# Guidance on the Use of the Mesoscale Model Interface Program (MMIF) for AERMOD ApplicationsEPA

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Guidance on the Use of the Mesoscale Model Interface Program (MMIF) for AERMOD Applications

U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Air Quality Assessment Division Air Quality Modeling Group Research Triangle Park, North Carolinaii Preface

This document provides guidance on the use of prognostic meteorological data and the Mesoscale Model Interface Program (MMIF) in AERMOD. Included in this document are descriptions of the inputs to MMIF and recommendations on using MMIF output in AERMOD

.iii Acknowledgements

MMIF was developed by Environ International Corporation under EPA contract number EP

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- 102, work assignment s 2

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- 1 . The MMIF user’s guide was developed by Bart Brashers and Chris Emery of Environ. This guidance document was developed by the Air Quality Mo deling Group of the Air Quality Assessment Division of the Office of Air Quality Planning and Standa rds in collaboration with representatives of EPA Regions 5, 7, and 8.iv Contents
Preface

................................ ................................ ................................ ................................ ............. ii

Acknowledgements

................................ ................................ ................................ ........................ iii

Tables

................................ ................................ ................................ ................................ .............. v

1. Introduction

................................ ................................ ................................ ................................ . 1

2. Guidance on using prognostic meteorological data fo r use in AERMOD

................................ .. 1

2.1 Number of years to model

................................ ................................ ................................ ..... 2

2.2 Prognostic model options

................................ ................................ ................................ ...... 2

2.2.1 Development of meteorological fields

................................ ................................ ........... 2

2.3 Model output quality assurance

................................ ................................ ............................ 2

2.3.1 Operational evaluation

................................ ................................ ................................ ... 2

3. Guidance on running MMIF for AERMOD

................................ ................................ ............... 3

3.1 MMIF Input File

................................ ................................ ................................ ................... 3

3.2 Recommended options for selected keywords

................................ ................................ ...... 6

3.2.1 Outputs

................................ ................................ ................................ ........................... 6

3.2.1.1 AERMET

................................ ................................ ................................ ................ 6

3.2.1.2 AERMOD

................................ ................................ ................................ ............... 7

3.2.2 Output layers and heights

................................ ................................ ............................... 7

3.2.3 Grid cells to process

................................ ................................ ................................ ....... 7

3.3 Surface characteristics

................................ ................................ ................................ .......... 7

3.4 Trea tment of low winds

................................ ................................ ................................ ........ 8

3.5 Post

- processing of outputs

................................ ................................ ................................ .... 8

4. References

................................ ................................ ................................ ................................ . 10v Tables

Table 1

. AERMET/AERMOD keywords in MMIF input file. .......................................................41

1. Introduction

The guidance discussed in this document are recommendations for running the Mesoscale Model Interface ( MMIF ) program 1 to generate inputs for AERMET and AERMOD. In this guidance document, when references are made to running MMIF for AERMOD, it should be inferred that this refers to AERMET as well. For regulatory applications, MMIF should be run to generate AERMET inputs as stated in section 8.4.2(a) and 8.4.5.1(b) of the proposed revisions to EPA’s Guideline on Air Quality Models (U.S. EPA, 2015) 2 . Regulatory applications that do not follow these sections of Appendix W will need to consult with the appropriate reviewing a uthority and guidelines outlined in section 3.2 of Appendix W. Given that Appendix W and specific EPA modeling guidance are often cited in relation to other non

- regulatory modeling applications, such as air quality analysis and disclosure purposes under NE PA, the approach presented in this guidance document for regulatory applications also has relevance to these non

- regulatory applications. While MMIF can process data for other air quality models (e.g., CALPUFF and SCICHEM), the emphasis in this guidance is for AERMOD applications conducted for regulatory purposes.

This guidance document will summarize some of the inputs needed for AERMET and AERMOD MMIF processing, but will refer to the MMIF User’s Guide (Environ, 2014) for more

details. MMIF users are s trongly encouraged to read this user’s guide to obtain specific details on running MMIF.

2. Guidance on using prognostic meteorological data for use in AERMOD

In general, air quality modeling applications rely on the use of meteorological grid models. These models are used to more accurately simulate atmospheric processes (e.g., temperature, wind speed and direction, etc.) across a specific area. In retrospective simulations (i.e., modeling past events), the blending of observed data with computed field s yields results that are bound by ground truth.

