Grantee Research Project Results
Final Report: Impacts of Global Climate and Emission Changes on U.S. Air Quality
EPA Grant Number: R830963Title: Impacts of Global Climate and Emission Changes on U.S. Air Quality
Investigators: Liang, Xin-Zhong , Wuebbles, Donald J. , Huang, Ho-Chun , Williams, Allen , Caughey, Michael , Kunkel, Kenneth , Zhu, Jinhong , Patten, Ken , Hayhoe, Katharine , Lin, Jintai , Tao, Zhining
Institution: University of Illinois Urbana-Champaign
EPA Project Officer: Chung, Serena
Project Period: March 23, 2003 through March 22, 2006 (Extended to September 22, 2007)
Project Amount: $900,000
RFA: Assessing the Consequences of Global Change for Air Quality: Sensitivity of U.S. Air Quality to Climate Change and Future Global Impacts (2002) RFA Text | Recipients Lists
Research Category: Air , Climate Change , Air Quality and Air Toxics
Objective:
Our interest is to better understand how global changes in climate and anthropogenic emissions affect U.S. air quality, especially tropospheric ozone (O3) and fine particulate matter (PM2.5). The ultimate goal is to account for both effects to enable state and local air quality planners to design realistic and effective emission control strategies to meet the National Ambient Air Quality Standards (NAAQS). We propose to apply a state-of-the-art integrated modeling system that nests a global climate-chemical transport model (GCCT) with a regional climate-air quality model (RCAQ) over North America to quantify the individual and combined impacts on U.S. air quality of global climate and emission changes, from the present to 2020, 2050 and 2100. The RCAQ further includes 4 high-resolution subdomains over the U.S. Northeast, Midwest, West Coast and Texas (Fig. 1) for a more detailed assessment of these impacts on local surface ozone, PM2.5, and their precursors. These are the target areas where high probabilities of exceeding the NAAQS for ozone and PM2.5 are anticipated.
The underlying hypothesis of the proposed research is that U.S. air quality is determined by chemical processes and emissions on local to regional scales; long-range transport of global pollutants and precursors originating from global emissions; and global and regional climate changes and variability. We propose to conduct 3 primary sets of experiments, using the integrated modeling system, to rigorously test this hypothesis and address corresponding questions that are important to achieve the EPA goal. Historical simulations of climate and air quality will first be conducted for system validation and for use as a baseline reference for future projections. The system will use the observed and simulated global climate conditions during 1980-2000 together with the concurrent emission inventories to reproduce global chemical transport and, subsequently, U.S. climate and air quality in the past. Future projections for 2020, 2050 and 2100 will then be made, where the system incorporates scenarios of global changes in climate and/or emissions (3 runs per period) to quantify the individual and combined impacts of global climate and emission changes on U.S. air quality. The third set is sensitivity experiments to determine dominant source regions and types (by adding perturbations in the U.S. or global emission inventories), relative roles of episodic transport versus mean background elevation (using transient or mean chemical inflows in RCAQ), as well as uncertainties associated with key conclusions. All experiments will focus on April-October when most air quality episodes occur. Diagnostic studies will identify possible future changes, and their climate and emissions causes, in the frequency, duration, and extreme pollutant concentrations of adverse air quality episodes over the U.S.
The GCCT integrates global climate change and variability with chemical transformations and depositions to determine pollutant transport across nations, oceans and continents that connects natural and anthropogenic source emissions around the world, while providing meteorological and chemical lateral boundary conditions (LBCs) that drive the RCAQ. In contrast, the RCAQ incorporates a more complete physical representation, comprehensive chemical mechanism and detailed emission treatment at a finer grid resolution, and therefore more realistically simulates interactions between atmospheric and surface processes from local to regional scales that in turn affect air quality at a given location. As a result, the integrated system has many advantages, while eliminating many shortcomings, over existing studies with individual component models. In particular, the integration of the nested global-regional climate models offers a unique opportunity to address air quality issues on climate timescales, from seasonal, interannual, and decadal to centurial, of which previous episodic studies are incapable. Our system provides a very cost-effective approach for the timely and advanced study of the impacts of global climate and emissions as well as their projected changes on U.S. air quality, including associated nonlinear interactions across a full range of spatial scales.
The GCCT consists of the National Center for Atmospheric Research (NCAR) Climate System Model version 1.3 (CSM, Boville and Gent 1998, Boville et al. 2001) or the U.S. Department of Energy (DOE) Parallel Climate Model (PCM, Washington et al. 2000), which simulate the present and future global climate variations during 1980-2100; and the Model for OZone And Related chemical Tracers version 2 (MOZART-2, Brasseur et al. 1998, Hauglustaine et al. 1998, Horowitzet al.2003; Wei et al. 2002) that predicts global atmospheric chemical transport. The RCAQ incorporates a Regional Climate Model (RCM, Liang et al. 2001, 2004b) that was developed from the PSU/NCAR MM5 version 3 (Dudhia et al. 2000) with various improvements crucial for climate application; an Air Quality Model (AQM, Huang et al. 2004) that is an advanced version of the SAQM (Chang et al. 1997) with addition of an efficient gas-phase chemistry solver (Huang and Chang 2001), various chemical mechanisms (RADM, CB4, SPARC), and a particulate submodel (Binkowski 1999); and the Sparse Matrix Operator Kernel Emissions modeling system (SMOKE, Houyoux et al. 2000, Williams et al. 2001) using the EPA National Emission Inventory (NEI).
