SMEPA – R D 

1-HOUR SO2 NAAQS DESIGNATION 

MODELING REPORT

South Mississippi Electric Power Association>

R D Morrow, Sr. Generating Plant, Lamar County, MS

Prepared By:

TRINITY CONSULTANTS

One Galleria Blvd., Suite 1830

Metairie, Louisiana - 70001

(504) 828-5845

August 2015

151902.0007

Environmental solutions delivered uncommonly well
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TABLE OF CONTENTS

1. EXECUTIVE SUMMARY 1-1

2. INTRODUCTION 2-1

3. 1-HOUR SO2 DESINGATION MODELING PROCEDURES 3-1

3.1. Model Selection .........................................................................................................................................................3-1

3.2. Meteorological Site Selection and Representativeness..............................................................................3-1

3.3. AERMET preprocessing ..........................................................................................................................................3-7

3.3.1. Surface Data...........................................................................................................................................................................3-7

3.3.2. Upper Air Data.......................................................................................................................................................................3-7

3.3.3. Land Use Data........................................................................................................................................................................3-7

3.3.4. AERMET Processing Options............................................................................................................................................3-8

3.4. Coordinate System ...................................................................................................................................................3-8

3.5. Receptor Locations...................................................................................................................................................3-9

3.6. Terrain Elevations....................................................................................................................................................3-9

3.7. Building Influences ..................................................................................................................................................3-9

3.8. Urban/Rural Determination...............................................................................................................................3-10

3.9. SMEPA Source Identification and Characterization...................................................................................3-10

3.10. Emissions Inventories for Nearby Sources.................................................................................................3-10

3.11. Model Input – Source Parameters..................................................................................................................3-11

3.12. Background Concentration ..............................................................................................................................3-12

3.12.1. Comparison of Near-by Emissions Sources........................................................................................................... 3-12

3.12.2. Comparison of Surface Characteristics and Land Use Types.......................................................................... 3-12

4. 1-HOUR SO2 DESIGNATION MODELING RESULTS 4-1

4.1. Modeling Results.......................................................................................................................................................4-1

5. ELECTRONIC FILES 5-1

APPENDIX A: MODELING PROTOCOL A

APPENDIX B: MS AERMOD READY MET FILES - SUPPORTING DOCUMENTATION B

APPENDIX C: RAIN CII CARBON HOURLY EMISSIONS CALCULATIONS C

APPENDIX D: AERSURFACE OUTPUT D

APPENDIX E: SO2 MONITOR VALUES REPORT E
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LIST OF FIGURES

Figure 3-1. Terrain Map around the Bobby L Chain Municipal Airport Station within Approximately 3 Km 

Radius 3-3

Figure 3-2. Terrain Features around the Morrow Plant within Approximately 3 Km Radius 3-4

Figure 3-3. Land Use within 1 Km and 3 Km Radius around the Meteorological Station 3-5

Figure 3-4. Land Use within 1 Km and 3 Km Radius around the Morrow Plant 3-6

Figure 3-5. Land Use within 1 Km and 3 Km Radius around the Jackson Monitoring Station (Site ID: 

280490020) 3-14

Figure 4-1. Contour Plot Showing the Concentration Gradient 4-1
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LIST OF TABLES

Table 1-1. SO2 Designation Modeling Results 1-1

Table 3-1. Comparison of Surface Characteristics Values between Meteorological Station and Morrow Plant 3-2

Table 3-2. AERSURFACE Input Parameters 3-8

Table 3-3. GEP Stack Height Analysis 3-9

Table 3-4. SMEPA Source Identification and Location 3-10

Table 3-5. Nearby SO2 Source Analysis 3-11

Table 3-6. Source Parameters for SO2 Designation Modeling 3-11

Table 3-7. Surface Characteristics Analysis of Jackson Monitoring Station and the Morrow Plant 3-13

Table 4-1. 4th - Highest Averaged Modeled Concentration based on Actual Emission Rates (2012-2014) 4-2

Table 5-1. AERMOD Input and Output File Descriptions for the Air Quality Dispersion Modeling Analysis 5-2