There are several meteorological grid models that can be used to develop inputs for air quality models. The most commonly used by EPA and the modeling community is the Weather Research and Forecasting (WRF) model (Skamarock et al., 2008) 3

, which is supported across a broad community and provides state

- of

- the

- science parameterizations of the atmosphere. Additionally, the Fifth Generation Penn State/NCAR Mesoscale Model (MM5) (Grell et al.,

1 http://www.epa.gov/ttn/scram/dispersion_related.htm#mmif

2 Hereafter, the Guideline will be referred to as Appendix W.

3 http://www.wrf

- model.org/index.php2

1994) is capable of generating the necessary meteorological inputs to air quality models ; however, its development and maintenance is no longer supported

.

2.1 Number of years to model

As discussed in Section 8.4.2(e) of the proposed Appendix W, at least three consecutive years are required to be modeled in the prognostic model. The most recent three years are preferred and the prognostic model domain or selected grid cells should be representative of the domain.

See Section 8.4.b of the proposed Appendix W for more details about representativeness of meteorological data.

2.2 Prognostic model options

2.2.1 Development of meteorological fields

Section 2.6 of the Modeling Guidance for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze (U.S.EPA, 2014) recommends approaches for developing prognostic meteorological data. While specific recommendations for model options are not provided, this guidance discusses the proper steps to ensure the data are represen tative of the air quality model domain. The reader is referred to U.S. EPA (2014) for details on the development of the meteorological fields.

2.3 Model output quality assurance

2.3.1 Operational evaluation

Demonstration of the adequacy of prognostic me teorological fields can be established through appropriate diagnostic and statistical performance evaluations consistent with recommendations provided in the appropriate EPA guidance. A quantitative, statistical, and graphical analysis of the prognostic da ta should be completed, comparing the data to available NWS automated surface observation station (ASOS) data, as well as operational profiler data (if available), pairing both in space and time. This analysis should be completed for all years (at least th ree) of prognostic meteorological data to be used in the air quality simulations. Since the spatial scope of each variable could be different, representativeness should be judged for each variable separately as discussed in Section 8.4.2(b) of the proposed Appendix W (U.S. EPA, 2015a) . For example, for a variable such as wind direction, the data should ideally be collected near plume height to be adequately representative; especially for sources located in complex terrain, whereas, for a variable such as te mperature, data from a station several kilometers away from the source may be considered to be adequately representative. The grid resolution of the prognostic3

meteorological data should also be considered and evaluated appropriately, particularly for proj ects involving complex terrain. Several software packages are available for use in completing this evaluation (e.g., AMET (Appel et al., 2011) and METSTAT ( http://www.camx.com/download/support

- software.aspx )). The adequacy of output from the meteorological models is contingent upon the concurrence with the appropriate reviewing

authorities as defined in s ection 8.4. 5 .2 (a) of the proposed Appendix W

.

3. Guidance on running MMIF for AERMOD

Much of the guidance presented here follows the MMIF user’s guide (E nviron, 2014) . Relevant information from the user’s guide is summarized in this guidance for convenience but the user is strongly encouraged to read the full MMIF user’s guide before attempting to run MMIF. Section 3.1 below discusses the inputs to MMIF, Section 3.2 discusses the relevant options to AERMOD and grid cells to process. Section 3.3 discusses the use of surface characteristics outside of MMIF and Section 3.4 discusses post

- processing the output from MMIF needed for input into

AERMOD.

3.1 MMI F Input File

MMIF processing is done via a control file with keywords to denote inputs, processing options, and outputs. Table 1 lists the keywords used to run MMIF for AERMET and AERMOD input. A sample control file that illustrates all of the keywords can be generated for MMIF by typing
“mmif

– sample” at the command prompt. See Section 4.2 of the User’s Guide (Environ, 2014)

for more information.4

Table 1 . AERMET/AERMOD keywords in MMIF input file.