Figure 1. RCAQ domain design for the proposed research. Interactions between mother
domain D1 (30-km grid spacing) adn subdomains D2a-d (10-km grid spacing) can be
one-way, two-way or completely deactivated. The global model provides the RCAQ with
LBCs in the buffer zones (shaded narrow outer edges).
Summary/Accomplishments (Outputs/Outcomes):
With the support of this EPA STAR project, we have published 15 articles and submitted 3 articles in major peer-reviewed journals. We have also made over 30 presentations in major conferences, including invited talks at the U.S. Climate Change Science Program workshop, American Association for the Advancement of Science, American Geophysics Union and American Meteorology Society annual meetings. The abstracts for those published and submitted are given below in this section.
Liang, X.-Z., L. Li, A. Dai, and K.E. Kunkel, 2004: Regional climate model simulation of summer precipitation diurnal cycle over the United States. Geophys. Res. Lett., 31, L24208, doi:10.1029/2004GL021054.
MM5-based regional climate model (CMM5) simulations of the diurnal cycle of U.S. summer precipitation are found to be sensitive to the choice of cumulus parameterization schemes, whose skills are highly regime selective. The Grell (1993) scheme realistically simulates the nocturnal precipitation maxima and their associated eastward propagation of convective systems over the Great Plains where the diurnal timing of convection is controlled by the large-scale tropospheric forcing; whereas the Kain and Fritsch (1993) scheme is more accurate for the late afternoon peaks in the southeast U.S. where moist convection is governed by the near-surface forcing. In radar rainfall data and the simulation with the Grell scheme, another weaker eastward propagating diurnal signal is evident from the Appalachians to the east coast. The result demonstrates the importance of cumulus schemes and provides a realistic simulation of the central U.S. nocturnal precipitation maxima.
Kunkel, K.E., and X.-Z. Liang, 2005: GCM simulations of the climate in the central United States. J. Climate,18, 1016-1031.
A diagnostic analysis of relationships between central U.S. climate characteristics and various flow and scalar fields was used to evaluate nine global coupled ocean–atmosphere general circulation models (CGCMs) participating in the Coupled Model Intercomparison Project (CMIP). To facilitate identification of physical mechanisms causing biases, data from 21 models participating in the Atmospheric Model Intercomparison Project (AMIP) were also used for certain key analyses.
Most models reproduce basic features of the circulation, temperature, and precipitation patterns in the central United States, although no model exhibits small differences from the observationally based data for all characteristics in all seasons. Model ensemble means generally produce better agreement with the observationally based data than any single model. A fall precipitation deficiency, found in all AMIP and CMIP models except the third-generation Hadley Centre CGCM (HadCM3), appears to be related in part to slight biases in the flow on the western flank of the Atlantic subtropical ridge. In the model mean, the ridge at 850 hPa is displaced slightly to the north and to the west, resulting in weaker southerly flow into the central United States.
The CMIP doubled-CO transient runs show warming (1–5°C) for all models and seasons and variable precipitation changes over the central United States. Temperature (precipitation) changes are larger (mostly less) than the variations that are observed in the twentieth century and the model variations in the control simulations.
Zhu, J., and X.-Z. Liang, 2005: Regional climate model simulation of U.S. soil temperature and moisture during 1982-2002. J. Geophys. Res., 110, D24110, doi:10.1029/2005JD006472.
The fifth-generation PSU-NCAR Mesoscale Model (MM5)-based regional climate model (CMM5) capability in simulating the U.S. soil temperature and soil moisture annual cycle and interannual variability is evaluated by comparing the 1982-2002 continuous integration driven by the NCEP-DOE AMIP II reanalysis (R-2) with observations, the R-2 derivatives and North American Land Data Assimilation System (NLDAS) products. For the annual cycle, the CMM5 produces more realistic regional details and overall smaller biases than the driving R-2 and NLDAS outputs. The CMM5 also faithfully simulates interannual variations of soil temperature over the central U.S. and soil moisture in Illinois and Iowa, where observational data are available. The existing CMM5 differences from observations in soil temperature (moisture) cannot be fully explained by model biases in surface air temperature (precipitation). Inconsistencies between measurements taken under short grass versus model representations beneath other land cover types may play an important role. In particular, such measurements overestimate soil temperature in summer and fall while generating a 1-month phase lead in the soil moisture annual cycle with respect to croplands in the model. The result emphasizes the need for more comprehensive study on model evaluation and bias understanding of soil temperature and soil moisture.