Table 5-2. Meteorological Files Used for the Air Quality Dispersion Modeling Analysis 5-2

Table 5-3. Other Associated Files 5-2
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1. EXECUTIVE SUMMARY

The South Mississippi Electric Power Association (SMEPA) owns and operates the R D Morrow, Sr. Generating 

Plant (Morrow Plant). SMEPA conducted sulfur dioxide (SO2) designation modeling to determine whether the 

area around the Morrow Plant should be designated as attainment or non-attainment. SMEPA has submitted a 

SO2 designation modeling protocol (See Appendix A) to the Mississippi Department of Environmental Quality 

(MDEQ) in June 2015 and was also approved by the U. S. Environmental Protection Agency (U. S. EPA) via 

conference call on July 09, 2015. SMEPA conducted the SO2 designation modeling using the U.S. EPA’s preferred 

air dispersion model for near-field regulatory applications, the American Meteorological Society/Environmental 

Protection Agency Regulatory Model (AERMOD). SMEPA used the following dispersion modeling methodology

to determine the designation status of the area around the Morrow Plant:

Used the most recent three (3) years of actual emissions (2012, 2013, and 2014);

Used three (3) years of meteorological data (2012, 2013, and 2014);

Used actual stack heights rather than limiting model stack heights to GEP height; and

Included near-by sources from the regional inventories provided by the MDEQ.

SMEPA conducted the dispersion modeling in accordance with the modeling protocol approved by the U.S. EPA. 

Table 1-1 shows the dispersion modeling results and indicates the area around the Morrow Plant should be 

classified as “attainment” and SMEPA is not causing or contributing to any violations of the 1-hour SO2

National Ambient Air Quality Standards (NAAQS). Detailed modeling procedure and analysis are discussed in the 

following sections.

Table 1-1. SO2 Designation Modeling Results

Years 2012 2013 2014

4th Maximum Modeled Concentration a, g/m3 125.11 123.02 131.42

Design Value Concentration b, g/m3 115.17 123.02 95.89

4th Highest Averaged Concentration (2012-2014) c, g/m3 (ppb) 111.36 (42.50)

Background Concentration1, g/m3 (ppb) 36.65 (13.99)

NAAQS + Background, g/m3 (ppb) 148.01 (56.49)

NAAQS2, g/m3 (ppb) 196.34 (75.00)

NAAQS Exceedance (Yes/No) No

a The maximum modeled concentration represents the 4th highest maximum concentration predicted for 2012, 2013, and 2014.

b Design value concentration is the modeled concentration in a receptor that yielded the design value of the NAAQS (average of 

4th highest concentration for three years)

c

 4th highest averaged concentration is the design value of the NAAQS (average of design value concentrations of three years)

 

1 The background concentration was provided by the MDEQ obtained from the air monitoring station (Site ID: 280490020) at 

Jackson, MS

2 SO2 NAAQS of 75 ppb or 0.075 ppm was obtained from http://www.epa.gov/air/criteria.html. In accordance with the Primary 

National Ambient Air Quality Standard for Sulfur Dioxide (http://www.gpo.gov/fdsys/pkg/FR-2010-06-22/html/2010-13947.htm) 

final rule, Table B-1 footnote, ppm was converted to g/m3 by multiplying by M/0.02447, where M is the molecular weight (64.06 

lb/lbmol).
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2. INTRODUCTION

The Morrow Plant is located in Lamar County, Mississippi, which is currently classified as attainment for all 

criteria pollutants3. The Plant is currently operating under the Title V Permit No. 1440-00021, issued by the

MDEQ.

On June 2, 2010, the U.S. EPA revised the primary NAAQS for SO2 by establishing a 1-hour standard at a level of 

75 parts per billion (ppb)4, which is equivalent to 196.34 g/m3. The form of the 1-hour SO2 NAAQS standard is 

a 3- year average of the 99th percentile of the annual distribution of daily maximum 1-hour average 

concentrations. 