Keyword Description Syntax
Start Date and time (Local Standard Time) to start

processing Start YYYY MM DD HH
Or
Start YYYYMMDDHH

Or
Start YYYY

- MM

DD_HH:mm:ss Stop Date and time (LST) to stop processing Stop YYYY MM DD HH
Or Stop YYYYMMDDHH

Or Stop YYYY

- MM

DD_HH:mm:ss
Timezone The global time zone shift from Greenwich Mean

Time (GMT); Western hemisphere time zones are denoted by negative
numbers Timezone HH

Grid Specifies the requested output sub

- grid’s lower left

(LL) and upper right (UR) corners; Grid corners can be specified by grid cell I, j coordinates (IJ), latitude and longitude (LL or LATLON) or MM5/WRF projected coordinate system (KM) GRID IJ iLL jLL iUR jUR
Or
GRID LL LatLL LonLL LatUR

LatRR
Or GRID KM xLL yLL xUR yUR
Point Outpu t point for AERMET, AERMOD, or

AERCOARE processing. The point can be specified by grid cell I, j coordinates (IJ), latitude and longitude (LL or LATLON) or MM5/WRF projected coordinate system (KM). An optional time zone
shift can also be listed 1 . The poi nt keyword can be repeated for each point to be outputted. Point IJ I J [Timezone]
Or POINT LL Lat Lon [Timezone]

Or POINT KM X Y [Timezone]

Layers Specify the output layer structure. Layers can be

aggregated (K), interpolated using layer tops (TOP),

or interpolated using mid layer (MID). Layers K Layer 1 Layer 2 ...Layer N Or Layers TOP Top 1 Top 2 ...Top N

Or Layers MID Mid 1 Mid 2 ...Mid N Origin Over

- ride the X,Y grid origin values found in the

MM5 or WRF output file. The user specifies a latitude (LAT) and longitude (LON). Origin LAT LON

PBL_recalc A value of FALSE (default value) causes MMIF to

pass through the PBL depth from the model with no changes. A value of TRUE causes MMIF to re

calculate PBL depths using a Bulk Richardson approach with 20 times the vertica l resolution of the
model data. PBL_recalc FALSE
Or PBL_recalc TRUE

AER_MIN_SPEED Specify the minimum wind speed in m/s (VALUE)

for AERMOD surface output file. AER_MIN_SPEED VALUE

FSL_INTERVAL Specify the number of hours (VALUE) to write for

each day to the upper air file for input into AERMET. The default value is 12 representing the 00Z and 12Z soundings. A value of 6 would write output for 00Z, 06Z, 12Z, and 18Z. A value of 1 would write output for each model hour. FSL_INTERVAL VALUE5

Table 1 . Conti nued

Keyword Description Syntax AER_LAYERS Specify the lowest and highest layer indices (two

integers) to write to the AERMET input site

- specific data and AERMOD profile file (PFL file). All layers
between the two indices will be written to the file. AER_LAYERS VALUE

OUTPUT Specifies the outputs from MMIF for AERMET,

AERCOARE, and AERMOD (MODEL keyword) and output files 2

. OUTPUT MODEL FORMAT
FILENAME

INPUT Input MM5 or WRF filename. This input is repeatable

for a MMIF run. INPUT FILENAME

METFORM Ke yword to tell MMIF which model MM5 or WRF is

being accessed. MMIF can auto

- detect the model type so in general this is not needed. METFORM MM5
Or
METFORM WRF
1. See Section 4.2 of the MMIF user’s guide regarding the global time zone shift and point specific time zone

shifts.

2. More information about the output options are discussed in Section 3.2 below.6

3.2 Recommended options for selected keywords

While most input options will be left to the discretion of the user, some recomme ndations on inputs are made in this guidance . One such option is the output option of MMIF, keyword OUTPUT. While MMIF can process data for input into AERMET, or AERMOD, the requirement for regulatory applications is to process the prognostic meteorological data for input

into AERMET as discussed in Sections 8.4.2(a) and 8.4.5.1(b) of the proposed Appendix W, as AERMET is the meteorological pre

- processor for AERMOD as discussed in those sections.

. The data is then processed in AERMET for input into AERMOD. Processing MMIF out put through AERMET also allows the user to take advantage of some of the options in AERMET, such as the u* adjustment option. See the AERMET user’s guide and addendum for details about options (U.S. EPA, 2004; U.S. EPA, 2015b). For non

- regulatory applica tions, the user may choose AERMET or AERMOD and should consult with and seek concurrence from collaborating agencies or parties involved in such modeling application s

.