Kunkel, K.E., X.-Z. Liang, J. Zhu, and Y. Lin, 2006: Can CGCMs simulate the twentieth Century “warming hole” in the central United States? J. Climate, 19, 4137-4153.
The observed lack of 20th Century warming in the central United States (CUS), denoted here as the “warming hole”, was examined in 55 simulations driven by external historical forcings and in 19 pre-industrial control (unforced) simulations from 18 coupled general circulation models (CGCMs). 20th Century CUS trends were positive for the great majority of simulations, but were negative, as observed, for 7 simulations. Only a few simulations exhibited the observed rapid rate of warming (cooling) during 1901-1940 (1940-1979). Those models with multiple runs (identical forcing but different initial conditions) showed considerable intra-model variability with trends varying by up to 1.8°C/century, suggesting that the historical forcings did not produce consistent trends while internal dynamic variability played a major role at the regional scale. The wide range of trend outcomes, particularly for those models with multiple runs, and the small number of simulations similar to observations in both the forced and unforced experiments suggest that the warming hole is not a robust response of contemporary CGCMs to the estimated external forcings. A more likely explanation based on these models is that the observed warming hole involves external forcings combined with internal dynamic variability that is much larger than typically simulated by these models.
The observed CUS temperature variations are positively correlated with north Atlantic (NA) sea surface temperatures (SSTs) and both NA SSTs and CUS temperature are negatively correlated with central equatorial Pacific (CEP) SSTs. Most models simulate rather well the connection between CUS temperature and NA SSTs. However, the teleconnections between NA and CEP SSTS and between CEP SSTs and CUS temperature are poorly simulated and the models produce substantially less NA SST variability than observed, perhaps hampering their ability to reproduce the warming hole.
Liang, X.-Z., J. Pan, J. Zhu, K.E. Kunkel, J.X.L. Wang, and A. Dai, 2006: Regional climate model downscaling of the U.S. summer climate and future change. J. Geophys. Res., 111, D10108, doi:101029/2005JD006685.
A mesoscale model (MM5)-based regional climate model (CMM5) integration driven by the Parallel Climate Model (PCM), a fully coupled atmosphere-ocean-land-ice general circulation model (GCM), for the present (1986-1995) summer season climate is first compared with observations to study the CMM5’s downscaling skill and uncertainty over the United States. The results indicate that the CMM5, with its finer resolution (30 km) and more comprehensive physics, simulates the present U.S. climate more accurately than the driving PCM, especially for precipitation, including summer mean patterns, diurnal cycles and daily frequency distributions. Hence, the CMM5 downscaling provides a credible means to improve GCM climate simulations. A parallel CMM5 integration driven by the PCM future (2041-2050) projection is then analyzed to determine the downscaling impact on regional climate changes. It is shown that the CMM5 generates climate change patterns very different than those predicted by the driving PCM. A key difference is a summer “warming hole” over the central U.S. in the CMM5 relative to the PCM. This study shows that the CMM5 downscaling can significantly reduce GCM biases in simulating the present climate and that this improvement has important consequences for future projections of regional climate changes. For both the present and future climate simulations, the CMM5 results are sensitive to the cumulus parameterization, with strong regional dependence. The deficiency in representing convection is likely the major reason for the PCM’s unrealistic simulation of U.S. precipitation patterns and perhaps also for its large warming in the central U.S.
Zhu, J., and X.-Z. Liang, 2007: Regional climate model simulation of U.S. precipitation and surface air temperature during 1982-2002: Interannual variation. J. Climate, 20, 218-232.
The fifth-generation PSU-NCAR Mesoscale Model-based regional climate model (CMM5) capability in simulating the interannual variations of U.S. precipitation and surface air temperature during 1982-2002 is evaluated with a continuous baseline integration driven by the NCEP-DOE Second Atmospheric Model Intercomparison Project reanalysis (R-2). It is demonstrated that the CMM5 has a pronounced downscaling skill for precipitation and temperature interannual variations. The EOF and correlation analyses illustrate that, for both quantities, the CMM5 captures the spatial pattern, temporal evolution and circulation teleconnections much better than the R-2. In particular, the CMM5 more realistically simulates the precipitation pattern centered in the Northwest, where the representation of the orographic enhancement by the forced uplifting during winter (rainy season) is greatly improved over the R-2.
