scholarly journals Simulation of Air Quality Over South Korea Using the WRF-Chem Model: Impacts of Chemical Initial and Lateral Boundary Conditions

Atmosphere ◽  
2015 ◽  
Vol 25 (4) ◽  
pp. 639-657 ◽  
Author(s):  
Jae-Hyeong Lee ◽  
Lim-Seok Chang ◽  
Sang-Hyun Lee
Keyword(s):  
Air Quality ◽  
South Korea ◽  
Boundary Conditions ◽  
Lateral Boundary ◽  
Lateral Boundary Conditions

scholarly journals An analysis of long-term regional-scale ozone simulations over the Northeastern United States: variability and trends

2011 ◽  
Vol 11 (2) ◽  
pp. 567-582 ◽  
Author(s):  
C. Hogrefe ◽  
W. Hao ◽  
E. E. Zalewsky ◽  
J.-Y. Ku ◽  
B. Lynn ◽  
...  
Keyword(s):  
Air Quality ◽  
Boundary Conditions ◽  
Interannual Variability ◽  
Ground Level ◽  
Lateral Boundary ◽  
Ground Level Ozone ◽  
Lateral Boundary Conditions ◽  
Ozone Precursor ◽  
Time Invariant

Abstract. This study presents the results from two sets of 18-year air quality simulations over the Northeastern US performed with a regional photochemical modeling system. These two simulations utilize different sets of lateral boundary conditions, one corresponding to a time-invariant climatological vertical profile and the other derived from monthly mean concentrations extracted from archived ECHAM5-MOZART global simulations. The objective is to provide illustrative examples of how model performance in several key aspects – trends, intra- and interannual variability of ground-level ozone, and ozone/precursor relationships – can be evaluated against available observations, and to identify key inputs and processes that need to be considered when performing and improving such long-term simulations. To this end, several methods for comparing observed and simulated trends and variability of ground level ozone concentrations, ozone precursors and ozone/precursor relationships are introduced. The application of these methods to the simulation using time-invariant boundary conditions reveals that the observed downward trend in the upper percentiles of summertime ozone concentrations is captured by the model in both directionality and magnitude. However, for lower percentiles there is a marked disagreement between observed and simulated trends. In terms of variability, the simulations using the time-invariant boundary conditions underestimate observed inter-annual variability by 30%–50% depending on the percentiles of the distribution. The use of boundary conditions from the ECHAM5-MOZART simulations improves the representation of interannual variability but has an adverse impact on the simulated ozone trends. Moreover, biases in the global simulations have the potential to significantly affect ozone simulations throughout the modeling domain, both at the surface and aloft. The comparison of both simulations highlights the significant impact lateral boundary conditions can have on a regional air quality model's ability to simulate long-term ozone variability and trends, especially for the lower percentiles of the ozone distribution.

scholarly journals An analysis of long-term regional-scale ozone simulations over the Northeastern United States: variability and trends

2010 ◽  
Vol 10 (10) ◽  
pp. 23045-23090 ◽  
Author(s):  
C. Hogrefe ◽  
W. Hao ◽  
E. E. Zalewsky ◽  
J.-Y. Ku ◽  
B. Lynn ◽  
...  
Keyword(s):  
Air Quality ◽  
Boundary Conditions ◽  
Interannual Variability ◽  
Ground Level ◽  
Lateral Boundary ◽  
Ground Level Ozone ◽  
Lateral Boundary Conditions ◽  
Ozone Precursor ◽  
Time Invariant

Abstract. This study presents the results from two sets of 18-year air quality simulations over the Northeastern US performed with a regional photochemical modeling system. These two simulations utilize different sets of lateral boundary conditions, one corresponding to a time-invariant climatological vertical profile and the other derived from monthly mean concentrations extracted from archived ECHAM5-MOZART global simulations. The objective is to provide illustrative examples of how model performance in several key aspects – trends, intra- and interannual variability of ground-level ozone, and ozone/precursor relationships – can be evaluated against available observations, and to identify key inputs and processes that need to be considered when performing and improving such long-term simulations. To this end, several methods for comparing observed and simulated trends and variability of ground level ozone concentrations, ozone precursors and ozone/precursor relationships are introduced. The application of these methods to the simulation using time-invariant boundary conditions reveals that the observed downward trend in the upper percentiles of summertime ozone concentrations is captured by the model in both directionality and magnitude. However, for lower percentiles there is a marked disagreement between observed and simulated trends. In terms of variability, the simulations using the time-invariant boundary conditions simulations underestimate observed inter-annual variability by 30–50% depending on the percentiles of the distribution. In contrast, the use of boundary conditions from the ECHAM5-MOZART simulations improves the representation of interannual variability. However, biases in the global simulations have the potential to significantly affect ozone simulations throughout the modeling domain, both at the surface and aloft. The comparison of both simulations highlights the significant impact lateral boundary conditions can have on a regional air quality model's ability to simulate long-term ozone variability and trends, especially for the lower percentiles of the ozone distribution.