Following the U.S. EPA’s May 2014 publication of the proposed Data Requirements Rule, the U.S. EPA was sued 

for “failing to undertake a certain nondiscretionary duty under the Clean Air Act (“CAA”), 42 U.S.C. §§ 7401-7671q, 

and that such alleged failure is actionable under section 304(a)(2) of the CAA, 42 U.S.C. § 7604(a)(2)”. The lawsuit 

resulted in a Consent Decree that was entered on March 2, 2015 in the U.S. District Court for the Northern 

District of California5. As a result of the Consent Decree, an additional designation phase was added to the two 

designation phases that were already included in the U.S. EPA’s May 2014 proposed Data Requirements Rule. 

The additional phase affects areas with stationary sources that meet specific emission criteria laid out in the 

Consent Decree. The U.S. EPA released a memorandum on March 20, 2015 (referred to herein as the 2015 SO2

Area Designation Guidance) to the Regional Directors clarifying the path forward for states with sources affected 

by the decree.

6

The Consent Decree requires the U.S. EPA to complete a round of SO2 designations for the areas affected by the 

Consent Decree by July 2, 2016. The U.S. EPA is expected to release a final version of the Data Requirements 

Rule around September 2015. It is expected that the Data Requirements Rule will address all three remaining 

phases of the designation process.

The Morrow Plant meets the emission criteria laid out in the consent decree. The U.S. EPA has listed the Morrow 

Plant as a source exceeding the established threshold with actual annual emissions of 3,948 TPY and emission 

rate of 0.63 lbs/MMBTU based on 2012 emissions data.

7 Thus, the U.S. EPA is required to designate the area 

surrounding the Morrow Plant by July 2, 2016. Because the Consent Decree does not provide sufficient time to 

commission representative ambient air monitors, SMEPA has decided to utilize an air dispersion modeling

analysis to determine attainment status. Therefore, in accordance with the EPA’s May 2014 proposed Data 

Requirements Rule8, an SO2 designation for the area surrounding the Morrow Plant will be based on the 

predictions of the air dispersion modeling analysis presented in this modeling report. The U.S. EPA published a 

draft Technical Assistance Document (TAD) in December 2013 describing the approach that should be 

considered when conducting dispersion modeling in support of a 1-hour SO2 NAAQS designation9 (referred to 

herein as the 2013 SO2 NAAQS Modeling TAD). To determine the attainment status, Trinity Consultants 

 

3 http://www.epa.gov/oaqps001/greenbk/ancl.html

4 http://www.epa.gov/air/criteria.html. Final rule signed June 2, 2010

5 http://www.epa.gov/so2designations/pdfs/201503FinalCourtOrder.pdf

6 http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/20150320SO2designations.pdf

7 http://www.epa.gov/airquality/sulfurdioxide/designations/pdfs/sourceareas.pdf

8 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OAR-2013-0711-0001

9 http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/SO2ModelingTAD.pdf
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(Trinity) conducted the dispersion modeling on behalf of SMEPA to predict the SO2 concentrations in the area 

surrounding the Morrow Plant and the results are attached to this report. This modeling report includes the 

following:

1-Hour SO2 Designation Modeling Procedure

1-Hour SO2 Designation Modeling Results

Electronic Files

Appendix A – Modeling Protocol

Appendix B – MDEQ Met Data Guidance

Appendix C – Rain CII Carbon Hourly Emissions Calculations

Appendix D – AERSURFACE Output

Appendix E – SO2 Monitor Values Report
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3. 1-HOUR SO2 DESINGATION MODELING PROCEDURES

3.1. MODEL SELECTION

Trinity performed 1-hour SO2 modeling using EPA’s preferred AERMOD Version 14134 using input files 

developed using Trinity’s BREEZE Software. AERMOD is a steady-state Gaussian dispersion model based on 

planetary boundary layer turbulence structure and scaling concepts, including treatment of both surface and 

elevated sources, and both simple and complex terrain10.

3.2. METEOROLOGICAL SITE SELECTION AND REPRESENTATIVENESS

SMEPA used the meteorological data collected at the Bobby L Chain Municipal Airport Station (WBAN: 13833). 