The downscaling skill, however, is sensitive to the cumulus parameterization. This sensitivity is studied by comparing the baseline with a branch summer integration replacing the Grell with the Kain-Fritsch cumulus scheme in the CMM5. The dominant EOF mode of the U.S. summer precipitation interannual variation, identified with the out-of-phase relationship between the Midwest and Southeast in observations, is reproduced more accurately by the Grell than Kain-Fritsch scheme, which largely underestimates the variation in the Midwest. This pattern is associated with east-west movement of the Great Plains low-level jet (LLJ): a more western position corresponds to a stronger southerly flow bringing more moisture and heavier rainfall in the Midwest and less in the Southeast. The second EOF pattern, which describes the consistent variation over the southern part of the Midwest and the South in observations, is captured better by the Kain-Fritsch scheme than the Grell whose pattern systematically shifts southward.
Huang, H.-C., X.-Z. Liang, K. E. Kunkel, M. Caughey, and A. Williams, 2007: Seasonal simulation of tropospheric ozone over the Midwest and Northeast U.S.: An application of a coupled regional climate and air quality modeling system. J. Appl. Meteor. Clim., 46, 945-960.
The impacts of air pollution on the environment and human health could increase as a result of potential climate change. To assess such possible changes, model simulations of pollutant concentrations need to be performed at climatic (seasonal) rather than episodic (days) time scales, using future climate projections from a general circulation model. Such a modeling system was employed here, consisting of a regional climate model (RCM), an emissions model, and an air quality model. To assess overall model performance with one-way coupling, this system was used to simulate tropospheric ozone concentrations in the Midwestern and northeastern United States for summer seasons between 1995 and 2000. The RCM meteorological conditions were driven by the National Centers for Environmental Prediction/Department of Energy global reanalysis (R-2) using the same procedure that integrates future climate model projections. Based on analyses for several urban and rural areas and regional domains, fairly good agreement with observations was found for the diurnal cycle and for several multiday periods of high ozone episodes. Even better agreement occurred between monthly and seasonal mean quantities of observed and model-simulated values. This is consistent with an RCM designed primarily to produce good simulations of monthly and seasonal mean statistics of weather systems.
Liang, X.-Z., M. Xu, K.E. Kunkel, G.A. Grell, and J. Kain, 2007: Regional climate model simulation of U.S.-Mexico summer precipitation using the optimal ensemble of two cumulus parameterizations. J. Climate, 20, 5201-5207.
Regional climate model (CMM5) simulations of U.S.-Mexico summer precipitation are quite sensitive to the choice of Grell or Kain-Fritsch convective parameterization. An ensemble based on these two parameterizations provides superior performance because distinct regions exist where each scheme complementarily captures certain observed signals. For the interannual anomaly, the ensemble provides the most significant improvement over the Rockies, Great Plains and North American monsoon region. For the climate mean, the ensemble has the greatest impact on skill over the Southeast U.S. and North American monsoon region, where CMM5 biases associated with the individual schemes are of opposite sign. Results are very sensitive to the specific methods used to generate the ensemble. While equal weighting of individual solutions provides a more skillful result overall, considerable further improvement is achieved when the weighting of individual solutions is optimized as a function of location.
Kunkel, K.E., H.-C. Huang, X.-Z. Liang, J.-T. Lin, D.J. Wuebbles, Z. Tao, A. Williams, M. Caughey, J. Zhu, and K. Hayhoe, 2007: Sensitivity of future ozone concentrations in the Northeast USA to regional climate change. Mitig. Adapt. Strat. Glob. Change, DOI 10.1007/s11027-007-9137-y.
An air quality modeling system was used to simulate the effects on ozone concentration in the northeast USA from climate changes projected through the end of the twenty-first century by the National Center for Atmospheric Research’s (NCAR’s) parallel climate model, a fully coupled general circulation model, under a higher and a lower scenario of future global changes in concentrations of radiatively active constituents. The air quality calculations were done with both a global chemistry-transport model and a regional air quality model focused on the northeast USA. The air quality simulations assumed no changes in regional anthropogenic emissions of the chemical species primarily involved in the chemical reactions of ozone creation and destruction, but only accounted for changes in the climate. Together, these idealized global and regional model simulations provide insights into the contribution of possible future climate changes on ozone. Over the coming century, summer climate is projected to be warmer and less cloudy for the northeast USA. These changes are considerably larger under the higher scenario as compared with the lower. Higher temperatures also increase biogenic emissions. Both mean daily and 8-h maximum ozone increase from the combination of three factors that tend to favor higher concentrations: higher temperatures change the rates of reactions and photolysis rates important to the ozone chemistry; (2) lower cloudiness (higher solar radiation) increases the photolysis reaction rates; and (3) higher biogenic emissions increase the concentration of reactive species. Regional model simulations with two cumulus parameterizations produce ozone concentration changes that differ by approximately 10%, indicating that there is considerable uncertainty in the magnitude of changes due to uncertainties in how physical processes should be parameterized in the models. However, the overall effect of the climate changes simulated by these models – in the absence of reductions in regional anthropogenic emissions –would be to increase ozone concentrations.
