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Highlights

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Past Highlights  

January - March 2008

United Nations Environment Program Report on Mercury Air Transport and Fate Research. A Division scientist assisted in the development of a report coordinated by the United Nations Environment Program (UNEP) Global Partnership on Mercury Air Transport and Fate Research. This report, entitled the UNEP Mercury Transport and Fate Report (T&F Report) is a step forward from the UNEP 2002 Global Mercury Assessment report and from the synthesis papers prepared by five expert panels at the last International Conference as a Global Pollutant (ICMGP) held in Madison, USA in August 2006, which have been published in Ambio (February 2007) by the Royal Swedish Academy of Science. As a member of the ICMGP expert panel on “Attributing Sources of Mercury Deposition,” the Division scientist was asked to be lead author on a chapter of the T&F Report regarding the importance of intercontinental transport on regional mercury modeling. An initial draft of the T&F Report will be composed at a meeting beginning April 7-11, 2008 in Rome, Italy, in coordination with the United Nations Economic Commission for Europe convention on Long-Range Transport of Air Pollution. o.russell.bullock@noaa.gov

Parameterization of Heterogeneous N2O5 Reaction Probability. Model results for wintertime particulate nitrate are sensitive to the heterogeneous reaction probability of dinitrogen pentoxide on particle surfaces (γN2O5). Last quarter, Division scientists published a new parameterization of γN2O5 for particles containing sulfate, nitrate, and ammonium (Davis, Bhave, and Foley, ACPD, 7:16119-16153, 2007). The publication of this parameterization stirred up some debate regarding the dependence of γN2O5 on relative humidity (RH) at RH > 50%. This quarter, further research was conducted on this topic including an extensive survey of laboratory measurements of γN2O5 on various water-soluble substrates. An alternative parameterization of γN2O5 has been developed and will be tested in the Community Multiscale Air Quality (CMAQ) model in preparation for the upcoming public release.  Motivated by the results of our work, EPA scientists approached Division scientists to plan a set of laboratory experiments aimed at improving the parameterization of γN2O5 in future versions of the CMAQ model. prakash.bhave@noaa.gov, kristen.foley@noaa.gov

Secondary Organic Aerosol Module Upgrade. Division scientists made a major upgrade to the Community Multiscale Air Quality (CMAQ) model treatment of secondary organic aerosol (SOA) species. During this quarter, several test simulations were conducted in preparation for the upcoming public release of the CMAQ model. Model simulations of summer 2003, January 2006, and August 2006, have been conducted using the newly developed SOA module and the previous SOA module. Preliminary results suggest that predictions using the new SOA module exhibit better seasonal and spatial patterns for aromatic and biogenic SOA and predictions of total carbon exhibit a diurnal profile that is consistent with observations. Model results are being evaluated against source-specific organic carbon measurements in Research Triangle Park and semi-continuous organic and elemental carbon measurements in Duke Forest. Work is also underway to better couple global and regional air quality models by developing boundary conditions for CMAQ using Goddard Earth Observing System chemistry predictions. Well-defined boundaries in both time and space are important for some of the new SOA species, which have precursors with long chemical lifetimes. annmarie.carlton@noaa.gov, sergey.napelenok@noaa.gov, prakash.bhave@noaa.gov

Air Quality Model Evaluation International Initiative. Following on a successful workshop in August 2007 covering the evaluation of regional-scale numerical air quality modeling systems in North America, a Steering Committee has been formed to explore the possibility of holding a similar Workshop in Europe to extend the discussions to an international audience, and compare and contrast evaluation techniques on both continents. The Steering Committee is composed of about 20 members from modeling organizations in Europe, U.S., and Canada. The Steering Committee met in person for the first time during April 3-4, 2008 at the Netherlands organization for Applied Scientific Research offices in Utrecht, Netherlands. The meeting was chaired by the organizers, Dr. S.T. Rao of NOAA/ARL/ASMD and Dr. Stephano Galmarini of Joint Research Center, Ispra, Italy. The first day was composed mostly of presentations and discussion on various model evaluation topics. Ken Schere (ARL/ASMD) made a presentation on a summary and lessons learned from the 2007 North American Workshop. The advances in probabilistic (ensemble) modeling from some of the European presenters (S. Galmarini-Italy, R. Vautard-France) were particularly interesting. The remainder of the discussion focused on planning for a 2009 Workshop. It is hoped that this Workshop will help set a modeling research agenda for the next decade. The dates were set to April 6-8, 2009 with the venue in Europe to be decided after funding sources are identified. It is envisioned that 50-60 participants would attend, with significant participation from the U.S. and Canada. Steering Committee members will start refining the science questions to be addressed at the Workshop. st.rao@noaa.gov, kenneth.schere@noaa.gov

Regional Air Quality Model Evaluation Report. A Workshop on the evaluation of regional-scale air quality modeling systems was held during August 7-8, 2007 in Research Triangle Park, NC, sponsored by the American Meteorological Society and the U.S. EPA, and was attended by over 90 members of the air quality modeling community. Some of the ideas discussed at the Workshop are being captured in a manuscript developed by members of the Workshop’s Steering Committee. A framework for model evaluation is presented, composed of several perspectives on model evaluation including operational (are we getting the right answers), diagnostic (are we getting the right answers for the right reasons), dynamic (does the model correctly simulate changes due to emissions and meteorology), and probabilistic (what is our confidence in the model predictions). New evaluation techniques for regional scale models are emphasized, and modeling uncertainty is explored through the use of ensemble and Bayesian methods. The Steering Committee hopes to complete the draft manuscript and submit for review by summer 2008. The model evaluation framework presented here has also been embraced by the Steering Committee for the new Air Quality Model Evaluation International Initiative, a joint European, U.S., and Canadian project. kenneth.schere@noaa.gov