scholarly journals Comparison of chemical lateral boundary conditions for air quality predictions over the contiguous United States during pollutant intrusion events

2021 ◽  
Vol 21 (4) ◽  
pp. 2527-2550
Author(s):  
Youhua Tang ◽  
Huisheng Bian ◽  
Zhining Tao ◽  
Luke D. Oman ◽  
Daniel Tong ◽  
...  
Keyword(s):  
Air Quality ◽  
Boundary Conditions ◽  
Model Performance ◽  
Chemical Species ◽  
Saharan Dust ◽  
Atmospheric Composition ◽  
Lateral Boundary ◽  
Model Framework ◽  
Air Quality Forecast ◽  
Lateral Boundary Conditions

Abstract. The National Air Quality Forecast Capability (NAQFC) operated in the US National Oceanic and Atmospheric Administration (NOAA) provides the operational forecast guidance for ozone and fine particulate matter with aerodynamic diameters less than 2.5 µm (PM2.5) over the contiguous 48 US states (CONUS) using the Community Multi-scale Air Quality (CMAQ) model. The existing NAQFC uses climatological chemical lateral boundary conditions (CLBCs), which cannot capture pollutant intrusion events originating outside of the model domain. In this study, we developed a model framework to use dynamic CLBCs from the Goddard Earth Observing System Model, version 5 (GEOS) to drive NAQFC. A mapping of the GEOS chemical species to CMAQ's CB05–AERO6 (Carbon Bond 5; version 6 of the aerosol module) species was developed. The utilization of the GEOS dynamic CLBCs in NAQFC showed the best overall performance in simulating the surface observations during the Saharan dust intrusion and Canadian wildfire events in summer 2015. The simulated PM2.5 was improved from 0.18 to 0.37, and the mean bias was reduced from −6.74 to −2.96 µg m−3 over CONUS. Although the effect of CLBCs on the PM2.5 correlation was mainly near the inflow boundary, its impact on the background concentrations reached further inside the domain. The CLBCs could affect background ozone concentrations through the inflows of ozone itself and its precursors, such as CO. It was further found that the aerosol optical thickness (AOT) from satellite retrievals correlated well with the column CO and elemental carbon from GEOS. The satellite-derived AOT CLBCs generally improved the model performance for the wildfire intrusion events during a summer 2018 case study and demonstrated how satellite observations of atmospheric composition could be used as an alternative method to capture the air quality effects of intrusions when the CLBCs of global models, such as GEOS CLBCs, are not available.

scholarly journals Comparison of Chemical Lateral Boundary Conditions for Air Quality Predictions over the Contiguous United States during Intrusion Events

2020 ◽  
Author(s):  
Youhua Tang ◽  
Huisheng Bian ◽  
Zhining Tao ◽  
Luke D. Oman ◽  
Daniel Tong ◽  
...  
Keyword(s):  
Air Quality ◽  
Boundary Conditions ◽  
Chemical Species ◽  
Saharan Dust ◽  
Lateral Boundary ◽  
Model Framework ◽  
Earth Observing System ◽  
Air Quality Forecast ◽  
Lateral Boundary Conditions ◽  
Chemical Simulation

Abstract. The existing National Air Quality Forecast Capability (NAQFC) operated at NOAA provides operational forecast guidance for ozone and particle matter with aerodynamic diameter less than 2.5 μm (PM2.5) over the contiguous 48 U.S. states (CONUS) using the Community Multi-scale Air Quality (CMAQ) model. Currently NAQFC is using chemical lateral boundary conditions (CLBCs) from a monthly climatology, which cannot capture pollutant intrusion events originated outside of the model domain. In this study, we developed a model framework to introduce the time-varying chemical simulation from the Goddard Earth Observing System Model, version 5 (GEOS) as the CLBCs to drive NAQFC. The method of mapping GEOS chemical species to CMAQ CB05-Aero6 species was also developed. We then evaluated NAQFC's performance using the new CLBCs from GEOS. The utilization of the GEOS dynamic CLBCs showed an overall best score when comparing the NAQFC simulation with the surface observations during the Saharan dust intrusion and Canadian wildfire events in summer 2015: the PM2.5 correlation coefficient R was improved from 0.18 to 0.37 and the mean bias was narrowed from −6.74 μg/m3 to −2.96 μg/m3 over CONUS. The CLBCs' influences depended on not only the distance from the inflow boundary, but also species and their regional characteristics. For the PM2.5 prediction, the CLBC's effect on the correlations was mainly near the inflow boundary, and its impact on the background could reach farther inside the domain. The CLBCs also altered background ozone through the inflows of ozone itself and its precursors. It was further found that aerosol optical thickness (AOT) from VIIRS retrieval correlated well to the column CO and elemental carbon from GEOS, based on which the new CLBCs for wildfire intrusion event was derived. The AOT derived CLBCs successfully captured the wildfire intrusion events in our case study for summer 2018. It can be a useful alternative in case the CLBCs of GEOS are not available.

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