Skip to main content

ASU Scholarship Showcase


Contributor
Date Range
2013 2017

The INFLUX experiment has taken multiple approaches to estimate the carbon dioxide (CO[subscript 2]) flux in a domain centered on the city of Indianapolis, Indiana. One approach, Hestia, uses a bottom-up technique relying on a mixture of activity data, fuel statistics, direct flux measurement and modeling algorithms. A second uses a Bayesian atmospheric inverse approach constrained by atmospheric CO[subscript 2] measurements and the Hestia emissions estimate as a prior CO[subscript 2] flux. The difference in the central estimate of the two approaches comes to 0.94 MtC (an 18.7% difference) over the eight-month period between September 1, 2012 and April 30, ...

Contributors
Gurney, Kevin, Liang, Jianming, Patarasuk, Risa, et al.
Created Date
2017-08-03

We assess the detectability of city emissions via a tower-based greenhouse gas (GHG) network, as part of the Indianapolis Flux (INFLUX) experiment. By examining afternoon-averaged results from a network of carbon dioxide (CO[subscript 2]), methane (CH[subscript 4]), and carbon monoxide (CO) mole fraction measurements in Indianapolis, Indiana for 2011–2013, we quantify spatial and temporal patterns in urban atmospheric GHG dry mole fractions. The platform for these measurements is twelve communications towers spread across the metropolitan region, ranging in height from 39 to 136 m above ground level, and instrumented with cavity ring-down spectrometers. Nine of the sites were deployed as ...

Contributors
Miles, Natasha L., Richardson, Scott J., Lauvaux, Thomas, et al.
Created Date
2017-06-13

The ‘Hestia Project’ uses a bottom-up approach to quantify fossil fuel CO[subscript 2] (FFCO[subscript 2]) emissions spatially at the building/street level and temporally at the hourly level. Hestia FFCO[subscript 2] emissions are provided in the form of a group of sector-specific vector layers with point, line, and polygon sources to support carbon cycle science and climate policy. Application to carbon cycle science, in particular, requires regular gridded data in order to link surface carbon fluxes to atmospheric transport models. However, the heterogeneity and complexity of FFCO[subscript 2] sources within regular grids is sensitive to spatial resolution. From the perspective of ...

Contributors
Liang, Jianming, Gurney, Kevin, O'Keeffe, Darragh, et al.
Created Date
2017-05-19

Quantifying greenhouse gas (GHG) emissions from cities is a key challenge towards effective emissions management. An inversion analysis from the INdianapolis FLUX experiment (INFLUX) project, as the first of its kind, has achieved a top-down emission estimate for a single city using CO[subscript 2] data collected by the dense tower network deployed across the city. However, city-level emission data, used as a priori emissions, are also a key component in the atmospheric inversion framework. Currently, fine-grained emission inventories (EIs) able to resolve GHG city emissions at high spatial resolution, are only available for few major cities across the globe. Following ...

Contributors
Oda, Tomohiro, Lauvaux, Thomas, Lu, Dengsheng, et al.
Created Date
2017-06-14

The objective of the Indianapolis Flux Experiment (INFLUX) is to develop, evaluate and improve methods for measuring greenhouse gas (GHG) emissions from cities. INFLUX’s scientific objectives are to quantify CO[subscript 2] and CH[subscript 4] emission rates at 1 km[subscript 2] resolution with a 10% or better accuracy and precision, to determine whole-city emissions with similar skill, and to achieve high (weekly or finer) temporal resolution at both spatial resolutions. The experiment employs atmospheric GHG measurements from both towers and aircraft, atmospheric transport observations and models, and activity-based inventory products to quantify urban GHG emissions. Multiple, independent methods for estimating urban ...

Contributors
Davis, Kenneth J., Deng, Aijun, Lauvaux, Thomas, et al.
Created Date
2017-05-23

Megacities are major sources of anthropogenic fossil fuel CO[subscript 2] (FFCO[subscript 2]) emissions. The spatial extents of these large urban systems cover areas of 10 000 km[superscript 2] or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO[subscript 2] emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO[subscript 2] emission product, Hestia-LA, to simulate atmospheric CO[subscript 2] concentrations across the LA megacity at spatial resolutions as fine as ∼ 1 km. We evaluated multiple WRF configurations, selecting one that ...

Contributors
Feng, Sha, Lauvaux, Thomas, Newman, Sally, et al.
Created Date
2016-07-22

Atmospheric radiocarbon ([superscript 14]C) represents an important observational constraint on emissions of fossil-fuel derived carbon into the atmosphere due to the absence of [superscript 14]C in fossil fuel reservoirs. The high sensitivity and precision that accelerator mass spectrometry (AMS) affords in atmospheric [superscript 14]C analysis has greatly increased the potential for using such measurements to evaluate bottom-up emissions inventories of fossil fuel CO[subscript 2] (CO[subscript 2]ff), as well as those for other co-emitted species. Here we use observations of [superscript 14]CO[subscript 2] and a series of primary hydrocarbons and combustion tracers from discrete air samples collected between June 2009 and ...

Contributors
LaFranchi, B. W., Petron, G., Miller, J. B., et al.
Created Date
2013-11-15

Urban environments are the primary contributors to global anthropogenic carbon emissions. Because much of the growth in CO[subscript 2] emissions will originate from cities, there is a need to develop, assess, and improve measurement and modeling strategies for quantifying and monitoring greenhouse gas emissions from large urban centers. In this study the uncertainties in an aircraft-based mass balance approach for quantifying carbon dioxide and methane emissions from an urban environment, focusing on Indianapolis, IN, USA, are described. The relatively level terrain of Indianapolis facilitated the application of mean wind fields in the mass balance approach. We investigate the uncertainties in ...

Contributors
Cambaliza, M. O. L., Shepson, P. B., Caulton, D. R., et al.
Created Date
2014-09-02

We present a high-resolution atmospheric inversion system combining a Lagrangian Particle Dispersion Model (LPDM) and the Weather Research and Forecasting model (WRF), and test the impact of assimilating meteorological observation on transport accuracy. A Four Dimensional Data Assimilation (FDDA) technique continuously assimilates meteorological observations from various observing systems into the transport modeling system, and is coupled to the high resolution CO[subscript 2] emission product Hestia to simulate the atmospheric mole fractions of CO[subscript 2]. For the Indianapolis Flux Experiment (INFLUX) project, we evaluated the impact of assimilating different meteorological observation systems on the linearized adjoint solutions and the CO[subscript 2] ...

Contributors
Deng, Aijun, Lauvaux, Thomas, Davis, Kenneth J., et al.
Created Date
2017-05-23

Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO[subscript 2] mole fractions and Δ[superscript 14]C and δ[superscript 13]C values of CO[subscript 2] in the Los Angeles megacity observed in inland Pasadena (2006–2013) and coastal Palos Verdes peninsula (autumn 2009–2013), we have determined time series for CO[subscript 2] contributions from fossil fuel combustion (C[subscript ff]) for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena C[subscript ff] during the Great Recession of 2008–2010, ...

Contributors
Newman, Sally, Xu, Xiaomei, Gurney, Kevin, et al.
Created Date
2016-03-22