Air Quality Forecast Model Development and Testing. In preparation for the 2008 implementation of the National Air Quality Forecast Guidance system, a number of upgrades to both, the Community Multiscale Air Quality (CMAQ) model and a pre-processor for CMAQ (PREMAQ) code configurations, as well as input emission data sets were tested. The interface processor, PREMAQ, was updated to include an alternate formulation of the aerodynamic resistance term used in estimation of dry deposition velocities, modifications to speciate emission data sets compatible with both the CBM-IV and the updated CB-05 chemical mechanisms, and to accommodate data sets with alternate mobile emissions estimates. The CMAQ code was updated to include the CB05 chemical mechanism. A number of simulations over a retrospective period in 2007 were performed to test various changes in the modeling system and included testing of:

Changes were also incorporated in the CMAQ input/output structure to facilitate the application of the model on a 60-layer configuration that exactly matches the layer configuration employed in the driving NAM model. Simulations with this CMAQ configuration will be used to assess the impacts of using a reduced layer structure in operations. Efforts were also devoted towards improving the representation of O3 in the free troposphere. The stratospheric influence on O3 was parameterized by enforcing the condition of proportionality to Potential Vorticity (PV) in the top CMAQ layer (~100mb); spatially and temporally varying PV fields were estimated from the NAM fields. Extensive comparisons of resultant simulated profiles with measurements from the ozonesonde launches during the 2006 Texas Field Study indicated improved representation of simulated O3 vertical structure. The approach is being further refined to include a PV-based scaling for specification of lateral boundary conditions as well as in developing a more robust constant of proportionality. rohit.mathur@noaa.gov, george.pouliot@noaa.gov, jonathon.pleim@noaa.gov, jeff.young@noaa.gov, david.wong@noaa.gov

SCIENTIFIC ACCOMPLISHMENTS

Modeling the Diffuse Sky Radiance as a Function of Surface Albedo. Surface reflectance acts as an additional light source to the atmosphere. Non-zero surface albedo contributes, therefore, to actinic flux generally, and specifically to down welling irradiance through multiple scattering. The diffuse sky radiance associated with surface- reflected light is azimuthally symmetric (i.e. has no azimuthal dependence). This fact, together with knowledge of the relative increase in down welling irradiance due to surface albedo (which serves as a boundary condition), reduces the problem of modeling albedo’s contribution to diffuse sky radiance to the unknown zenith angle dependence. This unknown can be further constrained by the realization that the ratio of the relative increase in radiance with a change in albedo for a any given zenith angle, to the relative increase in radiance with the same change in albedo for a reference zenith angle (e.g. zenith angle (z)  = 0), is independent of the change in albedo.  Expressed as an equation, with L = radiance [W/m2/nm/sr], α = albedo [-],

equation 1

 

Thus, the change in radiancewith changes in surface albedo can be determined for all zenith angles (and therefore all directions) by solving the following boundary condition for κ:

equation2

 

It is possible to determine the dependence of radiance on albedo, and hence the contribution of albedo to actinic flux. john.streicher@noaa.gov

In-lining Emissions and Deposition Calculations in the Community Multiscale Air Quality (CMAQ) model. The effort to bring the capability of calculating the deposition velocity directly in the Community Multiscale Air Quality (CMAQ) model has been completed. The CMAQ code for this method has been installed in the Division's code repository. Work continues to finalize the in-line point source plume rise capability. Along with the in-line biogenics emissions, these improvements in CMAQ will allow a better time-resolved representation of these processes. Additionally, the size of the emissions input files is significantly reduced at the expense of calculating plume rise in CMAQ. The in-line biogenic emissions have been successfully tested. The plume rise development appears to be in its final stages of testing, and should be available for model usage shortly. Also, this quarter, work was completed to upgrade the python code that generates the gas chemistry CMAQ include files from information supplied by the chemical mechanism processing software. The updates included extending the capability of having more than 100 gas phase species and allowing a species name to have up to 16 characters. jeff.young@noaa.gov

In-lining Photolysis Rate Calculations in the Community Multiscale Air Quality (CMAQ) model. In-lined photolysis calculation from Carolina Environmental Program (CEP) was incorporated into Community Multiscale Air Quality (CMAQ). Unit testing was conducted and the results were presented at the monthly CMAQ model development meeting. Incremental testing and analysis are presently being performed. david.wong@noaa.gov

Evaluating Community Multiscale Air Quality (CMAQ) Aerosol Predictions with Impactor Measurements at a Coastal Urban Site. Recently, the aerosol module of the Community Multiscale Air Quality (CMAQ) model was updated to allow inorganic components in coarse mode aerosol to interact dynamically with the gas phase. The new aerosol module enables CMAQ to simulate the replacement of chloride by nitrate in coarse particles in environments where marine air mixes with urban pollution. Previously, we demonstrated that predictions of a box model based on the new aerosol routines agree well with benchmark models for on-shore flow conditions in the Los Angeles area. In the current study, predictions of CMAQ for an 8-km grid domain centered on Tampa Bay, FL were evaluated with impactor measurements at three coastal sites. Predicted size-composition distributions agree very well with the field observations for ammonium and sulfate, which are largely present in fine aerosol modes. Predicted size distributions for sodium, chloride, and nitrate also agree with impactor measurements; however, concentrations for these components are generally too low in the coarse mode. The reason for the low concentrations appears to be an underestimation of sea-salt emissions from the ocean surf zone. New parameterizations of surf zone emissions are currently being implemented in CMAQ to improve coarse aerosol predictions in coastal environments. kelly.james@epa.gov, prakash.bhave@noaa.gov 

The effect of chlorine emissions on ozone predictions in the western United States.. A journal article is being prepared describing the effect of chlorine emissions on ozone predictions in the western United States. Industrial chlorine emissions affected ozone in two geographic areas in the western United States: the Great Salt Lake area and the Oklahoma City area. Chlorine emissions increased the daily maximum 1-hr and 8-hr ozone mixing ratios by up to 10 and 8 ppbv, respectively, near the Great Salt Lake area. However, they also decreased ozone-mixing ratios near the Great Salt Lake area. The largest decrease in daily maximum 1-hr and 8-hr ozone mixing ratios were both 6 ppbv near the Great Salt Lake area. The largest increase in daily maximum 1-hr as well as 8-hr ozone mixing ratios was less than 0.5 ppbv near the Oklahoma City area. sarwar.golam@epa.gov