3.2.1 Outputs

For any particular air quality model, the OUTPUT option is used to specify several files. While these are discussed in the MMIF user’s guide in detail, they are summarized below for AERMET

and subsequent input AERMOD and direct input into AERMOD as well ( non

- regulatory applications)

.

3.2.1.1 AERMET

For AERMET, the first set of files is specified using the USEFUL keyword. This keyword creates a DOS batch file or Linux shell script that is used to run all three stages of AERMET in

batch mode. It also crea tes the stage 1, stage 2, and stage 3 input files with the appropriate values set for the AERMET keywords such as LOCATION, XDATES, etc. Once the stage 1, 2, and 3 input files have been created, the user should check those files to ensure the correct GMT offset is used. For the upper air pathway of the stage 1 file, the LOCATION keyword should have a GMT offset corresponding to the station’s location. For example, if the processed grid

cell is in the Eastern timezone of the U.S. the GMT offset on the LOC ATION keyword should be 5. For the surface data, the offset should be zero as that has been formatted for local time.

The second file that is generated is specified using the keyword ONSITE. This creates a site

specific type meteorological file that is p rocessed via the ONSITE keyword in AERMET (U.S. EPA, 2014). This file contains 2

- meter and 10

- meter data and upper air data up to levels specified with the keywords MIN_LAYER, MAX_LAYER, or LAYERS to control the number of output layers.

The third keyword, FSL creates a file that mimics an upper air data file in the Forecast Systems Laboratory (FSL) format. The keyword UPPERAIR can also be used. See Section 2.2.1 of the MMIF user’s guide for more details.7

The final keyword is AERSFC, which generates an A ERSURFACE type output file with surface characteristics (albedo, Bowen ratio, and surface roughness). Note, that these are monthly surface characteristics for the period being processed. See Section 2.2.1 of the MMIF user’s guide for more details.

3.2.1 .2 AERMOD

Three files are generated for AERMOD. The USEFUL file is a file containing the ME pathway information of the AERMOD input file, i.e. ME STARTING, SURFFILE, PROFFILE, SURFDATA, UADATA, etc. information. The SFC keyword generates the AERMOD ready surface data file and the PFL keyword generates the profile data file for input into AERMOD.

3.2.2 Output layers and heights

An important keyword for output is the LAYERS keyword. As shown in Table 1, the user can specify different options for the output layers from MMIF. While the choice of layers is case specific and may be dependent on the prognostic model’s layer structure, a default use of MID (interpolation using layer mid

- point heights) and the specification of heights corresponding to the

AERMO D vertical grid heights should be adequate in most cases. These heights are: 25, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500 , 4000, 4500, and 5000. These values have been used in p ast MMIF evaluations (U.S. EPA, 2015c).

3.2. 3 Grid cells to process

An AERMOD run uses surface meteorological data from one point and upper air data from one point. While MMIF can process multiple points, i.e. grid cells, the grid cell used in the

AERMOD simulation should be representative of the modeling domain, following the recommendations of Section 8.4.5(b) of Appendix W. Depending on the size of the modeling domain and the grid resolution of the prognostic meteorological data, most often the

repres entative grid cell will be the grid cell containing the facility of interest. This will often be the case for NSR/PSD types of applications. When the AERMOD modeling domain overlaps several grid cells of the prognostic meteorological data , such as for SI P demonstrations , the grid cell that is most representative of the domain should be selected following guidance on representativeness in Sections 8.4.1.b and 8.4.2.b of the proposed Appendix W.

3.3 Surface characteristics

MMIF will output surface characte ristics, albedo, Bowen ratio, and surface roughness for input into AERMET and also in the AERMOD ready surface meteorological file. When outputting data for AERMET, MMIF outputs surface characteristics for one 360o sector at monthly8

resolution. The surfa ce characteristics are based on the landuse data used by the prognostic meteorological model. These surface characteristics should be used as they are representative of the processed grid cell as discussed in Section 8.4.2(b) of the proposed Appendix W.