Tao, Z., A. Williams, H.-C. Huang, M. Caughey, and X.-Z. Liang, 2007: Sensitivity of U.S. surface ozone to future emissions and climate changes. Geophys. Res. Lett., 34, L08811, doi:10.1029/2007GL029455.
The relative contributions of projected future emissions and climate changes to U.S. surface ozone concentrations are investigated focusing on California, the Midwest, the Northeast, and Texas. By 2050 regional average ozone concentrations increase by 2–15% under the IPCC SRES A1Fi (‘‘dirty’’) scenario, and decrease by 4–12% under the B1 (relatively ‘‘clean’’) scenario. However, the magnitudes of ozone changes differ significantly between major metropolitan and rural areas. These ozone changes are dominated by the emissions changes in 61% area of the contiguous U.S. under the B1 scenario, but are largely determined by the projected climate changes in 46% area under the A1Fi scenario. In the ozone responses to climate changes, the biogenic emissions changes contribute strongly over the Northeast, moderately in the Midwest, and negligibly in other regions.
Lin, J.T., K.O. Patten, X.-Z. Liang, and D.J. Wuebbles, 2008: Effects of Future Climate and Biogenic Emissions Changes on Surface Ozone over the United States and China. J. Appl. Meteorol. Clim. (in press).
Projections of future air quality depend on the choice of both climate and emissions scenarios. This is investigated by comparing summertime ozone changes from 1996–2000 to 2095–2099, simulated by the Model for OZone And Related chemical Tracers version 2.4, in response to climate projections by the Parallel Climate Model and corresponding biogenic emissions and methane perturbations under the Intergovernmental Panel on Climate Change A1fi and B1 scenarios. By incorporating only the projected climate changes without altering biogenic emissions and methane, the magnitudes of the ozone responses in both the U.S. and China are within 6 parts per billion (ppb), often less than 3 ppb. The spatial patterns of the responses, however, substantially differ between A1fi and B1. Over the U.S., ozone increases are simulated in much of the inland eastern region under A1fi but in the western region under B1, while decreases are produced along the coasts under both scenarios. Over China, ozone increases in the northern area but decreases in the southern area under both scenarios. These regional ozone increases and decreases are identified mainly with the local air temperature warming and the marine air dilution enhancement, respectively. When changes in climate, biogenic emissions and methane are incorporated together, the magnitudes of the ozone responses differ greatly between the two scenarios, with increases of 3–12 ppb under A1fi and 0–6 ppb under B1 over both countries. Thus the projected ozone responses are dominated by the biogenic emissions and methane perturbations under these different scenarios.
Hayhoe, K., C. Wake, B. Anderson, X.-Z. Liang, E. Maurer, J. Zhu, J. Bradbury, A. DeGaetano, A. Hertel, and D. Wuebbles, 2007: Regional climate change projections for the Northeast USA. Mitig. Adapt. Strat. Glob., DOI 10.1007/s11027-007-9133-2.
Climate projections at relevant temporal and spatial scales are essential to assess potential future climate change impacts on climatologically diverse regions such as the northeast United States. Here, we show how both statistical and dynamical downscaling methods applied to relatively coarse-scale atmosphere-ocean general circulation model output are able to improve simulation of spatial and temporal variability in temperature and precipitation across the region. We then develop high-resolution projections of future climate change across the northeast USA, using IPCC SRES emission scenarios combined with these downscaling methods. The projections show increases in temperature that are larger at higher latitudes and inland, as well as the potential for changing precipitation patterns, particularly along the coast. While the absolute magnitude of change expected over the coming century depends on the sensitivity of the climate system to human forcing, significantly higher increases in temperature and in winter precipitation are expected under a higher as compared to lower scenario of future emissions from human activities.
Vrac, M., M. Stein, K. Hayhoe, and X.-Z. Liang, 2007: A general method for validating statistical downscaling methods under future climate change. Geophys. Res. Lett., 34, L18701, doi:10.1029/2007GL030295.
Statistical downscaling methods (SDMs) are often used to increase the resolution of future climate projections from coupled atmosphere-ocean general circulation models (GCMs). However, SDMs are not able to capture small-scale dynamical changes unresolved by GCMs. For this reason, we propose a two-step generalized validation process to evaluate the performance of any statistical downscaling method relative to regional climate model (RCM) simulations driven by the same GCM fields. First, we compare historical station-based observations with simulations obtained from a statistical model fitted to and driven by reanalysis fields, and then driven by historical GCM fields. Then, the SDM is required to produce future projections consistent with RCM simulations used as pseudo-observations under future emissions scenarios. Using the climate extension of the fifth generation Penn-State/NCAR Mesoscale Model (CMM5) driven by NCAR/DOE Parallel Climate Model (PCM) simulations, we apply this method to identify the strengths/weaknesses of a nonhomogeneous stochastic weather typing method.