CB05 Chemical Mechanism Added to the Weather Research and Forecasting with Chemistry (WRF/Chem) Model. Efforts this quarter focused on implementing the updated Carbon Bond (CB05) core chemical mechanism into Version 2.2 of the Weather Research and Forecasting with Chemistry (WRF/Chem) model. Other chemical mechanisms available in WRF/Chem include the Regional Acid Deposition Model version 2 (RADM2), the Regional Atmospheric Chemistry Mechanism (RACM), and the Carbon Bond Mechanism version Z (CBM-Z). CB05, the default chemical mechanism for Version 4.6 of the Community Multiscale Air Quality (CMAQ) model, was added to WRF/Chem via its Kinetic PreProcessor (KPP) and associated WRF/Chem-KPP coupler (WKC) code. Within WRF/Chem, this chemical mechanism with KPP combination is referred to as the CB05_KPP option. Rosenbrock type solvers are currently used with KPP in WRF/Chem, and a framework exists to add other solvers. Routines were written and/or modified to process CMAQ-ready CB05-speciated emissions, chemical initial and boundary conditions, and simple Wesely deposition. The default CB05 idealized initial and boundary conditions were specified to be the same as the defaults currently used by the CMAQ model. During code development for the CB05_KPP option, numerous WRF/Chem test simulations were conducted on both a contiguous United States domain with 36-km horizontal grid spacing and an eastern U.S. domain with 12-km horizontal grid spacing, with plausible results thus far. After additional double-checking of the modified model source code, WRF/Chem with CB05_KPP will be used to simulate the August 2006 retrospective study period and then compared to both observations and CMAQ simulation results. Future improvements to WRF/Chem with CB05_KPP include adding aqueous phase chemistry, coupling the CB05 mechanism to an aerosol scheme, and possibly adding a faster chemical solver. jerry.herwehe@noaa.gov

Oceanic Source of Cl2 within the Community Multiscale Air Quality (CMAQ) model. Division scientists are developing an algorithm that represents an emissions source of Cl2 over oceans. The process is based on studies that observed high concentrations in the marine boundary layer and speculated on a source from sea salt aerosols. It is being incorporated into the Community Multiscale Air Quality (CMAQ) model for simulating atmospheric mercury. hutzell.bill@epa.gov

Pleim-Xiu Land Surface Model, Asymmetric Convective Model version 2 and Surface Layer physics developed for the 2008 release of the Weather, Research and Forecasting Model (WRF Version 3.0.). Work has progressed throughout 2007 and 2008 on the development of a version of the Pleim-Xiu land surface model (PX LSM), the Pleim-Xiu Asymmetric Convective Model version 2 (PX ACM2) boundary layer model, and Pleim surface layer scheme, historically used as physics options in the Fifth-Generation Penn State/National Center for Atmospheric Research mesoscale meteorological model (MM5), for the Weather, Research and Forecasting (WRF) model. The rational for this development is that these physics result in more accurate retrospective meteorological simulations that are used to drive air quality models. For the first quarter of 2008, our efforts have mainly focused on evaluation the new WRF model physics and several other simulations for two journal publications. One journal article presents evaluation of the new planetary boundary layer (PBL) and land surface model (LSM) components in the WRF system with comparisons to other comparable physics options. The other journal article describes a new indirect data assimilation scheme for dynamic adjustment of the deep soil temperature in the PX LSM. After a few additional code changes since last year, the new code for these new physics modules has been provided to the WRF developers at the National Center for Atmospheric Research (NCAR).

Considering the various evaluation angles presented in these studies and the benchmark of the new implementation in WRF with the existing MM5 version and other WRF configurations, the evidence indicates the WRF PX ACM implementation is reasonable, especially during the warmer seasons. The WRF and MM5 versions of the PX LSM are also very much improved because of the new deep soil temperature nudging. However, several ongoing investigations and corresponding improvements are necessary. A snow model to improve the temperature and associated PBL properties over permanent snow areas is being developed. Also, we see evidence that during the winter the WRF PX ACM generates excessive cloud cover at the top of the PBL, which impacts the daytime high temperature in certain areas. The excessive cloudiness needs to be examined in more detail. Finally, it is recommended that model analyses be used more regularly in model evaluation studies, as presented here, since they represent a best guess of the atmosphere considering multiple observations. robert.gilliam@noaa.gov, jonathon.pleim.@noaa.gov

AMD/ERD Collaborative Air-Watershed Research. Robin Dennis and Ellen Cooter of AMD and Chris Knightes and Heather Golden of ERD (Athens, GA) are exploring the linkage of air quality and watershed models. Now that the Community Multiscale Air Quality (CMAQ) modeling system is producing deposition fields for multiple years at fine-spatial scales, the challenge is to see how these fields can be used as atmospheric inputs to watershed models. However, the two types of models usually operate quite differently. The hydrology in watershed models is calibrated with several years of observed precipitation data, while CMAQ relies on precipitation fields generated by numerical weather prediction models, such as the Fifth-Generation Penn State/National Center for Atmospheric Research mesoscale meteorological model (MM5). Thus, the temporal and spatial agreement between modeled MM5 precipitation used to drive CMAQ-estimated deposition and observed precipitation can be poor, and the meteorology using base case and future simulations can differ between the two classes of models. This raises several questions. How sensitive are watershed models to this error? Can watershed models tolerate these errors in a future scenario mode? Can we create greater consistency by using CMAQ inputs for all watershed simulations? As a first step, we have explored with 2001-2003 data 1) using daily observed National Climatic Data Center cooperative station data (as opposed to First Order Meteorological Data) to calibrate the Grid Based Mercury Model (GBMM) for the Cape Fear river basin, 2) driving the calibrated model with 36-km MM5 daily precipitation and mean daily temperature fields, and 3) driving the calibrated model with 12-km MM5 daily precipitation and mean daily temperature fields. Preliminary results for the hydrologic response in the headwaters (Haw River flowing into Jordan Lake) are shown below for the 36-km MM5 and 12-km MM5 simulations for 2001, which is a drier than normal year. Errors in the meteorology appear to be related to timing, spatial coverage, magnitude and suppressed inter-annual variability (MM5 is too wet during the dry summer period). The errors seem worse with the 36-km data, suggesting a distinct preference for 12-km inputs. Further investigation of the simulated precipitation fields indicate that while 24-hour precipitation totals are generally correct, the spatial placement of the events relative to the modeled watershed is poor and can result in runoff spikes. One of our next steps is to explore alternative sources of gridded precipitation data (National Precipitation Analysis), where radar data are merged with site observations to produce higher resolution observations. ellen.cooter@noaa.gov, robin.dennis@noaa.gov

