A5060379703- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Vehicle emissions and performance
- Atmospheric and Environmental Gas Dynamics
- Cosmology and Gravitation Theories
- Air Quality Monitoring and Forecasting
- Energy, Environment, and Transportation Policies
- Climate Change Policy and Economics
- Laser-Plasma Interactions and Diagnostics
- Energy and Environment Impacts
- Chemical Synthesis and Analysis
- Relativity and Gravitational Theory
- Geophysics and Gravity Measurements
- Climate Change and Health Impacts
- Aeolian processes and effects
- Particle Dynamics in Fluid Flows
- nanoparticles nucleation surface interactions
- Geological formations and processes
- Supramolecular Self-Assembly in Materials
- Solar and Space Plasma Dynamics
- Hydrocarbon exploration and reservoir analysis
- Coagulation and Flocculation Studies
- Black Holes and Theoretical Physics
Carnegie Mellon University
2016-2025
D. E. Shaw Research
2021
University of Auckland
2016
Goddard Institute for Space Studies
1975-2012
Columbia University
2012
Los Alamos National Laboratory
1987-2011
Radboud University Nijmegen
1986-2007
California Institute of Technology
1985-2003
Carleton University
1996-1998
Garvan Institute of Medical Research
1992
<strong class="journal-contentHeaderColor">Abstract.</strong> This paper evaluates the current status of global modeling organic aerosol (OA) in troposphere and analyzes differences between models as well observations. Thirty-one chemistry transport (CTMs) general circulation (GCMs) have participated this intercomparison, framework AeroCom phase II. The simulation OA varies greatly terms magnitude primary emissions, secondary (SOA) formation, number species used (2 to 62), complexity...
To better represent the indirect effect of aerosols on climate, a size‐resolved simulation aerosol microphysics, size distributions, number and mass concentrations has been incorporated into GISS general circulation model (GCM). The TwO‐Moment Aerosol Sectional (TOMAS) microphysics used here conserves as well mass. It high resolution, 30 bins between 0.01 10 μm diameter. As first application, sulfate performed. reproduces important features atmospheric such that increase with altitude...
Abstract. The indirect effect of aerosols on climate is highly uncertain and limits our ability to assess anthropogenic change. foundation this uncertainty in the number cloud condensation nuclei (CCN), which itself stems from aerosol nucleation, primary emission growth rates. In paper, we use a global general circulation model with microphysics how uncertainties rates affect prediction CCN(0.2%) concentrations. Using several nucleation rate parameterizations that span six orders magnitude...
Abstract. The individual effects of various meteorological parameters on PM2.5 concentrations in the Eastern US are examined using PMCAMx chemical transport model so that these and their relative magnitudes can be better understood. A suite perturbations temperature, wind speed, absolute humidity, mixing height, cloud cover, precipitation imposed individually base case conditions corresponding to periods July 2001 January 2002 order determine sensitivities composition separate parameters....
Significance Secondary organic aerosol (SOA) formed from the atmospheric oxidation of gaseous combustion emissions is an important component global fine-particle pollution, which influences Earth’s energy budget and affects human health. However, existing models underpredict amount SOA measured in laboratory experiments atmosphere. We analyze smog chamber data to demonstrate that unspeciated organics are a major class precursors. develop source-specific parameterizations for these using...
Abstract We present global direct radiative effect (DRE) calculations of carbonaceous aerosols emitted from biomass/biofuel burning addressing the interplay between two poorly constrained contributions to DRE: mixing state black carbon (lensing) and light absorption by organic aerosol (OA) due presence brown (BrC). use parameterization Saleh et al. (2014) which captures variability in OA absorption. The mean is +0.22 W/m 2 +0.12 for externally internally mixed cases, while lensing +0.39...
Significance Poor air quality is the largest environmental health risk in United States and worldwide, agriculture a major source of pollution. Nevertheless, has been largely absent from discussions about impacts food. We estimate quality–related States, finding that 80% 15,900 annual deaths result food-related fine particulate matter (PM 2.5 ) pollution are attributable to animal-based foods. By estimating these exploring how reduce them, this work fills critical knowledge gap. Our results...
Global sulfate aerosol composition is simulated online in the Goddard Institute for Space Studies general circulation model II′ (GISS GCM II‐prime). Four sulfur species, hydrogen peroxide, gas phase ammonia, and particulate ammonium are prognostic tracer emissions, transport, deposition of which explicitly simulated. Nitric acid fields prescribed based on a global chemical transport model. An thermodynamic equilibrium calculation determines partitioning ammonia nitrate between phases,...
Current regulation aimed at reducing inorganic atmospheric fine particulate matter (PM2.5) is focused on reductions in sulfur dioxide (SO2) and oxides of nitrogen (NOx ≡ NO + NO2); however, controls these pollutants are likely to increase cost decrease effectiveness the future. A supplementary strategy reduction ammonia (NH3) emissions, yet an evaluation has been limited by uncertainties emission levels control technologies. We use state science inventories, emission-based regional air...
The contribution of both the sea‐salt emissions and specifically ultrafine (dry D p < 0.1 μm) component these to global CCN was assessed with a model aerosol microphysics. Four parameterizations were incorporated into GISS II‐prime general circulation size‐resolved microphysics module, TOMAS. results four simulations compared observations monthly average PM 10 mass, mass size distributions, marine number distributions. agreement varied greatly based on parameterization used, but...
An on‐line simulation of aerosol sulfate, nitrate, ammonium, and water in the Goddard Institute for Space Studies general circulation model (GCM II‐prime) has been used to estimate direct radiative forcing years 1800, 2000, 2100. This is first based on equilibrium content a changing SO 4 2− ‐NO 3 − ‐NH + mixture nitrate global aerosol. Present‐day annual average anthropogenic estimated be −0.95 −0.19 W/m 2 sulfate respectively. Simulations with future emissions scenario indicate that could...