SMEPA believes that the meteorological data collected at this site is representative for the Morrow Plant based 

on the proximity, surface characteristics, and land use types. The Bobby L Chain Municipal Airport Station is 

approximately 9 miles from the center of the Morrow Plant. Terrain between the project site and the 

meteorological station is generally flat and there are no complex or elevated terrain features. A visual inspection

of the terrain map indicated that the terrain features are similar for the meteorological station and the Morrow 

Plant. The terrain maps are shown in Figure 3-1 and Figure 3-2. Also, the surface characteristic comparison was 

conducted between the meteorological station and the Morrow Plant. Table 3-1 shows the surface 

characteristics (i.e., albedo, Bowen-ratio, and surface roughness) values of the meteorological station and the 

Morrow Plant. In accordance with U.S. EPA guidance, these values were determined using the latest version of 

the U.S. EPA AERSURFACE tool (version 13016) with a 1 km radius used to define surface roughness.

11

 Please 

refer Appendix D for AERSURFACE output. The albedo and Bowen-ratio values were similar for both the 

meteorological station and the Morrow Plant. As a typical case, the difference in the surface roughness values 

between the meteorological station and the Morrow Plant is due the difference in the land use types. The 

meteorological station has varying land use types for each sector whereas the Morrow Plant has same land use 

type for each sector, mostly of mixed forest. The land use types around the meteorological station and the 

Morrow Plant within a 3-Km radius shown in Figure 3-3 and Figure 3-4. The surface characteristics used to 

process the meteorological data may result in a more conservative concentrations as a result of the smaller 

roughness lengths. The smaller roughness length in the pre-processed data would result in less turbulent 

conditions. The less turbulent condition would not facilitate good dispersion, thus resulting in higher impacts. 

Based on the proximity, topography, and surface characteristics analysis, SMEPA concludes that meteorological 

data collected at this meteorological station (KHBG) would be representative of the meteorological conditions at 

the Morrow Plant.

 

10 http://www.epa.gov/ttn/scram/dispersion_prefrec.htm#aermod

11 U.S. Environmental Protection Agency. 2013. “AERSURFACE User’s Guide.” EPA-454/B-08-001, Revised 01/16/2013. Available 

Online: http://www.epa.gov/scram001/7thconf/aermod/aersurface_userguide.pdf
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Table 3-1. Comparison of Surface Characteristics Values between Meteorological Station and Morrow 

Plant

Month Sector

Surface Characteristics Analysis

Albedo Bowen-Ratio Surface Roughness

Met 

Station

Morrow 

Plant

Met 

Station

Morrow 

Plant

Met 

Station

Morrow 

Plant

1 1 0.15 0.14 0.63 0.79 0.037 0.309

2 1 0.15 0.14 0.63 0.79 0.037 0.309

3 1 0.14 0.14 0.48 0.60 0.051 0.370

4 1 0.14 0.14 0.48 0.60 0.051 0.370

5 1 0.15 0.15 0.34 0.34 0.068 0.460

6 1 0.15 0.15 0.34 0.34 0.068 0.460

7 1 0.15 0.15 0.34 0.34 0.068 0.460

8 1 0.15 0.15 0.34 0.34 0.068 0.460

9 1 0.15 0.15 0.34 0.34 0.068 0.460

10 1 0.15 0.15 0.63 0.79 0.058 0.455

11 1 0.15 0.15 0.63 0.79 0.058 0.455

12 1 0.15 0.14 0.63 0.79 0.037 0.309
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Figure 3-1. Terrain Map around the Bobby L Chain Municipal Airport Station within Approximately 3 Km 

Radius
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Figure 3-2. Terrain Features around the Morrow Plant within Approximately 3 Km Radius
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Figure 3-3. Land Use within 1 Km and 3 Km Radius around the Meteorological Station
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Figure 3-4. Land Use within 1 Km and 3 Km Radius around the Morrow Plant
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3.3. AERMET PREPROCESSING

AERMOD-ready meteorological data was prepared using Version No. 14134 of the U.S. EPA’s AERMET 

meteorological processing utility. The met data was generated in accordance with the MS AERMOD Ready Met 

Files – Supporting Documentation, July 01, 2014 as attached in Appendix B.