picturepicture

Source Attribution for Atmospheric Deposition of Oxidized Nitrogen to Chesapeake Bay. An upgrade of the Community Multiscale Air Quality (CMAQ) model version 4.5 is now allowing source attribution calculations for oxidized nitrogen (wet and dry) deposition. This was achieved by upgrading the decoupled direct method-3d (DDM-3D) sensitivity approach to include deposition. A first set of CMAQ runs examined the role of six NOx emissions sectors for oxidized nitrogen deposition to the Chesapeake Bay watershed, assuming implementation of the Clean Air Interstate Rule (CAIR) in 2020. The relative role of Electric Generating Units was reduced significantly from 1990 to 2020, according to the CMAQ calculations. Mobile sources (on road) have the highest relative role in 2020, amounting to roughly 25%. Off-road vehicles come in second with roughly 20% responsibility. A second set of CMAQ runs for 2020 CAIR examines the contributions from the six Bay states (DE, MD, NY, PA, VA, WV) for oxidized nitrogen deposition to the Chesapeake Bay watershed. Of the six states, Pennsylvania is responsible for the largest percentage of the oxidized nitrogen, according to the CMAQ calculations, with Virginia a close second. Interestingly, the six Bay states are responsible for 50% of the oxidized nitrogen deposition to the Bay watershed. Long-range transport is still quite important. The CMAQ simulations with DDM-3D allow examination of atmospheric contribution to the coastal waters. robin.dennis@noaa.gov

NOAA in the Carolinas (NinC) 4th Annual Meeting. A Division scientist attended the fourth meeting of NOAA in the Carolinas hosted by the NOAA Laboratory in Beaufort, North Carolina. The Division scientist is also an Air Resources Laboratory representative on the NOAA Southeast and Caribbean Regional Team (SECART). The theme of the NinC meeting was ecosystem-climate connection. The goal was to develop a regional initiative that would fit with the needs of the Carolinas that the NOAA groups could propose for the NOAA planning process. NOAA’s Ecosystem Goal Lead, Steve Murawski, gave an invited presentation. Sea level rise was a key issue that was repeatedly raised, but the group desired to include other facets as well, such as the effects of temperature change on fish and estuarine habitat and increase in range of invasive species, such as the Lionfish. There was interest in EPA’s new Ecosystem Research Program that focuses on ecosystem services and includes a “place-based” study centered on the Coastal Carolinas. There appear to be areas where cooperation between EPA and NOAA would be useful to both organizations. A NinC initiative was not developed as hoped, as the participants ran out of time. There is still interest, however, in doing so. robin.dennis@noaa.gov

Meeting of the Albemarle-Pamlico National Estuary Program (APNEP). A Division scientist participated in the winter meeting of the Albemarle-Pamlico National Estuary Program’s (APNEP) Science and Technical Advisory Committee at East Carolina University. The focus of the technical presentations was on climate change and how the North Carolina coast might or might not adapt to sea level rise and other factors of climate change. In particular, barrier island dynamics was illustrated. The “living” nature of the barrier islands was emphasized and the negative role of real estate property protection was discussed. robin.dennis@noaa.gov

Watershed Deposition Tool Released. A new version of the Watershed Deposition Tool was released via the Division’s webpage (http://www.epa.gov/asmdnerl/Multimedia/depositionMapping.html). An important update in this release was to correct the spheroid used in the Lambert projection to a spherical earth with radius 6370997 meters. This correction caused the Community Multiscale Air Quality (CMAQ) model grid to shift a fraction of a grid cell relative to the underlying map. Another update included adding the display of the grid cell row-column to match the CMAQ convention, where the lower left grid is denoted as (1,1). Also, the blue/red scale used for difference plots was modified to allow users to adjust the extent of the range in the thematic legend. Several changes were made to facilitate use of CMAQ mercury files. The mercury files have been reformatted to allow visualization of all chemical species within the files rather than just mercury. Visualization of chemical species remains the same as before. Also, the default species list has been expanded to include mercury dry, wet, and total deposition. These species are available only in files from the Division’s webpage. donna.schwede@noaa.gov, robin.dennis@noaa.gov

USDA NH3 Project Data Review and Planning Workshop. Several Division scientists met with collaborators from EPA/NRMRL, EPA/OAQPS, EPA/NCEA, NOAA/ATDD, NOAA/ARL, and NCSU to discuss preliminary findings and the status of data processing from the 2007 Lillington, NC, USDA ammonia flux project. The group also discussed a plan for publication and logistics for a 2008 field experiment in Duke Forest, near Chapel Hill, NC. donna.schwede@noaa.gov, jesse.bash@noaa.gov, ellen.cooter@noaa.gov, jon.pleim@noaa.gov

