be a good proxy for carbon al…
View article: Integrating Mobile and Fixed-Site Black Carbon Measurements to Bridge Spatiotemporal Gaps in Urban Air Quality
Integrating Mobile and Fixed-Site Black Carbon Measurements to Bridge Spatiotemporal Gaps in Urban Air Quality Open
Urban air pollution can vary sharply in space and time. However, few monitoring strategies can concurrently resolve spatial and temporal variation at fine scales. Here, we present a new measurement-driven spatiotemporal modeling approach t…