A5027270746- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Climate variability and models
- Vehicle emissions and performance
- Meteorological Phenomena and Simulations
- Climate Change and Health Impacts
- Fire effects on ecosystems
- Mercury impact and mitigation studies
- Toxic Organic Pollutants Impact
- Wind and Air Flow Studies
- Geophysics and Gravity Measurements
- Species Distribution and Climate Change
- Geology and Paleoclimatology Research
- Global Health Care Issues
- Agriculture, Soil, Plant Science
- Arctic and Antarctic ice dynamics
- Marine and coastal ecosystems
- Ionosphere and magnetosphere dynamics
- Tropical and Extratropical Cyclones Research
- Energy and Environmental Systems
- Ammonia Synthesis and Nitrogen Reduction
Seoul National University
2016-2025
Colorado School of Mines
2020
Chonbuk National University Hospital
2013
NOAA Geophysical Fluid Dynamics Laboratory
2009
Goddard Space Flight Center
2009
Joint Research Centre
2009
University of North Carolina at Chapel Hill
2009
Harvard University
2003-2009
Planetary Science Institute
2003-2008
University of Maryland, College Park
2004
We use a global three‐dimensional coupled oxidant‐aerosol model (GEOS‐CHEM) to estimate natural and transboundary pollution influences on sulfate‐nitrate‐ammonium aerosol concentrations in the United States. This work is motivated part by Regional Haze Rule of U.S. Environmental Protection Agency (EPA), which requires immediate action improve visibility wilderness areas along linear trajectory toward an endpoint “natural conditions” 2064. present full‐year simulations for 1998 2001 evaluate...
Aircraft measurements of organic carbon (OC) aerosol by two independent methods over the NW Pacific during ACE‐Asia campaign reveal unexpectedly high concentrations in free troposphere (FT). Concentrations average 4 μg sm −3 2–6.5 km column with little vertical gradient. These values are 10–100 times higher than computed a global chemical transport model (CTM) including standard 2‐product simulation secondary (SOA) formation based on empirical fits to smog chamber data. The same CTM...
We use a global three‐dimensional model (GEOS‐CHEM) to better quantify the sources of elemental carbon (EC) and organic (OC) aerosols in United States through simulation year‐round observations for 1998 at network 45 sites (Interagency Monitoring Protected Visual Environments (IMPROVE)). Simulation with our best priori understanding sources, including satellite data constrain fire emissions, captures most variance (R 2 = 0.84 EC, 0.67 OC) low bias 15% EC 26% OC. Multiple linear regression...
Understanding the surface O 3 response over a “receptor” region to emission changes foreign “source” is key evaluating potential gains from an international approach abate ozone (O ) pollution. We apply ensemble of 21 global and hemispheric chemical transport models estimate spatial average east Asia (EA), Europe (EU), North America (NA), south (SA) 20% decreases in anthropogenic emissions precursors, NO x , NMVOC, CO (individually combined), each these regions. find that mean concentrations...
We assess the relationship of ground‐level fine particulate matter (PM 2.5 ) concentrations for 2000–2001 measured as part Canadian National Air Pollution Surveillance (NAPS) network and U.S. Quality System (AQS), versus remote‐sensed PM determined from aerosol optical depths (AOD) by Moderate Resolution Imaging Spectroradiometer (MODIS) Multiangle (MISR) satellite instruments. A global chemical transport model (GEOS‐CHEM) is used to simulate factors affecting relation between AOD . AERONET...
We use a global 3‐D model of atmospheric mercury (GEOS‐Chem) to interpret worldwide observations total gaseous (TGM) and reactive (RGM) in terms the constraints they provide on chemical cycling deposition mercury. Our simulation including source 7000 Mg yr −1 TGM lifetime 0.8 years reproduces magnitude large‐scale variability at land sites. However, it cannot capture high from ship cruises, implying problem either measurements or our fundamental understanding sources. Observed seasonal...
We use observations of the mass‐independent oxygen isotopic composition (Δ 17 O) sulfate in marine boundary layer (MBL) to quantify source from aqueous SO 2 (S(IV)) oxidation by O 3 alkaline sea‐salt aerosols. Oxidation imparts a large Δ signature resulting (8.8‰) relative H (0.9‰) or OH (0‰). Ship data two Indian Ocean Experiment (INDOEX) cruises indicate values usually <1‰ submicron aerosol but considerable variability supermicron with frequent occurrences above 1‰ and up 6.7‰. The are...
Abstract. Recent laboratory studies suggest that secondary organic aerosol (SOA) formation rates are higher than assumed in current models. There is also evidence SOA removal by dry and wet deposition occurs more efficiently some models photolysis heterogeneous oxidation may be important (but currently ignored) sinks. Here, we have updated the global GEOS-Chem model to include this new information on (i.e., wall-corrected yields emissions of semi-volatile intermediate volatility compounds)...
The Geostationary Environment Monitoring Spectrometer (GEMS) is scheduled for launch in February 2020 to monitor air quality (AQ) at an unprecedented spatial and temporal resolution from a geostationary Earth orbit (GEO) the first time. With development of UV–visible spectrometers sub-nm spectral sophisticated retrieval algorithms, estimates column amounts atmospheric pollutants (O3, NO2, SO2, HCHO, CHOCHO, aerosols) can be obtained. To date, all satellite missions monitoring have been low...