NARSTO Assessment Chapter on Modeling Needs for Multi-Pollutant Accountability. NARSTO is in the midst of an assessment of the technical challenges of implementing accountability within a multi-pollutant air quality management framework. The goal of the NARSTO assessment is to define the technical challenges that must be addressed to be able to implement a multi-pollutant, risk-based approach to air quality management that incorporates accountability as a tool for both measuring the effectiveness of air quality management actions and providing information for improving them. A Division scientist is a co-author of a chapter on air quality modeling needs for the NARSTO assessment. The Division scientist has main responsibility for assessing the air quality model needs with respect to ecosystem health and accountability assessments. His co-author has main responsibility for assessing the air quality model needs for human health and accountability assessments. A meeting of the NARSTO authors was held in Houston, TX on February 28-29, 2008 to address completion of the first drafts of all of the chapters following an internal NARSTO review. The modeling chapter was considered to be complete with no major issues raised. The next step is an external review of the assessment chapters. The NARSTO assessment report is scheduled for completion by January 2009. robin.dennis@noaa.gov

Near-Road Modeling Research.Because of logistical restrictions caused by the unexpected construction of a parking lot at the proposed Las Vegas field study site, the plan for a SF6 tracer study at that site had to be re-evaluated. The newly constructed parking lot severely restricts the ability to deploy SF6 samplers, and the fabric-draped fence surrounding the parking lot will likely cause undesired perturbations in the flow field. NOAA's Field Research Division, who is working with the Division via an EPA Interagency Agreement, has offered instead to host the tracer study at the U.S. Department of Energy reservation near Idaho Falls. This study includes tracer study with both a noise barrier and a "flat land" control case, and for many more sampling periods than would have been possible in Las Vegas. The plan now is to release SF6 from a ~150 m perforated pipe and use a sampling array (of up to 30 samplers) to characterize ground-level concentrations downwind of a noise barrier and a roadway. In addition, the tracer study will be extended to a nearby roadcut, if sufficient samples are available from the noise barrier site. The idealized site near Idaho Falls will facilitate development of an improved line source algorithm for integration into dispersion models such as the AMS/EPA Regulatory Model (AERMOD). thomas.pierce@noaa.gov, vlad.isakov@noaa.gov, steven.perry@noaa.gov, david.heist@noaa.gov

Wildland-Fire Emissions. Working with EPA’s Office of Air Quality Planning and Standards (OAQPS), a multi-year fire inventory has been eveloped using satellite and ground-based information. This represents the first successful effort to incorporate satellite imagery into EPA’s National Emission Inventory. The fire inventory, which is from August 2002 to December 2006, has been derived from the NOAA’s Hazard Mapping System (HMS) fire detection product. Biomass burning emission estimates have been estimated using the US Forest Service CONSUMEv3.0 consumption model and the Fuel Characteristic Classification System (FCCS) fuel-loading database. CONSUMEv3.0 reflects an improved understanding of fuel consumption and emissions in wildland fire throughout major fuel types in the United States. The annual variability of estimated burn area and emissions using this approach is shown below. george.pouliot@noaa.gov, pace.tom@epa.gov

 

 

All non-agriculture and non-wildfires (includes prescribed burning and other satellite detects)

Year

Acres

Fuel Consumed

Tons Fuel/Acre

PM2.5

lb PM2.5/Ac burned

lb PM2.5/Tfuel

2002 (Aug-Dec)

1,255,227

16,143,004

12.86062

169,770

271

21

2003

5,500,480

65,190,731

11.85183

704,310

256

22

2004

6,928,393

70,681,993

10.20179

731,402

211

21

2005

8,632,472

87,230,420

10.10492

919,423

213

21

2006

8,454,730

87,974,863

10.4054

920,593

218

21

 

All wildland Fires (lower 48 states)

 

Acres

Fuel Consumed

Tons Fuel/Acre

PM2.5

lb PM2.5/Ac burned

lb PM2.5/Tfuel

2002
(Aug-Dec)

691,081

25,020,611

36.20501

283,743

821

23

2003

2,685,580

52,359,161

19.49641

576,032

429

22

2004

900,594

15,565,762

17.28388

169,870

377

22

2005

1,770,942

16,496,445

9.315068

177,738

201

22

2006

3,859,114

66,698,110

17.28327

749,422

388

22

Climate Impacts on Regional Air Quality (CIRAQ) Future Year Emissions. Future year emissions for four months in 2048 are being generated using market allocation (MARKAL) model factors for combustion sources, and population projections or future demand curves as surrogates for other source categories. The MARKAL factors were derived from work from EPA’s National Risk Management Laboratory, who has been working on updating MARKAL from its origins with the International Energy Agency to a nine-region United States model. Population change is addressed under the Integrated Climate and Land Use Scenarios/Spatially Explicit Regional Growth Model (ICLUS/SERGOM) project on geographical changes in population change by the EPA National Center for Environmental Assessment and Colorado State University.

Growth factors reflecting the International Panel on Climate Change (IPCC) A1B and A2 scenarios are being applied to anthropogenic emissions for selected future year months between 2048 and 2052, using the EPA 2001ah emission-modeling inventory as a base case. Biogenic emissions were previously modeled for the same future period using downscaled future regional meteorology. The objective of this work is to determine the overall and regional relative importance of the differences in emission scenarios with respect to each other as well as the base emissions, and in particular, whether the differences in emissions are significant as emissions or create significant differences in the Community Multiscale Air Quality (CMAQ) model output relative to changes in biogenic emissions driven by meteorology. william.benjey@noaa.gov