3.4 Treatment of low winds

When processing MMIF for input into AERMET, MMIF will generate the onsite wind speed threshold option (THRESHOLD keyword) with a value of 0.5 m/s for the stage 1 AERMET input file. The model user has the option to include this option when running AERMET. See the AERMET user’s guide and addendum (U.S. EPA, 2004; U.S. EPA, 2015b) for details about AERMET this option. When generating MMIF output for direct AERMOD input, winds below

0.5 m/s are treated as calms in the AERMOD surfac e file.

3. 5 Post

- processing of outputs

When processing MMIF for AERMET files, a single MMIF run will produce an upper air file in the FSL format, a surface data file that will be read into AERMET as site

- specific data, and surface characteristics (albedo, Bowen ratio, and surface roughness) at monthly resolution for twelve sectors. These output files will cover the period processed in MMIF. In most situations, a single MMIF run will not cover an entire three period or even a one year period. If that is the case, the ONSITE files generated by the MMIF can be simply concatenated into a single file for the three year period or individual yearly files before input into AERMET. The files must be concatenated in temporal order. The same can be done for the F SL files. If using the MMIF surface characteristics files, the AERSFC files cannot be simply concatenated. For a single MMIF run, the surface characteristics are output for all twelve months and sectors. The months outside of the data processing window set by START and STOP will have missing values, while

the months inside the window will have non

- missing values. To create a valid AERSFC file covering the entire three year period or desired period, an AERSURFACE file must be created

with non

- missing val ues for all months and sectors. This can be created by simply cutting and pasting the non

- missing values for each month/sector combination into a single file. When creating this file, the user should make sure to incorporate the header line from one of t he files into the concatenated file. This line is “** Generated by MMIF...” This line indicates to AERMET that the meteorological data comes from MMIF and not an observed site

- specific dataset. This information is then passed to AERMOD via the surface mete orological file created by AERMET. While this does not affect the data calculations in AERMET and AERMOD, including the line ensures transparency when data files are reviewed.

An alternative approach to the file concatenation steps described above, is to r un AERMET for each period processed and concatenate AERMOD ready surface and profile files from the multiple AERMET runs. For the profile files, the files can be simply concatenated together, preserving the temporal order of the data (e.g., January 1, hou r 1 of the first processed year is the first line and December 31, hour 24 of the last processed year is the last record of the9

concatenated file). For the surface files, AERMET generates a header record for each file (the record that lists the location, s tation identifiers, and AERMET version). When concatenating the surface files, the header record for the first concatenated file should be retained. Only the data records from the remaining surface files are needed. If the header records are retained fo r all files, AERMOD will not run correctly. Again, the files should be concatenated in temporal order. These steps also apply for processing AERMOD ready files when post

- processing MMIF output for AERMOD.10

4. References

Appel, K.W., Gilliam, R.C., Davis, N., Zubrow, A., and Howard, S.C.: Overview of the Atmospheric Model Evaluation Tool (AMET) v1.1 for evaluating meteorological and air quality models, Environ. Modell. Softw ., 26, 4, 434

- 443, 2011.

Environ, 2014: The Meso s cale Model Interface Program (MMIF) Version 3.1 User’s Manual.

Grell, G., J. Dudhia, and D.R. Stauffer: A description of the fifth

- generation Penn State/NCAR

M esoscale M odel (MM5), NCAR Tech. Note NCAR/TN

- 398+STR, 122 pp.

Skamarock, W. C., Klemp, J. B., D udhia J., Gill, D. O., Barker, D. M., Duda, M. G., Huang, X.

- Y., Wang, W., and Powers, J. G.: A Description of the Advanced Research WRF Version 3, National Centre of Atmospheric Research, Boulder, Colorado, 2008.

U.S. EPA, 2004: User’s Guide for the AERM OD Meteorological Preprocessor (AERMET).
EPA

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NC 27711.

U.S. EPA, 2015a. Guideline on Air Quality Models . 40 CFR Part 51 Appendix W.

U.S. EPA, 2015b: Addendum

- User’s Guide for the AERMOD Meteorological Preprocessor (AERMET). EPA

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- 002. U.S. Environmental Protection Agency, Research Triangle Park, NC 27711.

U.S. EPA, 2015c: Evaluation of Prognostic Meteorological Data in AERMOD Applications.

EPA

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27711.United States
Environmental Protection Agency Office of Air Quality Planning and Standards Air Quality Assessment Division Research Triangle Park, NC Publication No. EPA

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