Tao, Z., A. Williams, H.-C. Huang, M. Caughey, and X.-Z. Liang. 2008: Sensitivity of Surface Ozone Simulation to Cumulus Parameterization. J. Appl. Meteorol. Clim. (in press).
Different cumulus schemes cause significant discrepancies in simulated precipitation, cloud cover, and temperature, which in turn lead to remarkable differences in simulated biogenic volatile organic compound (BVOC) emissions and surface ozone concentrations. As part of an effort to investigate the impact (and its uncertainty) of climate changes on U.S. air quality, this study evaluates the sensitivity of BVOC emissions and surface ozone concentrations to the Grell (GR) and Kain-Fritsch (KF) cumulus parameterizations. Overall, using the KF scheme yields less cloud cover, larger incident solar radiation, warmer surface temperature, higher boundary layer height, and hence, generates more BVOC emissions than those using the GR scheme. As a result, the KF (versus GR) scheme produces more than 10 ppb of summer mean daily maximum 8-hour ozone concentration over broad regions, resulting in a doubling of the number of high ozone occurrences. The contributions of meteorological conditions versus BVOC emissions on regional ozone sensitivities to the choice of the cumulus scheme largely offset each other in the California and Texas regions, but the contrast in BVOC emissions dominates over that in the meteorological conditions for ozone differences in the Midwest and Northeast regions. The result demonstrates the necessity of considering the uncertainty of future ozone projections that are identified with alternative model physics configurations.
Lin, J.T., K.O. Patten, X.-Z. Liang, and D.J. Wuebbles, 2008: Effects of intercontinental transport on surface ozone over the United States at the present and future. Geophys. Res. Lett., 35, L02805, doi:10.1029/2007GL031415.
Intercontinental transport (ICT) of European and Asian (EURA) pollutants can have substantial consequences on U.S. air quality. A suite of 27 simulations using a newly improved version of the Model for OZone And Related chemical Tracers (MOZART) is conducted to study the ICT contributions to summertime U.S. surface ozone for the present (1999) and future (2049, 2099). The future conditions are projected by the Parallel Climate Model (PCM) under the Intergovernmental Panel on Climate Change (IPCC) A1Fi and B1 scenarios. The primary impacts of future ICT changes due to EURA anthropogenic emissions projections are found over the western U.S., where they result in 3–8 ppb (2–6 ppb by Asian emissions alone) more ozone from 1999 to both 2049 and 2099 under A1Fi while respectively 0–0.7 ppb and 1–2 ppb less ozone under B1. Therefore global, especially Asian, emissions control is important for U.S. pollution mitigation.
Huang, H.-C., X.-Z. Liang, K.E. Kunkel, A. Williams, M. Caughey, and Z. Tao, 2007: Simulation of continental US air quality on climatic time scales under present-day conditions. J. Geophys. Res. (submitted).
Simulations of the present-day climate (1996-2000) were analyzed to establish a baseline that will be used to assess air quality simulations driven by future climate change scenarios. The modeling system consisted of an emissions model, a regional climate model (RCM), and an air quality model (AQM). The Sparse Matrix Operator Kernel Emissions modeling system was used to process US, Canadian, and Mexican inventory data. The RCM was driven by the National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) Atmospheric Model Intercomparison Project (AMIP-II) reanalysis data and the Parallel Climate Model present-day climate simulation. The AQM was developed from the SARMAP Air Quality Model (SAQM). Sensitivity of AQM results to the cumulus parameterization was investigated by repeating simulations for the Grell and the Kain-Fritsch cumulus schemes. The Grell scheme simulations generally agree better with air quality observations in the Midwest-Northeast US and Texas regions. In addition to the local temperature evolution, AQM simulations also were influenced by changes in transport patterns and mixing processes, which most likely resulted from the driving lateral boundary conditions of the global dataset, especially along the US West Coast. Sensitivity of the results to meteorological conditions indicates the need for a carefully chosen set of climate conditions, including driving general circulation model simulations and choice of physical parameterizations, to quantify the uncertainties of future air quality.
Huang, H.-C., Z. Tao, A. Williams, M. Caughey, X.-Z. Liang, K.E. Kunkel, and J.X.L. Wang, 2007: The potential changes of continental US air quality in future climates. J. Geophys. Res. (submitted).