Comparative Analyses of Modeled and Observed Ozone Vertical Profiles An effort has begun to investigate ozone concentrations and vertical structure within and above the daytime planetary boundary layer (PBL) from model simulation results and measurements aloft. High-resolution vertical ozone profiles in a data set obtained by a research aircraft, operated by the University of Maryland’s Department of Atmospheric & Oceanic Science, are being matched up with modeled ozone profiles generated by the Community Multiscale Air Quality (CMAQ) model. Vertical aircraft spirals from near the surface to about 3000 m were performed during the mid-morning and mid-afternoon periods at numerous locations in the mid-Atlantic and New England states during an experimental field study from early June to mid-August 2002. The modeled profiles, generated in 10 vertical layers below 3000 m, are paired in space and time with each observed vertical profile. The comparisons will also provide insight into model differences since simulations applied two photochemical mechanisms (CB4 (Carbon Bond 4), updated CB05), and two different vertical mixing schemes (vertical mixing coefficient (Kv), asymmetric convective model (ACM2)). An additional model simulation is being performed with more vertical layers which will provide higher vertical resolution within the PBL. It is anticipated that these analyses will reveal the extent of similarity in the vertical structure and magnitude of ozone between the model and measurements, and also provide valuable information about the possible reasons for model underestimation of surface maximum ozone values during episodes from this summer season.james.godowitch@noaa.gov

Future Climate and Air Quality: Phase I Completion of the Climate Impacts on Regional Air Quality (CIRAQ). Air quality is known to be sensitive to meteorology. Air quality management decisions are presently made assuming current climatological conditions, yet controls can be implemented over several decades. If future climate differs substantially from present climate, there is an additional layer of uncertainty when considering future controls scenarios. To assess the potential impact of one climate change scenario on future air quality, outputs from a global scale climate and chemistry model were used as boundary conditions for regional scale meteorology and air quality simulations using the Fifth-Generation Penn State/National Center for Atmospheric Research mesoscale meteorological model (MM5) and the Community Multiscale Air Quality (CMAQ) model. Results indicate that climate change could contribute an additional 2-5 ppb to ozone concentrations in the eastern U.S. and Texas, while particulate matter concentrations are decreased. A manuscript describing this work has been accepted for publication in the Journal of Geophysical Research. chris.nolte@noaa.gov, alice.gilliland@noaa.gov

Future Climate and Air Quality: Projections of U.S. Anthropogenic Emissions at 2050 for Phase II of Climate Impacts on Regional Air Quality (CIRAQ). In collaboration with EPA’s National Risk Management Research Laboratory (NRMRL), the market allocation (MARKAL) energy systems model is used to project the growth of electric power demands and emissions from power plants. These emission factors are then used as inputs to the Sparse Matrix Operator Kernel Emissions (SMOKE) emissions processor, which generates emissions inputs necessary to run the Community Multiscale Air Quality (CMAQ) model. Emissions have been generated for four months (one from each season) and compared to present emissions levels. Initial quality assurance efforts indicate that the projected emissions are consistent with current levels and with expected decreases in nitrogen oxides (NOx) and sulfur dioxide (SO2) and increases in carbon monoxide (CO). Projected emissions of primary particulate matter, however, are 50% higher than current, an overestimate which is likely due to using population as a surrogate for some emissions sectors. Previous work examining year 2050 air quality in the U.S. assumed that anthropogenic emissions remained at 2001 levels, in order to isolate the effect of climate change. Once these emissions projections are finalized, they will be used with the meteorology derived from the future climate scenario to investigate the combined effect of climate change and changing emissions on future U.S. air quality. chris.nolte@noaa.gov, william.benjey@noaa.gov.

The Community Multiscale Air Quality (CMAQ) model v4.7: Evaluation of Incremental Tests. Analyses continue on the incremental testing of substantial changes for the Community Multiscale Air Quality (CMAQ) model v4.7. Simulations have been completed for several new updates including (a) how well changes in cloud cover and precipitation when shifting from the Fifth-Generation Penn State-National Center for Atmospheric Research Mesoscale Model (MM5) to the Weather Research and Forecasting (WRF) correlate to the corresponding changes in sulfate and nitrate values between these two runs, and (b) which secondary organic aerosol (SOA) components in the updated chemistry module are most driving the changes seen in organic carbonaceous aerosol predictions. kristen.foley@noaa.gov

RESEARCH INITIATIVES

Demonstrating Air Quality Forecast Evaluation Techniques using Metropolitan Statistical Areas and Comparing Air Quality Index Verification to Heat Index verification. Several Division scientists are collaborating to demonstrate new techniques to evaluate gridded air quality forecast guidance from the National Air Quality Forecast Capability (NAQFC) using the Community Multiscale Air Quality (CMAQ) Modeling System. In this study, comparisons are made between various discrete and categorical methods of evaluating guidance from the NAQFC and from local air quality forecasters against the National Ambient Air Quality Standard (NAAQS) for ozone, as measured by monitoring networks in urban areas that are in violation of the NAAQS.

Also as part of this study, a new evaluation concept is introduced to validate air quality model performance against the quality index (AQI) that is observed within a metropolitan statistical area (MSA) in order to better align with the Environmental Protection Agency’s guidelines for determining urban regions that are in violation of the NAAQS. In addition, using the AQI for air quality evaluation is shown to be analogous to using metrics such as the heat index for near-surface meteorological evaluation. This initiative further suggests that the AQI and heat index have a symbiotic relationship in the summer season (when ozone is the primary pollutant), and it is feasible to combine the elements of both indices to form the foundation for a broader ambient exposure health index.

These concepts are introduced and demonstrated using examples from the summer 2007 ozone forecast season and nine MSAs throughout the United States. An in-depth study of the Charlotte MSA illustrates that the forecast guidance from the NAQFC is reliable for daily forecasts of AQI and heat index; local forecasters can further refine the air quality forecasts for the MSA of interest. The details of this research study are being drafted in a manuscript that will be submitted for publication within the next quarter. brian.eder@noaa.gov, kang.daiwen@epa.gov, yu.shaocai@epa.gov, tanya.otte@noaa.gov, rohit.mathur@noaa.gov, kenneth.schere@noaa.gov, st.rao@noaa.gov

Using Satellite-derived Cloud Products to Improve Ozone Predictions with the Community Multiscale Air Quality (CMAQ) Modeling System. Division scientists are exploring the use of satellite-derived cloud products in the Community Multiscale Air Quality (CMAQ) Modeling System to improve ozone predictions. The original capability was developed under cooperative agreement by researchers at University of Alabama at Huntsville (UAH). The UAH method uses gridded visible imagery from the Geostationary Operational Environmental Satellite for the Eastern United States (GOES-East) to replace model-generated fields of cloud top and bottom and create a new field of cloud transmissivity that can be used in the photolysis calculations. When and where satellite imagery is unavailable in the simulation period and domain, CMAQ reverts to using cloud fields that are derived from the meteorological model.

