ACCESS NUMBER: 31071 

STUDY TITLE: Development of the Next Generation Air Quality Models for Outer Continental Shelf 

(OCS) Applications. 

REPORT TITLE: Development of the Next Generation Air Quality Models for Outer Continental Shelf 

(OCS) Applications. 

CONTRACT NUMBER(S): 1435-01-01-CT-31071. 

SPONSORING OCS REGION: MMS Headquarters. 

APPLICABLE PLANNING AREAS(S): National. 

FISCAL YEARS(S) OF PROJECT FUNDING: 2002; 2003; 2004; 2005; 2006. 

COMPLETION DATE OF REPORT: March, 2006. 

COSTS(S): FY 2002: $51,698; FY 2003: $97,771; FY 2004: $97,951; FY 2005: $105,332; FY 2006: 

$32,655; CUMULATIVE PROJECT COST: $385,407. 

PROJECT MANAGER(S): J. Scire. 

AFFILIATION: Earth Tech, Inc. 

ADDRESS: 196 Baker Avenue, Concord, Massachusetts 01742. 

PRINCIPAL INVESTIGATOR(S)*: J. Scire, D. Strimaitis, F. Robe, M. Phadnis, J. Popovic 

KEY WORDS: Air quality modeling; meteorology; overwater boundary layer; CALPUFF; standard 

meteorological dataset; modeling software. 

BACKGROUND: As a result of significant advances in the scientific understanding of dispersion 

modeling over the last couple of decades, the MMS has identified a need to develop a model for 

application to emission sources on the Outer Continental Shelf (OCS) that incorporates, to the extent 

feasible, the most current knowledge and is versatile enough to be used in short-range as well as 

long-range applications. The goal of this study was to enhance an existing air quality model for 

applications involving overwater transport and coastal interaction effects.

OBJECTIVES: (1) To perform a comprehensive review of existing models and to evaluate their 

applicability to offshore applications based on current knowledge of boundary layer and atmospheric 

dispersion in ocean and shoreline environments; (2) To revise or enhance an existing air quality 

model to make it suitable for offshore and coastal applications; (3) To develop a software package 

that includes the needed meteorological pre-processors, meteorological model, air quality model, 

source codes, test cases, and user’s guide; (4) To carry out sensitivity testing and evaluate model 

performance against available tracer data.

DESCRIPTION: The new model for OCS applications is an extensively updated version of the 

CALPUFF (Scire et al., 2000a, 2000b) modeling system. Individual components had been compared 

with other modeling approaches in OCD (DiCristofaro and Hanna, 1989), AERMOD (Cimorelli et al., 

2002), and SCIPUFF (EPRI, 2000). These comparisons included the model formulation equations as 

well as sensitivity tests performed on individual modules (e.g., boundary layer parameters, turbulence 

profiles over water, plume spread formulations). 

Enhancements introduced into the CALPUFF modeling system included new technical features 

parameterizing the overwater boundary layer and coastal effects on dispersion, ease-of-use features 
ACCESS NUMBER: 31071 

in the graphical user interface and new utility programs, and a standard one-year (2003) 

preprocessed dataset for the Gulf of Mexico area. The performance evaluation of the new model led 

to the formulation of a turbulence advection mechanism in CALPUFF when it was discovered that 

advected turbulence is an important feature of the dispersion documented in the Oresund 

experiments, when releases were made at the coast during off-shore flow. 

The major new features in CALMET include an option to use the Coupled Ocean Atmosphere 

Response Experiment (COARE) overwater flux model (Fairall et al., 2002); a convective overwater 

boundary layer height computed for conditions of positive surface heat flux; a new convective mixing 

height parameterization (Batchvarova and Gryning, 1991,1994) option; and an automatic height 

adjustment of surface winds from anemometer height to the middle of CALMET Layer 1. 