To assess potential climate change impacts on US air quality, present-day and future simulations (2048-2052 and 2095-2099) of surface ozone were performed. The modeling system consisted of an emissions model coupled with a regional climate model (RCM) and an air quality model (AQM). Two GCMs, the Parallel Climate Model and the HadCM3 model were used to provide lateral boundary conditions for the RCM. GCM simulations were available for four IPCC marker emissions scenarios, A1Fi, A2, B1, and B2. Two RCM cumulus parameterizations, the Grell (GR) and the Kain-Fritsch (KF) schemes, were used to represent the uncertainty of RCM physical representation. AQM simulations for present and future climates were performed using six combinations of modeling components and emission scenarios to quantify the uncertainty of the climatic air quality changes focused on tropospheric ozone. Sensitivity of the results to the selected model configuration is large. The changes in daily mean and mean daily maximum 8-hr average ozone concentration ranged from -27% to +42% and -31% to +51%, respectively. The A1Fi scenario generally produced a substantial increase in both the surface concentration and the projected exceedence days, while the B1 scenario produced a significant decrease. Simulations using the KF cumulus parameterization scheme often produced a higher increase of surface concentration than that of the GR scheme. The Northeast US has the largest sensitivity to the modeling configuration (-24% to +42%), followed by the Midwest US (-19% to +41%). However, at the coarser resolution (90km), the Southeast US shows the largest sensitivity (-30% to +59%).
Huang, H.-C., J. Lin, Z. Tao, H. Choi, K. Patten, K.E. Kunkel, M. Xu, J. Zhu, X-Z. Liang, A. Williams, M. Caughey, D.J. Wuebbles, and J.X.L. Wang, 2007: Impacts of long-range transport of global pollutants and precursor gases on US air quality under future climatic conditions. J. Geophys. Res. (submitted).
Both current and projected future United States (US) air quality is impacted by emissions both within and outside the US. Appropriate lateral boundary conditions (LBCs) used in regional model simulations are critical to accounting for this impact. A global chemical and transport model (MOZART) and a regional air quality modeling (RAQM) system were used to investigate the influence of long range transport (LRT) on present US air quality. Simulation results showed that each selected region, i.e. Northeast US, Midwest US, Texas, California, and Southeast US, was affected by the LRT in a different way. To understand the LRT impact in response to projected global climate and emissions changes, the MOZART and RAQM simulations were repeated for future climates (2048-2052 and 2095-2099) under two emissions scenarios (IPCC A1Fi and B1). The future US air quality projected by the MOZART is less sensitive to the emissions scenarios than that simulated by the RAQM. The results of RAQM with the MOZART LBCs showed that the Southeast US has the largest sensitivity of surface ozone concentration to the emissions changes in the 2095-2099 climate (-23.8% to +24.7%) followed by the Northeast and Midwest US. The net increase due to the LRT in 2095-2099 ranges from +4.4% to +12.5% in daily mean surface ozone concentration and +3.5% to +10.9% in mean daily maximum 8-hr average ozone concentrations. The regional total column O3 concentrations have increases ranging from +6.6% to +15.8% while the simulated number of exceedence days generally show an increase of 2 to 3 days due to the LRT in 2095-2099. The results indicate that future U.S. air quality changes will be substantially affected by global emissions.
Conclusions:
This project has been officially closed. We will continue to disseminate our results from this STAR project to the public, through publications in peer-reviewed journals and books and also presentations at major conferences and institutions.
Journal Articles on this Report : 17 Displayed | Download in RIS Format
Other project views: | All 37 publications | 18 publications in selected types | All 18 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Hayhoe K, Wake C, Anderson B, Liang X-Z, Maurer E, Zhu J, Bradbury J, DeGaetano A, Stoner AM, Wuebbles D. Regional climate change projections for the Northeast USA. Mitigation and Adaptation Strategies for Global Change 2008;13(5-6):425-436. |
R830963 (Final) |
Exit |
|
Huang H-C, Liang X-Z, Kunkel KE, Caughey M, Williams A. Seasonal simulation of tropospheric ozone over the Midwestern and Northeastern United States:an application of a coupled regional climate and air quality modeling system. Journal of Applied Meteorology and Climatology 2007;46(7):945-960. |
R830963 (2005) R830963 (2006) R830963 (Final) |
Exit Exit Exit |
|
Huang H-C, Lin JT, Tao Z, Choi H, Patten K, Kunkel K, Xu M, Zhu J, Liang X-Z, Williams A, Caughey M, Wuebbles DJ, Wang J. Impacts of long-range transport of global pollutants and precursor gases on U.S. air quality under future climatic conditions. Journal of Geophysical Research–Atmospheres 2008;113(D19):D19307 (15 pp.). |