Initial model simulations with the UAH methodology were conducted using the 12‑km Eastern United States domain for August 2006. The goal is to work with UAH and the Community Modeling Analysis System (CMAS) Center to release a prototype of the satellite processing as part of the September 2008 community release of CMAQ. shawn.roselle@noaa.gov, tanya.otte@noaa.gov

Future Climate and Air Quality: Developing Additional Future Climate Simulations. Our previous simulations of future air quality used a climate simulation from the Goddard Institute for Space Studies (GISS) general circulation model (GCM), model version 2’. GISS 2’ has a relatively coarse spatial resolution (4° latitude ´ 5° longitude, with only 9 vertical layers). We are exploring the possibility of using alternate GCMs to drive future regional climate and air quality models.; The Geophysical Fluid Dynamics Laboratory (GFDL) AM2 global atmospheric model (2° latitude ´ 2.5° longitude, with 24 vertical layers) has been downloaded to begin testing for this purpose. The code has been successfully compiled and run for a one-day test simulation.  Work is underway to develop a method to downscale these outputs using the Weather Research and Forecasting (WRF) model. chris.nolte@noaa.gov.

COMPUTER INFRASTRUCTURE SUPPORT

Model Evaluation Support: Data Processing. Data sets were assembled for the dynamic and probabilistic evaluation of the Community Multiscale Air Quality (CMAQ) model.  This data are used to compare Clean Air Status and Trends network (CASTNET) and Air Quality Systems (AQS) observations to CMAQ model results. Modeling results for summers 2002 through 2006 are included in this dataset of CMAQ simulations. steve.howard@noaa.gov

Data processing support for the New York AMI project. Generated and assembled Air Quality Systems (AQS), Clean Air Status and Trends network (CASTNET), national Air Pollution Surveillance Network of Canada (NAPS), and the Community Multiscale Air Quality (CMAQ) model modeled data needed to for the Hierarchical Bayesian data fusion and air quality characterization. The data from these runs are needed to compare different techniques for merging modeled and observed data sets. steve.howard@noaa.gov

CONFERENCES, WORKSHOPS, AND PRESENTATIONS

88th Annual Meeting of the American Meteorological Society, New Orleans, Louisiana, January 21-24, 2008.

Presentations included:
Bash, J.O., Bi-directional surface exchange of Hg in CMAQ. Joint Session of the 15th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA and 10th Conference on Atmospheric Chemistry, New Orleans, Louisiana, American Meteorological Society, January 23, 2008.

Eder, B. D. Kang, R. Mathur, J. Pleim, and S. Yu. An evaluation of the National Air Quality Forecast capability for the summer of 2007. Joint Session of the 15th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA and 10th Conference on Atmospheric Chemistry, New Orleans, Louisiana, American Meteorological Society, January 23, 2008.

Lin, H.-mu., R. Mathur, S. McKeen, P. Lee, and J. McQueen. Application of potential vorticity in a comprehensive Air Quality Forecast Model for ozone. Joint Session of the 15th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA and 10th Conference on Atmospheric Chemistry, New Orleans, Louisiana, American Meteorological Society, January 23, 2008.

Otte, T. L. The impact of nudging in the meteorological model for retrospective air quality simulations. Joint Session of the 15th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA and 10th Conference on Atmospheric Chemistry, New Orleans, Louisiana, American Meteorological Society, January 23, 2008.

Otte, T. L. A nudging strategy for mesobeta-scale WRF simulations suitable for retrospective air quality modeling: Preliminary results. Joint Session of the 15th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA and 10th Conference on Atmospheric Chemistry, New Orleans, Louisiana, American Meteorological Society, January 23, 2008.

Great Basin Mercury Working Group Meeting, Reno, Nevada, January 16-18, 2008. Russell Bullock attended this meeting and gave a presentation entitled, “Model evaluation using monitoring data.” The meeting provided state and regional participants with an opportunity to hear about the latest mercury research and to discuss how to incorporate that research into their ongoing program and policymaking efforts in a coordinated way.

Institute of Tropical and Marine Meteorology, China Meteorological Administration (CMA), Guangzhou, and the School of Environmental Science and Engineering, South China University of Technology, March 3-8, 2008. David Wong was invited to visit these two institutions. He assisted the scientists and students with the setup of the Community Multiscale Air Quality model (CMAQ), and its associated processes, as well as vital components MPI and netCDF. CMAQ will be used to study air quality in the Pearl River delta region.

Tropospheric Ozone-Monitoring Instrument Workshop.A Rob Pinder traveled to Utrecht, The Netherlands as an invited speaker in the Tropospheric Ozone-Monitoring Instrument Workshop and presented work titled “Use of space-based tropospheric NO2 observations in regional air quality modeling.” The purpose of the workshop was to get feedback from users of the space-based atmospheric trace gas measurements in order to inform the next generation of satellite instruments. Topics included relevant spectral ranges, spatial resolution, and orbital configurations. This workshop was hosted by the Royal Netherlands Meteorological Institute (KNMI) and was held at their headquarters in Utrecht (DeBilt) during March 5-6, 2008.