CALPUFF has been modified to include new features for building downwash at elevated offshore 

platform structures with an open area between the water surface and the raised structure; an option 

to use AERMOD turbulence profiles; an option to accept the AERMET version of SURFACE and 

PROFILE meteorological data files; and an adjustment for turbulence advection from regions of larger 

turbulence velocity into regions of smaller turbulence velocity. 

The CALPUFF graphical user interface was extensively revised and enhanced, including new 

processors for buoy data and NCEP model output; a new utility for extracting a user-defined subset of 

data from the standard 2003 Gulf of Mexico dataset; extensively revised and enhanced graphical 

display modules to allow animations, contour plots, vector plots and other types of graphical displays. 

The standard Gulf of Mexico meteorological and ozone dataset was prepared, which includes one full 

year (2003) of gridded prognostic meteorological output fields from the Rapid Update Cycle (RUC) 

mesoscale weather model covering the MMS Gulf of Mexico domain, data for 13 buoy stations, 21 

upper stations, 230 hourly surface meteorological stations, 271 precipitation stations, 201 ozone 

monitoring stations and terrain and land use data for the modeling domain. 

SIGNIFICANT CONCLUSIONS: Sensitivity tests and a model evaluation have shown that the 

COARE overwater flux model results in improved model performance over the OCD model and 

previous CALPUFF formulations. The standard COARE option performed as well with these datasets 

as more complex COARE options including shallow water adjustments or a wave model. A minimum 

value of the lateral turbulence velocity of water (0.37 m/s) different from the overland value (0.5 m/s) 

results in improved model performance. Turbulence advection was found to be important in a coastal 

application in offshore flow situations with a coastal source. AERMOD turbulence profiles performed 

as well or slightly better than the original turbulence-based parameterization in CALPUFF. 

Consideration of the convective mixing height over water was determined to provide important 

improvements in mixing height estimates over water. The Batchvarova-Gryning convective mixing 

height model showed improved performance over the Maul-Carson method in the evaluation 

datasets. 

STUDY RESULTS: A new, technically-enhanced version of the CALPUFF modeling system has 

been developed and provided to the MMS. A model evaluation study with five overwater and coastal 

datasets has shown substantial improvement of the new model over the Offshore and Coastal 

Dispersion (OCD) steady-state model and previous versions of CALPUFF for these types of 

applications. Significant enhancements and new modules in the Graphical User Interfaces and the 

development of a standard modeling dataset for the year 2003 have made the modeling platform 

significantly easier to use. 
ACCESS NUMBER: 31071

STUDY PRODUCT(S): Scire, J.S., Strimaitis, D.G., Robe, F.R., Popovic, J.M. and Phadnis, M.J., 

2006. Development of the Next Generation Air Quality Models for Outer Continental Shelf (OCS) 

Applications. Final Report: Volume 1. MMS Final Report. Contract 1435-01-01-CT-31071, U.S. 

Department of the Interior, Minerals Management Service, Herndon, Virginia. 131 pp. 

Robe, F.R., Strimaitis, D.G., Scire, J.S., Popovic, J.M. and Phadnis, M.J., 2006. Development of the 

Next Generation Air Quality Models for Outer Continental Shelf (OCS) Applications. Final Report: 

Volume 2. CALPUFF Users Guide. (CALMET and Preprocessors). 348 pp. 

Strimaitis, D.G., Scire, J.S., Robe, F.R., Popovic, J.M. and Phadnis, M.J., 2006. Development of the 

Next Generation Air Quality Models for Outer Continental Shelf (OCS) Applications. Final Report: 

Volume 3. CALPUFF Users Guide. (CALPUFF and Postprocessors). 384 pp. 

Standard CALMET/CALPUFF Dataset for 2003 including RUC data, surface observations, upper air 

observations, precipitation data, buoy data and geophysical data for the Gulf of Mexico area. 

CALPUFF Modeling System including model codes, graphical user interfaces and test case datasets. 

* P.I.’S affiliation may be different than that listed for Project Manager(s). 

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 MMS 2003 standard CALPUFF dataset showing the modeling domain (yellow 

 border), RUC tiled data and surface meteorological station locations.