Si‐Wan Kim

Nitrogen oxide (NO x ) emissions resulting from fossil fuel combustion lead to unhealthy levels of near‐surface ozone (O 3 ). One of the largest U.S. sources, electric power generation, represented about 25% of the U.S. anthropogenic NO x emissions in 1999. Here we show that space‐based instruments observed declining regional NO x levels between 1999 and 2005 in response to the recent implementation of pollution controls by utility companies in the eastern U.S. Satellite‐retrieved summertime nit

There are many isolated sources of NO x emissions across the western United States, including electrical power generation plants and urban areas. In this manuscript, two satellite instruments measuring NO 2 vertical columns over these sources and an atmospheric chemical‐transport model are used to evaluate bottom‐up NO x emission inventories, model assumptions, and satellite retrieval algorithms. We carried out simulations with the Weather Research and Forecasting‐Chemistry (WRF‐Chem) model for

Abstract. We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May–June 2010. The US EPA National Emission Inventory 2005 (NEI 2005) was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was use

Abstract. Satellite and aircraft observations made during the 2006 Texas Air Quality Study (TexAQS) detected strong urban, industrial and power plant plumes in Texas. We simulated these plumes using the Weather Research and Forecasting-Chemistry (WRF-Chem) model with input from the US EPA's 2005 National Emission Inventory (NEI-2005), in order to evaluate emissions of nitrogen oxides (NOx = NO + NO2) and volatile organic compounds (VOCs) in the cities of Houston and Dallas-Fort Worth. We compare

Abstract We developed a new nitrogen oxide (NO x ) and carbon monoxide (CO) emission inventory for the Los Angeles‐South Coast Air Basin (SoCAB) expanding the Fuel‐based Inventory for motor‐Vehicle Emissions and applied it in regional chemical transport modeling focused on the California Nexus of Air Quality and Climate Change (CalNex) 2010 field campaign. The weekday NO x emission over the SoCAB in 2010 is 620 t d −1 , while the weekend emission is 410 t d −1 . The NO x emission decrease on wee

Abstract Ozone in the urban atmosphere can accumulate from photochemistry involving nitrogen oxides, carbon monoxide, and volatile organic compounds mainly emitted from fossil fuel combustions and volatile chemical products. Concentrated ozone near the earth's surface has a detrimental impact on the ecosystem and our health. The Los Angeles Basin is a classic example of an urban region with long‐standing ozone pollution, frequently in violation of its standard, designated by the US Environmental

Fair‐weather cumulus clouds are not resolved in regional‐ and global‐scale atmospheric chemistry models because their horizontal extent is less than the horizontal resolution of the model. A Large‐Eddy Simulation (LES) model, with finer grid resolution, can resolve the energy containing turbulent eddies and fair‐weather cumulus clouds. Isoprene, which is mainly emitted from deciduous forests and plays a significant role in producing ozone, has a chemical lifetime similar to the boundary layer tu

Abstract Isoprene, a volatile organic compound that is mainly emitted from trees, rapidly reacts with hydroxyl radical (OH) during daytime and subsequently forms ozone and aerosols in the troposphere. The isoprene‐OH reaction can be affected by the interplay between chemistry and mixing because the two processes occur at a similar time scale. We investigate the impact of turbulent mixing on isoprene‐OH reactivity with large eddy simulations (LES) coupled with comprehensive chemistry. Our results

Abstract A Lagrangian particle dispersion model (LPDM) is used to study fumigation of pollutants in and above the entrainment zone into a growing convective boundary layer. Probability density functions of particle location with height and time are calculated from particle trajectories driven by the sum of the resolved-scale velocity from a large-eddy simulation (LES) model and the stochastic subgrid-scale (SGS) velocity. The crosswind-integrated concentration (CWIC) fields show good agreement w

The subsidence rate in a reclaimed coastal land has been estimated by using JERS‐1 L‐band SAR two‐pass differential interferometry. Measurement of subsidence rate during reclamation is difficult to obtain as a two‐dimensional subsidence map based on sparsely distributed field measurements is required. Owing to the severe temporal decorrelation induced by frequent soil loading and intense deformation gradients, the L‐band was found to be effective for observing subsidence in reclaimed land. We ev

Abstract. Several studies have reported an increasing trend of surface ozone in South Korea over the past few decades, using different measurement metrics. In this study, we examined the surface ozone trends in South Korea by analyzing the hourly or daily maximum 8 h average ozone concentrations (MDA8) measured at the surface from 2001 to 2021. We studied the diurnal, seasonal, and multi-decadal variations of these parameters at city, province, and background sites. We found that the fourth-high

Abstract Abundance of tropospheric ozone is determined by the interplay among emissions, chemistry, and climate dependent transport. It is important to identify the essential factors that modulate ozone in China and Korea because of increasing ozone trends in this area. In this study, we investigated the correlations of tropospheric ozone in East Asia with El Niño Southern Oscillations (ENSO). The model simulated ozone from 2000 to 2020 with Community Atmosphere Model version 6 with chemistry (C