R830963 (Final) R833373 (Final) |
Exit Exit |
|
Kunkel KE, Liang X-Z. GCM simulations of the climate in the central United States. Journal of Climate 2005;18(7):1016-1031. |
R830963 (2003) R830963 (2004) R830963 (2005) R830963 (2006) R830963 (Final) |
Exit Exit Exit |
|
Kunkel KE, Liang X-Z, Zhu J, Lin Y. Can CGCMs simulate the twentieth-century "warming hole" in the central United States? Journal of Climate 2006;19(17):4137-4153. |
R830963 (2005) R830963 (2006) R830963 (Final) |
Exit Exit Exit |
|
Kunkel KE, Huang H-C, Liang X-Z, Lin J-T, Wuebbles D, Tao Z, Williams A, Caughey M, Zhu J, Hayhoe K. Sensitivity of future ozone concentrations in the northeast USA to regional climate change. Mitigation and Adaptation Strategies for Global Change 2008;13(5-6):597-606. |
R830963 (2006) R830963 (Final) |
Exit Exit Exit |
|
Liang X-Z, Li L, Dai A, Kunkel KE. Regional climate model simulation of summer precipitation diurnal cycle over the United States. Geophysical Research Letters 2004;31(24):L24208 (4 pp.). |
R830963 (2003) R830963 (2004) R830963 (2005) R830963 (2006) R830963 (Final) |
Exit Exit |
|
Liang X-Z, Pan J, Zhu J, Kunkel KE, Wang JXL, Dai A. Regional climate model downscaling of the U.S. summer climate and future change. Journal of Geophysical Research--Atmospheres 2006;111(D10):D10108 (17 pp.). |
R830963 (2005) R830963 (2006) R830963 (Final) |
Exit Exit |
|
Liang X-Z, Xu M, Kunkel KE, Grell GA, Kain JS. Regional climate model simulation of U.S.-Mexico summer precipitation using the optimal ensemble of two cumulus parameterizations. Journal of Climate 2007;20(20):5201-5207. |
R830963 (2006) R830963 (Final) |
Exit Exit Exit |
|
Liang X-Z, Kunkel KE, Meehl GA, Jones RG, Wang JXL. Regional climate models downscaling analysis of general circulation models present climate biases propagation into future change projections. Geophysical Research Letters 2008;35(8):L08709 (5 pp.). |
R830963 (Final) R833373 (Final) |
Exit Exit |
|
Lin J-T, Patten KO, Hayhoe K, Liang X-Z, Wuebbles DJ. Effects of future climate and biogenic emissions changes on surface ozone over the United States and China. Journal of Applied Meteorology and Climatology 2008;47(7):1888-1909. |
R830963 (2006) R830963 (Final) |
Exit Exit Exit |
|
Lin J-T, Wuebbles DJ, Liang X-Z. Effects of intercontinental transport on surface ozone over the United States:present and future assessment with a global model. Geophysical Research Letters 2008;35(2):L02805 (6 pp.). |
R830963 (Final) R833373 (Final) |
Exit Exit |
|
Tao Z, Williams A, Huang H-C, Caughey M, Liang X-Z. Sensitivity of U.S. surface ozone to future emissions and climate changes. Geophysical Research Letters 2007;34(8):L08811 (5 pp.). |
R830963 (2006) R830963 (Final) R831449 (2006) R831449 (Final) |
Exit Exit |
|
Tao Z, Williams A, Huang H-C, Caughey M, Liang X-Z. Sensitivity of surface ozone simulation to cumulus parameterization. Journal of Applied Meteorology and Climatology 2008;47(5):1456-1466. |
R830963 (2006) R830963 (Final) R831449 (Final) |
Exit Exit Exit |
|
Vrac M, Stein ML, Hayhoe K, Liang X-Z. A general method for validating statistical downscaling methods under future climate change. Geophysical Research Letters 2007;34(18):L18701 (5 pp.). |
R830963 (Final) R829402 (Final) R829402C006 (Final) |
Exit Exit |
|
Zhu J, Liang X-Z. Regional climate model simulation of U.S. soil temperature and moisture during 1982-2002. Journal of Geophysical Research-Atmospheres 2005;110(24):D24110 (12 pp.). |
R830963 (2004) R830963 (2005) R830963 (2006) R830963 (Final) |
Exit Exit |
|
Zhu J, Liang X-Z. Regional climate model simulations of U.S. precipitation and surface air temperature during 1982–2002: interannual variation. Journal of Climate 2007;20(2):218-232. |
R830963 (2006) R830963 (Final) |
Exit Exit Exit |
Supplemental Keywords:
climate change, emission, pollutant transport, scale interaction, ozone, nitrogen oxides, sulfate, particular matter, regional climate model, air quality model,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, particulate matter, Air Quality, Air Pollutants, Chemistry, climate change, Air Pollution Effects, Monitoring/Modeling, Atmospheric Sciences, Environmental Engineering, Atmosphere, anthropogenic stress, aerosol formation, ambient aerosol, atmospheric particulate matter, atmospheric dispersion models, environmental monitoring, environmental measurement, meteorology, climatic influence, emissions monitoring, future projections, global change, ozone, air quality models, climate models, greenhouse gases, airborne aerosols, atmospheric aerosol particles, atmospheric transport, environmental stress, regional emissions model, ecological models, climate model, greenhouse gas, aerosols, atmospheric models, Global Climate Change, atmospheric chemistry, ambient air pollutionProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- 2006 Progress Report
- 2005 Progress Report
- 2004 Progress Report
- 2003 Progress Report
- Original Abstract
18 journal articles for this project