Abstract. Atmospheric cloud condensation nuclei (CCN) concentrations are a key uncertainty in the assessment of effect anthropogenic aerosol on clouds and climate. The ability new ultrafine particles to grow become CCN varies throughout atmosphere must be understood order understand formation. We have developed Probability Ultrafine particle Growth (PUG) model answer questions regarding which growth sink mechanisms control this growth, how between different parts uncertainties with respect...
By associating the mathematical operation of scale transformation with physics using different dynamical systems to measure space-time distances, we formulate a scale-covariant theory gravitation. Corresponding each system units is gauge condition which determines otherwise arbitrary function. For gravitational units, chosen so that standard Einstein equations are recovered. Assuming atomic derivable from dynamics, be distinct must imposed. It suggested Dirac's large-number hypothesis used...
This paper provides a synthesis of results that have emerged from recent modeling studies the potential sensitivity U.S. regional ozone (O3) concentrations to global climate change (ca. 2050). research has been carried out under auspices an ongoing Environmental Protection Agency (EPA) assessment effort increase scientific understanding multiple complex interactions among climate, emissions, atmospheric chemistry, and air quality. The ultimate goal is enhance ability quality managers...
Global simulations of sea salt and mineral dust aerosols are integrated into a previously developed unified general circulation model (GCM), the Goddard Institute for Space Studies (GISS) GCM II′, that simulates coupled tropospheric ozone‐NO x ‐hydrocarbon chemistry sulfate, nitrate, ammonium, black carbon, primary organic secondary carbon aerosols. The fully gas‐aerosol allows one to evaluate extent which global burdens, radiative forcing, eventually climate feedbacks ozone influenced by...
A unified tropospheric chemistry‐aerosol model has been developed within the Goddard Institute for Space Studies general circulation (GCM). The includes a detailed simulation of ozone‐NO x ‐hydrocarbon chemistry as well aerosols and aerosol precursors. Predicted species include sulfate, nitrate, ammonium, black carbon, primary organic secondary carbon. partitioning ammonia nitrate between gas phases is determined by on‐line thermodynamic equilibrium, formation based on equilibrium...
An integrated global model of climate, tropospheric gas phase chemistry, and aerosols has been used to investigate the sensitivity ozone fine particulate matter concentrations climate change. Two simulations corresponding present (1990s) future (2050s) climates have performed compared. A imposed using ocean boundary conditions Intergovernmental Panel on Climate Change SRES A2 scenario for 2050s decade, resulting in an increase annual average values surface air temperature by 1.7°C, lower...
Abstract. Many of the next generation global climate models will include aerosol schemes which explicitly simulate microphysical processes that determine particle size distribution. These enable optical properties and cloud condensation nuclei (CCN) concentrations to be determined by fundamental processes, should lead a more physically based simulation direct indirect radiative forcings. This study examines variation in distribution simulated 12 microphysics quantify model diversity identify...
The volatility basis set, a computationally efficient framework for the description of organic aerosol partitioning and chemical aging, is implemented in Goddard Institute Space Studies General Circulation Model II′ coupled global circulation transport model to simulate secondary (SOA) formation. latest smog chamber information about yields anthropogenic biogenic precursors incorporated model. SOA formation from monoterpenes, sesquiterpenes, isoprene, estimated as 17.2, 3.9, 6.5, 1.6 Tg yr...
Abstract. We calculate decadal aerosol direct and indirect (warm cloud) radiative forcings from US anthropogenic sources over the 1950–2050 period. Past future distributions are constructed using GEOS-Chem historical emission inventories projections IPCC A1B scenario. Aerosol simulations evaluated with observed spatial 1980–2010 trends of concentrations wet deposition in contiguous US. Direct forcing is calculated GISS general circulation model monthly mean GEOS-Chem. The aerosols strongly...
Abstract. We investigate the climate response to changing US anthropogenic aerosol sources over 1950–2050 period by using NASA GISS general circulation model (GCM) and comparing observed temperature trends. Time-dependent distributions are generated from GEOS-Chem chemical transport applied historical emission inventories future projections. Radiative forcing aerosols peaked in 1970–1990 has strongly declined since due air quality regulations. find that regional radiative elicits a strong...
Although controversial, many observations have suggested that low‐level cloud cover correlates with the cosmic ray flux. Because galactic rays likely decreased in intensity over last century, this hypothesis, if true, could partly explain 20th century warming, thereby upsetting consensus view greenhouse‐gas forcing has caused most of warming. The “ion‐aerosol clear‐air” hypothesis suggests increased cause increases new‐particle formation, condensation nuclei concentrations (CCN), and cover....
Air quality in the United States has dramatically improved, yet exposure to air pollution is still associated with 100000–200000 deaths annually. Reducing number of effectively, efficiently, and equitably relies on attributing them specific emission sources, but so far, this been done for only highly aggregated groups or a select few sources interest. Here, we estimate mortality attributable all domestic, human-caused emissions primary PM2.5 secondary precursors. We present detailed...
The Marcellus Shale is one of the largest natural gas reserves in United States; it has recently been focus intense drilling and leasing activity. This paper describes an air emissions inventory for development, production, processing region 2009 2020. It includes estimates oxides nitrogen (NOx), volatile organic compounds (VOCs), primary fine particulate matter (≤2.5 µm aerodynamic diameter; PM2.5) from major activities such as drilling, hydraulic fracturing, compressor stations, completion...