Current research projects

Jump to detailed descriptions of each project by following the links below:

Improved decision support tools through inverse modeling and sensitivity analysis

  • Background

    Concentrations of fine particulate matter (PM2.5) presently pose a serious health hazard to tens of millions of people in the U.S. While a significant portion of this PM2.5 is governed by the gas-phase precursors NH3 and NOx, current efforts to ascertain and control the influence of NH3 and NOx on air quality are hindered by large uncertainties in emissions inventories and compounded by complexities of the chemical and physical processes by which these species ultimately form PM2.5.

  • Objectives

    The overarching objective of this proposal is to utilize Earth science products for improved air quality management at the U.S. Environmental Protection Agency (EPA). The specific goals are:
    • to support upcoming updates to the EPA's National Emissions Inventory utilizing observations of NO2 from remote sensing instruments (OMI, SCIAMACHY) with speciated PM2.5 measurements from surface air quality monitoring networks.
    • to support Regulatory Impact Analysis (RIA) by estimating how regulating specific sources of PM2.5 precursors can most effectively reduce NAAQS nonattainment, considering both present day and mid-century climate.

  • People

    Matt Turner, Havala Pye (now at US EPA)

  • Collaborators

    Patrick Kinney (Columbia University), Ying Li (Columbia University), Darby Jack (Columbia University), Robert Pinder (US EPA), Sergey Napelenok (US EPA), Loretta Mickley (Harvard), Randall Martin (Dalhousie), Bryan Hubbell (US EPA), Amir Hakami (Carleton University)

  • Support

    NASA Applied Sciences
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Constraining NH3 distributions through remote sensing, modeling, and surface observations

  • Background

    Ammonia (NH3) affects air quality and climate through its role in the mass, composition and physical properties of tropospheric aerosol. The detection of boundary layer ammonia by the NASA TES instrument provides unprecedented opportunity for reducing persistent uncertainties in our understanding of the distribution and impacts of atmospheric ammonia. In order to maximize the potential of TES observations to constrain model estimates of these important processes, we will take advantage of recently developed data assimilation tools and targeted in situ measurements of surface-level NH3 concentrations.

  • Objectives

    • Provide observational constraints on the magnitude of NH3 sources and atmospheric NHx distributions first in a local case study in North Carolina and then throughout the Continental U.S.
    • quantify the magnitude and variability, both geographical and seasonal, of U.S. NH3 emissions at a high spatial resolution
    • provide detailed estimates of PM2.5 control efficiencies and how they will evolve owing to regulations that alter key balances among inorganic particulate species
    • Reduce uncertainty in the effective atmospheric lifetime of NH3 by constraining bi-directional NH3 flux from agricultural vs natural land types.
    • Improve both spatial distribution and seasonal estimates of sources and fates of NHx in global models

  • People

    Juliet Zhu, Gill-Ran Jeong

  • Collaborators

    Robert Pinder (US EPA), Jesse Bash (US EPA), John Walker (US EPA), Karen Cady-Pereira (AER), Mingzhao Luo (NASA JPL), Mark Shephard (Environment Canada)

  • Findings

    The following shows the NH3 concentrations observed from the TES satellite over a period of several years for the month of January. The color and height indicate the strength of the measured signal in terms of a representative volume mixing ratio, which is an average of the observed profile over the altitude range for which the instrument was sensitive. The number of sides of each column indicates the representative altitude (fewer sides indicate an observation closer to the surface). Transparency represents the data quality in terms of DOFs. The utility of mapping the data on Google Earth is visually exploring possible sources of NH3, which largely comes from agricultural activity. A nice example is in SW Kansas -- if you zoom in on the light blue peak, you can see a large cattle feed lot and even individual cows below.

  • Support

    NASA ACMAP, EPA-STAR Early Career Award
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Accounting for Costs of Air Quality and Climate Impacts on the Future US Electricity Mix

  • Background

    Electricity production in the US is influenced by many factors, but some aspects of electricity generation are not considered in the choice of electricity. The emission of pollutants from electricity generating plants affects both the local air quality and the global climate, but neither are reflected in the price of electricity.

  • Objectives

    This project aims to determine how implementing emissions fees based on damages would impact the mix of electricity in the US. Damages from criteria pollutants (NOx, SO2, and particulate mater, PM) as well as greenhouse gases (GHGs) are considered in determining fees.

  • People

    Kristen Brown

  • Collaborators

    Jana Milford (CU Boulder), Garvin Heath (NREL), Nicholas Flores (CU Boulder)

  • Support

    The Renewable and Sustainable Energy Institute (RASEI)
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Source attribution of aerosol and ozone radiative forcing

  • Background

    Tropospheric ozone (O3) and fine-mode aerosols significantly impact climate through their direct radiative effects. Unlike carbon dioxide, the relationship between emissions of O3 and aerosol precursors and the ultimate consequence of these emissions on climate is highly variable, depending on the local chemical and physical environment. Anticipating climate change in the coming decades thus requires relating heterogenous, uncertain changes to global arrays of emission of O3 and aerosol precursors to changes in atmospheric composition and hence radiative forcing.