3.3.1. Surface Data

Raw hourly surface meteorological data were obtained from the U.S. National Climactic Data Center (NCDC) for 

Bobby L Chain Municipal Airport Station (KHBG, WMO ID: 724560) in the standard ISHD format. This data was 

supplemented with TD-6405 (so-called “1-minute”) wind data from KHBG. The 1-minute wind data was 

processed using the latest version of the U.S. EPA AERMINUTE pre-processing tool (version 14337). The quality 

of the 1-minute data was verified by comparison to the hourly ISHD data from KHBG. 

3.3.2. Upper Air Data

In addition to surface meteorological data, AERMET requires the use of data from a sunrise-time upper air 

sounding to estimate daytime mixing heights. Upper air data from the nearest U.S. National Weather Service 

(NWS) upper-air balloon station, located in Jackson, Mississippi (WBAN: 03940), was obtained from the National 

Oceanic and Atmospheric Administration (NOAA) in FSL format. AERMOD-ready meteorological data was 

prepared using Version No. 14134 of the U.S. EPA’s AERMET meteorological processing utility. The met data 

was generated in accordance with the MS AERMOD Ready Met Files – Supporting Documentation as attached in 

Appendix B.

3.3.3. Land Use Data

Parameters derived from the analysis of land-use data (surface roughness, Bowen ratio, and albedo) are also 

required by AERMET. In accordance with U.S. EPA guidance, these values will be determined using the latest 

version of the U.S. EPA AERSURFACE tool (version 13016).12 The AERSUFACE settings that were used for 

processing are summarized in Table 3-2 below. The met station coordinates were determined by visually 

identifying the met station using Google Earth. NLCD 1992 (CONUS) Land Cover data used in AERSURFACE 

processing was obtained from the Multi-Resolution Land Use Consortium (MRLC). 

U.S. EPA guidance dictates that on at least an annual basis, precipitation at a surface site should be classified as 

wet, dry, or average in comparison to the 30-year climatological record at the site. This determination is used to 

adjust the Bowen ratio estimated by AERSURFACE. To make the determination, annual precipitation in each 

modeled year (2012 to 2014) was compared to the 1981 to 2010 climatological record for KHBG.

13 The 30th and 

70th percentile values of the annual precipitation distribution from 1981 to 2010 were calculated. Per U.S. EPA 

guidance, each modeled year was classified for AERSUFACE processing as “wet” if its annual precipitation was 

higher than the 70th percentile value, “dry” if its annual precipitation was lower than the 30th percentile value, 

and “average” if it was between the 30th and 70th percentile values. The values that were used in this case are 

summarized in Table 3-1. The values are based on the MS AERMOD Ready Met Files – Supporting 

Documentation attached as Appendix B.

 

12 U.S. Environmental Protection Agency. 2013. “AERSURFACE User’s Guide.” EPA-454/B-08-001, Revised 01/16/2013. Available 

Online: http://www.epa.gov/scram001/7thconf/aermod/aersurface_userguide.pdf

13 National Climactic Data Center. 2010 Local Climatological Data (LCD).
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Table 3-2. AERSURFACE Input Parameters

AERSURFACE Parameter Value

Met Station Latitude 31.269483

Met Station Longitude -89.256108

Datum NAD 1983

Radius for surface roughness (km) 1.0

Vary by Sector? Yes

Number of Sectors 12

Temporal Resolution Monthly

Continuous Winter Snow Cover? No

Station Located at Airport? Yes

Arid Region? No

Surface Moisture Classification Average

3.3.4. AERMET Processing Options

Standard AERMET processing options were used.