PUBLICATIONS

Published Paper

Dennis, R.L., P.V. Bhave, and R.W. Pinder. Observable Indicators of the Sensitivity of PM2.5 Nitrate to Emission Reductions, Part II: Sensitivity to Errors in Total Ammonia and Total Nitrate of the CMAQ-Predicted Nonlinear Effect of SO2 Emission Reductions, Atmospheric Environment, 42: 1287 – 1300 (2008).

Gego, E., S. Porter, A Gilliland, C. Hogrefe, J. Godowitch, and S. T. Rao. Modeling analysis of the effects of changes in nitrogen oxides emission from the electric power sector on ozone levels in the eastern United States. Journal of Air & Waste Management Association. 58(4): 580-588

Godowitch, J.M., A.B. Gilliland, R.R. Draxler, S.T. Rao, 2008. Modeling assessment of point source NOx emission reductions on ozone air quality in the eastern United States. Atmospheric Environment, 42, 87-100.

Mathur, R., S. Yu, D. Kang, and K. Schere, Assessment of the Winter-time Performance of Developmental Particulate Matter Forecasts with the Eta-CMAQ Modeling System, Journal of Geophysical Research, 113, D02303, doi:10.1029/2007JD008580, 2008.

Napelenok, S.L., D. S. Cohan, M.T. Odman, and S. Tonse. Extension and evaluation of sensitivity analysis capabilities in a photochemical model.  Environmental Modeling and Software. 23(8):994-999

Pinder, R.W., R.L. Dennis, and P.V. Bhave. Observable Indicators of the Sensitivity of PM2.5 Nitrate to Emission Reductions, Part I: Derivation of the Adjusted Gas Ratio and Applicability at Regulatory-Relevant Time Scales, Atmospheric Environment, 42: 1275 – 1286 (2008).

Paper in Press

Appel, K.W., P.V. Bhave, A.B. Gilliland, G. Sarwar, and S.J. Roselle. Evaluation of the Community Multiscale Air Quality (CMAQ) Model Version 4.5: Sensitivities Impacting Model Performance; Part II – Particulate Matter, Atmospheric Environment, and Web publication date: March 29, 2008.

Gilliland, A.B., C. Hogrefe, R.W. Pinder, J.M. Godowitch, K.L. Foley, and S.T. Rao, Dynamic Evaluation of Regional Air Quality Models: Assessing Changes in O3 Stemming from Changes in Emissions and Meteorology, Atmospheric Environment,doi:10.1016/j.atmosenv.2008.02.018, 2008.

Luecken, D.J. and A.J. Cimorelli, “Co-dependencies of reactive Air Toxic and criteria pollutants on emission reductions,” J. of Air and Waste Management Assoc, Accepted for publication 2/1/08.

Napelenok, S. L., R. Pinder, A. B. Gilliland, and R. V. Martin. A method of evaluating spatially resolved NO2 emissions using Kalman filter inversion, direct sensitivities, and space-based NO2 observations. Atmospheric Chemistry and Physics.

Nolte, C.G., P.V. Bhave, J.R. Arnold, R.L. Dennis, K.M. Zhang, and A.S. Wexler. Modeling of Urban and Regional Aerosols – Application of the CMAQ-UCD Aerosol Model to Tampa, a Coastal Urban Site, Atmospheric Environment, Web publication date: January 5, 2008.

Yu, S., R. Mathur, K. Schere, D. Kang, J. Pleim, J. Young, D. Tong, G. Pouliot, S. McKeen, and S.T. Rao, Evaluation of real-time PM2.5 forecasts and process analysis of PM2.5 formation over the eastern U.S. using the Eta-CMAQ forecast model during the 2004 ICARTT study, Journal of Geophysical Research-Atmospheres, doi:10.1029/2007JD009226,  in press, 2008.

Submitted Papers

Bullock, O.R, Jr., D. Atkinson, T. Braverman, K. Civerolo, A. Dastoor, D. Davignon, J. Ku, K. Lohman, T. C. Myers, R. J. Park, C. Seigneur, N. E. Selin, G. Sistla, K. Vijayaraghavan. The North American Mercury Model Intercomparison Study (NAMMIS). Part 1: Study description and model-to-model comparisons, submitted to Journal of Geophysical Research (JGR).

Bullock, O.R, Jr., D. Atkinson, T. Braverman, K. Civerolo, A. Dastoor, D. Davignon, J. Ku, K. Lohman, T. C. Myers, R. J. Park, C. Seigneur, N. E. Selin, G. Sistla, K. Vijayaraghavan. The North American Mercury Model Intercomparison Study (NAMMIS).  Part 2: Comparisons to observed wet deposition of mercury, submitted to Journal of Geophysical Research (JGR).

Godowitch, J.M., C. Hogrefe, S.T. Rao. Diagnostic analyses of a regional air quality model: Changes in modeled processes affecting ozone and chemical-transport indicators from NOx point source emission reductions. Journal of Geophysical Research – Atmospheres.

Dimitriades, B., and D. Luecken, “Ozone air quality management approaches and methods: past, present, and future,” Invited paper submitted to Atmospheric Environment 3/21/08.

Mathur, R., Estimating the Impact of the 2004 Alaskan Forest Fires on Episodic Particulate Matter Pollution over the Eastern United States through Assimilation of Satellite Derived Aerosol Optical Depth in a Regional Air Quality Model, Journal of Geophysical Research-Atmospheres, revisions submitted, 2008.

Pinder, R.W., A.B. Gilliland, and R.L. Dennis, The Environmental Impact of Atmospheric NH3 Emissions under Present and Future Conditions in the Eastern United States, Geophysical. Research Letter,

Papers in NOAA Review

Pinder, R. W., R. C. Gilliam, W. Appel, S. L. Napelenok, and A. B. Gilliland.  Efficient probabilistic estimates of ozone concentration using an ensemble of model configurations and direct sensitivity calculations. Environmental Science and Technology.
Swall, J.L., and K. M. Foley. The impact of incommensurability on model evaluation strategies: Moving beyond the comparison of matched observations and model grid cells. Journal TBD

Atmospheric Modeling

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