  • Objectives

    • The sensitivity of direct radiative effects of fine-mode aerosol and O3 with respect to concentration distributions will be quantified using information gleaned from satellite data.
    • The direct radiative forcing of aerosols will be attributed to specific emissions of SO2, black carbon and organic carbon.

  • People

    Forrest Lacey

  • Collaborators

    Kevin Bowman (NASA JPL), Adetutu Aghedo (NASA JPL), Helen Worden (NCAR), Robert Pinder (US EPA)

  • Support

    NASA New Investigator Program, CU Discovery Learning Apprenticeship
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Sources of nitrate in Antarctica

  • Background

    The formation and cycling of reactive nitrogen in the atmosphere has important implications for air quality, the oxidation capacity of the atmosphere, and atmospheric nutrient deposition. The importance of different sources of nitrate to Antarctica remains an open question. NOx is emitted to the atmosphere from primarily continental sources - combustion (fossil fuel, biomass, biofuel), soil exhalation, and lightning. Due to the remoteness of Antarctica from continents, it has been difficult to attribute Antarctic nitrate to specific sources. This is compounded by the fact that nitrate is redistributed across the Antarctic continent due to postdepositional processing of snowpack nitrate.

  • Objectives

    Estimate the importance of difference sources of nitrate to Antarctica

  • People

    Hyungmin Lee

  • Collaborators

    Becky Alexander (PI, University of Washington)

  • Support

    NSF Office of Polar Programs
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GLIMPSE: Accounting for short lived climate forcers in air quality policy

  • Background

    A key climate mitigation question is "what is the impact of US emission control strategies on global climate?" Scientifically credible assessments require an ensemble of multi-century simulations using global climate models. The computational expense of such simulations makes this feasible only for a few, representative scenarios. Decision-makers need approximation tools that can be used to rapidly screen the costs and benefits of climate mitigation strategies. For long-lived green house gases, the emissions are proportional to the climate impacts. However, short-lived radiatively active gases and aerosols undergo chemical and physical transformations that substantially change their climate impacts.

  • Objectives

    • Improvements to the US EPA 9-region MARKAL database
    • Incorporate radiative forcing impacts into the MARKAL tool to examine (and constrain) the response of US energy and technology scenarios
    More information at the GLIMPSE and EPA web sites.

  • Collaborators

    Robert Pinder, Farhan Akhtar, and Dan Loughlin (US EPA); Robert Spurr (RT Solutions)

  • Findings

    Example pic

    Fig: Direct radiative forcing from aerosol precursor emissions were applied to several different technology / emissions scenarios.



  • Support

    US EPA STAR, NASA New Investigator Program, NASA AQAST
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Glory: constraining aerosol sources and radiative forcing

  • Background

    The APS instrument aboard the Glory satellite was to provide unprecedented remote sensing capabilities for constraining our understanding of global aerosol distributions, and thus helping reduce uncertainty in a key area of climate and air quality modeling. By measuring the polarization of backscattered radiation, this instrument would have been able to provide independent constraints on aerosol composition and optical properties. Unfortunately, the launch of this satellite into space was unsuccessful. Nevertheless, our project working in this area of research continues. Read more.

  • Objectives

    • Characterize potential radiative forcing and source constraints from photopolarimetric measurements
    • Multi-sensor constraints on aerosol sources and radiative forcing

  • People

    Brian Meland

  • Collaborators

    Jun Wang (University of Nebraska)

  • Support

    NASA Glory Science Team
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Constraining BC distributions, sources, regional climate impacts, and co-benefit metrics

  • Background

    Black carbonaceous aerosol (BC) is an important component of atmospheric particulate matter because of its dual roles in health and climate. BC contributes significantly to surface mass concentrations of fine particulate matter (PM2.5), exposure to which is linked to increased mortality and pulmonary disease (e.g., Pope et al., 2002; Schwartz et al., 2008). In addition, BC is a strong short-lived climate forcing agent (SLCFA). Through its direct absorption of incoming shortwave radiation, BC is estimated from models and observations to have a global direct radiative forcing within the range of 0.2 to 1.2 W/m2 (Forster 2007; Ramanathan and Carmichael, 2008). Its efficacy as a climate forcer is also very high when deposited on snow (Hansen and Nazarenko, 2004; Hansen et al., 2005; Flanner et al., 2007). These aspects combined have made BC a target for mitigation efforts with health and climate co-benefits (e.g., Jacobson, 2001; Bond, 2004; Unger et al., 2010). Yet, the potential impact of BC emissions reductions on climate may be counteracted by indirect effects of BC on clouds and the degree to which the potential for co-benefits is modulated by co-emission of BC with reflective, cooling, aerosol (Aunan, 2009; Bauer et al., 2010; Chen et al., 2010; Ramana et al., 2010).

  • Objectives

    • Rank and constrain the contributions of transport, deposition, aerosol properties, and emissions to uncertainty in estimates of BC distributions in urban and remote areas and of BC radiative forcing.
    • Improve model representation of BC distributions at urban to regional scales through assimilation of surface, aircraft and remote sensing measurements for use in estimating air quality and climate impacts.
    • Assess the range of BC uncertainties in climate impacts metrics, and develop novel metrics for air quality and climate impacts that reflect the competing effects of co-pollutants and account for propagation of uncertainties in source, transport, and radiative processes.