14,15 The options elected included:

MODIFY keyword for upper air data

THRESH_1MIN 0.5 keyword to provide a lower bound of 0.5 m/s for 1-minute wind data

AUDIT keywords to provide additional QA/QC and diagnostic information

ASOS1MIN keyword to incorporate 1-minute wind data

NWS_HGT WIND 10 keyword to designate the anemometer height as 10 meters

METHOD WIND_DIR RANDOM keyword to correct for any wind direction rounding in the raw ISHD data

METHOD REFLEVEL SUBNWS keyword to allow use of airport surface station data

Default substitution options for cloud cover and temperature data was not overridden

Default ASOS_ADJ option for correction of truncated wind speeds was not overridden

ADJ_U* beta option was not used

3.4. COORDINATE SYSTEM

In all modeling input and output files, the locations of emission sources, structures, and receptors were

represented in Zone 16 of the Universal Transverse Mercator (UTM) coordinate system using datum World 

Geodetic System (WGS) 1984, which is comparable to the North American Datum 1983 (NAD83). The Morrow 

Plant is approximately centered at UTM, Zone 16, coordinates 272,009 meters East and 3,456,266 meters north. 

The base elevation of the facility is approximately 79 meters above mean sea level.

 

14

 Fox, Tyler, U.S. Environmental Protection Agency. 2013. “Use of ASOS Meteorological Data in AERMOD Dispersion 

Modeling.” Available Online: http://www.epa.gov/ttn/scram/guidance/clarification/20130308_Met_Data_Clarification.pdf

15 U.S. Environmental Protection Agency. 2014. “User’s Guide for the AERMOD Meteorological Preprocessor (AERMET)”. 

EPA-454/B-03-002, November 2004).
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3.5. RECEPTOR LOCATIONS

The dispersion modeling used a combination of a Cartesian grid system centered on the Morrow Plant and 

discrete receptor points along the facility’s fence line. Receptors were placed at 25-meter intervals along the 

fence line, 100-meter intervals out to a distance of 2.5 kilometers (km) and at 500-meter intervals out to 10 km.

3.6. TERRAIN ELEVATIONS

The terrain elevation for each receptor, building, and emission source was determined using USGS 1/3-arcsecond National Elevation Data (NED). The NED, obtained from the USGS, has terrain elevations at 10-meter 

intervals. Using the AERMOD terrain processor, AERMAP (version 11103), the terrain height for each receptor, 

building, and emission source included in the model was determined by assigning the interpolated height from 

the digital terrain elevations surrounding each source.

In addition, AERMAP was used to compute the hill height scales for each receptor. AERMAP searches all NED 

points for the terrain height and location that has the greatest influence on each receptor to determine the hill 

height scale for that receptor. AERMOD then uses the hill height scale in order to select the correct critical 

dividing streamline and concentration algorithm for each receptor.

3.7. BUILDING INFLUENCES

The U.S. EPA’s Building Profile Input Program (BPIP) with Plume Rise Model Enhancements (PRIME) (Version 

04274), was used to account for Morrow Plant building downwash influences in the model. The purpose of a 

building downwash analysis is to determine if the plume discharged from a stack will become caught in the 

turbulent wake of a building (or other structure), resulting in downwash of the plume. The downwash of the 

plume can result in elevated ground‐level concentrations of SO2. SMEPA did not include any buildings from 

nearby sources in the model. For both the scenarios, actual height was lower than the GEP stack height. Table 

3-3 shows the GEP Stack height analysis for both modeling scenarios. The actual stack heights modeled are less 

than the GEP Stack height, which satisfies the GEP requirement of 40 CFR Part 51 Appendix W.

Table 3-3. GEP Stack Height Analysis

Stack Name Actual Stack 

Height, m

GEP Stack 

Height, m16

Complies GEP 

Requirements

Unit 1 – AA-001 123.50 144.17 Yes

Unit 2 – AA-002 123.50 144.51 Yes

RainCII 34.75 65 Yes

 

16 GEP Stack height was calculated using Equation 1 from Technical Support Document for Determination of Good 

Engineering Practice Stack Height, pg. 2
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3.8. URBAN/RURAL DETERMINATION

SMEPA used the Auer Method to determine the urban or rural classification. Accordingly, the following 

procedure was used by SMEPA to determine the classification:

The land use types within a 3 Km radius from the center of the Morrow Plant were analyzed;

In accordance with Appendix W Guideline on Air Quality Models, if the land use types I1, I2, C1, R2, and 

R3 account for 50 percent or more of the total area analyzed, urban dispersion coefficients should be 

used.