We use observations of the oxygen‐17 excess (Δ 17 O) sulfate in Arctic to quantify source from aqueous SO 2 (S(IV)) oxidation by O catalyzed transition metals. Due lack photochemically produced OH and H high latitudes during winter, combined with anthropogenic emissions Northern Hemisphere, 3 is predicted dominate formation winter this region. However, Δ measurements aerosol collected Alert, Canada, are not consistent as dominant oxidant indicate that a S(IV) near‐zero values (O ) important...
The “online” meteorological and chemical transport Weather Research Forecasting/Chemistry (WRF/Chem) model has been implemented over a European domain, run without aerosol‐cloud feedbacks for the year 2007, validated against ground‐based observations. To this end, we integrated Monitoring Evaluation Programme (EMEP) anthropogenic emission inventory into pre‐processor. simulated average temperature shows very small negative bias, relative humidity wind speed are overpredicted by 1.5% (8%) 1.0...
Abstract. Recent observations suggest that a certain fraction of organic carbon (OC) aerosol effectively absorbs solar radiation, which is also known as brown (BrC) aerosol. Despite much observational evidence its presence, very few global modelling studies have been conducted because poor understanding BrC emissions. Here we present an explicit simulation in 3-D chemical transport model (GEOS-Chem), including emission estimates from primary (3.9 ± 1.7 and 3.0 1.3 TgC yr−1 biomass burning...
In an environment with many local, remote, persistent, and episodic sources of pollution, meteorology is the primary factor that drives periods unhealthy air quality reduced visibility. The 2016 Korea-United States Air Quality (KORUS-AQ) field study provides a unique opportunity to examine impact on relative influence local transboundary pollution. Much KORUS-AQ campaign can be grouped into four distinct research based observed synoptic meteorology, including period complex aerosol vertical...
The Korea-United States Air Quality (KORUS-AQ) field study was conducted during May–June 2016 to understand the factors controlling air quality in South Korea. Extensive aircraft and ground network observations from campaign offer an opportunity address issues current models reduce model-observation disagreements. This examines these using model evaluation against KORUS-AQ intercomparisons between models. Six regional two global chemistry transport identical anthropogenic emissions...
We present a simple approach to estimating ground‐level fine particulate matter (PM 2.5 , particles smaller than μm in diameter) concentrations by applying local scaling factors from global atmospheric chemistry model (GEOS‐CHEM with GOCART dust and sea salt data) aerosol optical thickness (AOT) retrieved the Multiangle Imaging Spectroradiometer (MISR). The resulting MISR PM are compared measurements U.S. Environmental Protection Agency's (EPA) compliance network for year 2001. Regression...
A global 3‐D chemical transport model is used to analyze observations of carbon monoxide (CO) and upper tropospheric clouds from the EOS Microwave Limb Sounder (MLS). MLS during 25 August–6 September 2004 reveal elevated CO dense high in troposphere over Tibetan plateau southwest China, collocating with level anticyclone. Model simulations indicate boundary layer pollution by Asian summer monsoon (ASM) convection orographic lifting South Asia, where simulated distributions resemble...
We use aircraft observations of Asian outflow from the NASA Transport and Chemical Evolution over Pacific (TRACE‐P) mission NW in March–April 2001 to estimate export efficiency black carbon (BC) aerosol during lifting free troposphere, as limited by scavenging wet processes (warm conveyor belts convection) associated with this lifting. Our is based on enhancement ratio BC relative CO observed at different altitudes normalized boundary layer (0–1 km). similarly efficiencies sulfur oxides (SO...
We present results from a new global atmospheric mercury model coupled with mixed layer slab ocean. The ocean describes the interactions of atmosphere and deep ocean, as well conversion between elemental, divalent, nonreactive species. Our mean aqueous concentrations 0.07 pM 0.80 reactive, 1.51 total agree observations. provides 14.1 Mmol yr −1 source to atmosphere, at upper end previous estimates. Re‐emission previously deposited constitutes 89% this flux. Ocean emissions are largest in...
We use satellite (MODIS) observations of aerosol optical depths (AODs) over the North Pacific, together with surface measurements at a network remote U.S. sites (IMPROVE), to improve understanding transpacific transport Asian pollution and assess ability global 3‐D chemical model (GEOS‐Chem CTM) quantify enhancements in air. The MODIS show strongest occurring spring 40–55°N. This takes place mainly lower free troposphere (900–700 hPa) because scavenging during either boundary layer or...
We examine the ozone production efficiency in transpacific Asian pollution plumes, and implications for air quality California, by using aircraft surface observations April–May 2002 from Intercontinental Transport Chemical Transformation (ITCT 2K2) campaign off California coast Pacific Exploration of Continental Emission–B (PEACE‐B) over northwest Pacific. The are interpreted with a global three‐dimensional chemical transport model (GEOS‐CHEM). reproduces mean features observed CO, reactive...
Abstract. The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium mass. An thermodynamics called twice, once for the upper side (US) lower (LS) hysteresis loop particle phase. On LS, sulfate mass budget 40% solid 12% letovicite, 11% bisulfate, 37% aqueous. LS nitrate 26% 7% aqueous, 67% gas-phase nitric acid release due...