  • People

    JJ Guerrette, Li Zhang

  • Collaborators

    Greg Carmichael (PI, University of Iowa), Scott Spak (University of Iowa), Georg Grell (NOAA)

  • Support

    EPA-STAR
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NASA Air Quality Applied Sciences Team

  • Overview

    The NASA Air Quality Applied Sciences Team (AQAST) strives to optimize the value of Earth Science satellites, suborbital platforms, and models to serve the needs of air quality management. An overview of the entire team is here.

  • People

    Kateryna Lapina

  • Collaborators

    List of AQAST members.

  • Support

    NASA Applied Sciences
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Satellite-based inverse modeling of CO2 fluxes

  • Background

    Accurate and precise estimates of regional sources and sinks of CO2 are necessary for developing effective carbon management strategies and reliable projection of future atmospheric abundances of CO2. "Top-down" estimates of carbon flux from atmospheric CO2 measurements play a critical role in placing constraints on the carbon budget partitioned between anthropogenic, oceanic, and biospheric processes. The uncertainties in these flux estimates can be large, ranging from -1 to 2 PgC/yr in the tropics for example, as a consequence of inadequate observational coverage and representation of atmospheric transport relating observations to surface emissions [IPCC, 2007]. Transport error has been identified as a significant source of uncertainty in top-down carbon flux estimates [e.g., Baker et al., 2006a, Stevens et al., 2007]. The global coverage provided by space-based measurements complements the surface networks and has the potential to greatly improve the accuracy and precision of regionally-resolved flux estimates provided that the observations have sufficient information content and that transport uncertainties can be addressed [e.g. Pak and Prather, 2001; Rayner and O'Brien, 2001; Houweling et al., 2004; Baker et al., 2006b; Chevallier et al. 2007; Miller et al., 2007; Feng et al., 2009].

  • Objectives

    • Produce regionally-resolved global CO2 fluxes based on a 4Dvar approach constrained by surface measurements and satellite observations of CO2 and CO from TES, GOSAT, and MOPITT.
    • Characterize the uncertainty and spatial resolution of the high-resolution flux estimates.
    • Assess the information content and quality of these satellite datasets.

  • People

    Nicolas Bousserez

  • Collaborators

    Dylan Jones (PI, University of Toronto), Kevin Bowman (PI, NASA JPL)

  • Support

    NASA ACOS, NASA JPL, NASA Carbon Monitoring System
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CMAQ Adjoint

  • Overview

    The Community Multiscale Air Quality (CMAQ) modeling system is utilized by the US EPA to develop emission control regulations for air quality improvements and by research groups around the world to investigate air pollution. Still, air quality models contain uncertainty which drive a continual process of model refinement. Developing a constraint on emissions using 4D-Variational data assimilation is a valuable method for reducing such uncertainty. Towards this gaol,a large consortium of researchers are working together to build a complete 4D-Var system for CMAQ. The original CMAQ adjoint mode was developed for CMAQ 4.5.1 and was limited to gas-phase processes. The current effort includes the addition of aerosol dynamics and thermodynamics, cloud processes, and heterogenous chemistry. The model will also include parallelization, 4D-Variational capabilities, improved modularity, etc. Once the adjoint has been completely implemented and validated, the model will be publicly released.

  • People

    Matt Turner

  • Collaborators

    Hakami, A.; Zhao, S.; Resler, J.; Carmichael, G.; Stanier, C.; Baek, J.; Saide, P.; Sandu, A.; Russel, A.; Jeong, G.; Nenes, A.; Capps, S.; Percell, P.; Pinder, R.; Napelenok, S.; Pye, H.; Bash, J.; Chai, T.

  • Support

    NASA, EPA, API
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Sustainable Energy Pathways

  • Overview

    Energy storage materials play a crucial role for finding a sustainable solution to transportation via electric vehicles. Today's approaches for developing such materials do not take account of the complex tradeoffs between various performance criteria, currently used to design batteries, and sustainability goals, including life cycle costs and economic factors. Our main objective is to create a new paradigm for the design of energy storage materials that bridges the gap between materials research and consideration of the environmental and economic impact of technologies in which these materials will play a crucial role. The proposed research will specifically focus on solid state lithium pyrite (SS-LP) batteries, a new battery material system with extraordinary properties. Scalable processes for fabricating SS-LP will be explored and for the first time their electrochemical reactions will be carefully studied in terms of thermodynamic and kinetics characteristics through modeling and experiments. The multi-scale battery model will be integrated into a multi-objective optimization framework for systematically designing battery electrodes and cell architectures to meet specific performance goals that are defined through environmental and economic trade-off studies.

  • People

    Azadeh Keshavarzmohammadian

  • Collaborators

    Seehe Lee (PI), Jana Milford, Conrad Stoldt, Kurt Maute, Nathalie Moyen, Stephen Lawrence

  • Support

    NSF
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