Based on the visual inspection of the land use types shown in Figure 3-4, approximately 65% of the area 

represents mixed forest (Deciduous and Evergreen) and approximately 20% of the area represents 

Pasture/Hay. Hence, SMEPA used the default “rural” AERMOD options for this modeling.

3.9. SMEPA SOURCE IDENTIFICATION AND CHARACTERIZATION

There are two boilers at the Morrow Plant were analyzed in this dispersion modeling. The stacks for the boilers 

were modeled as point sources. Table 3-4 below summarizes the stack parameters used for the dispersion 

modeling. Trinity used the hourly data collected by the Continuous Emission Monitoring System (CEMS) for 

2012, 2013, and 2014. The CEMS data was provided by SMEPA. AERMOD has several options for emissions to 

temporally vary within a model simulation. CEMS data were incorporated in the dispersion modeling using the 

hourly varying emissions options (AERMOD keyword: HOUREMIS) to represent the variability in emissions 

accurately. In addition, SMEPA incorporated varying hourly temperature and air flow rate data corresponding to 

the hourly emissions data. For any missing hourly emission data, the maximum of the previous hourly emission 

data and the next hourly emission data was used to be conservative. If more than one hourly data were missing, 

the maximum daily hourly data of that particular data was used. Please see attached modeling CD for the Hourly 

Emission Rates File and supporting CEMS data.

Please note that although there are additional sources of SO2 emissions (all Compression Ignition Emergency 

Engines) in operation at the Morrow Plant, the 2013 SO2 NAAQS Modeling TAD, Section 5.4, states that sources 

such as emergency engines/fire water pumps do not need to be modeled because they are intermittent, are not 

in continuous operation, and would have negligible contribution to the annual distribution of the daily 

maximum 1-hour SO2 concentration. SMEPA believes that emissions from the emergency equipment fit these 

criteria; therefore, they have not been included in this analysis.

Table 3-4. SMEPA Source Identification and Location

Emission 

Point

UTM East

(m)*

UTM North

(m)*

Stack 

Height 

(ft.)

Stack 

Diameter 

(ft.)

Exit 

Velocity 

(ft./s)

Exit 

Temperature 

(F)

Emission 

Rate 

(lb/hr)

AA-001 271955.1 3456195 405.2 16.7 CEMS CEMS CEMS

AA-002 271962.1 3456195 405.2 16.7 CEMS CEMS CEMS

*UTM Zone 16, NAD 83

3.10. EMISSIONS INVENTORIES FOR NEARBY SOURCES

Other sources of SO2 emissions in the area surrounding the Morrow Plant were included in the model. SMEPA 

requested the emissions inventory from the MDEQ. Based on the emissions inventory data provided by the 
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MDEQ, SMEPA performed the analysis seen in Table 3-5 and described below to determine which nearby 

sources to include. In accordance with the modeling protocol, SMEPA has excluded all the near-by SO2 sources 

with emissions less than 10 tpy.

Table 3-5. Nearby SO2 Source Analysis

Source

Distance 

from 

SMEPA

(km)

Plant-Wide Actual SO2

Emissions, tpy

Selected for SO2

Designation 

Modeling? 

(Yes/No)

Reason

2012 2013 2014

Rain CII Carbon, 

LLC 3.85 717.22 718.3 498.63 Yes N/A

Leaf River 

Cellulose, LLC 33.42 62.65 65.38 Not Available No

Emissions are small 

relative to distance 

from SMEPA

SMEPA did not include the SO2 emissions from the Leaf River Cellulose, LLC facility based on the relative 

emission rate for the facility compared with the distance from the Morrow Plant. For the worst-case emissions 

year, the ratio is 1.95 (65.38 TPY/33.42 km), which indicates that the source is relatively small and distant from 

the Morrow Plant and can be represented through use of a background concentration rather than explicitly 

modeled. SMEPA included SO2 emissions from the Rain CII Carbon, LLC facility due to its close proximity to 

SMEPA in conjunction with their annual SO2 emissions. 

3.11. MODEL INPUT – SOURCE PARAMETERS

Table 3-6 shows the emission sources included in this SO2 designation modeling. For this modeling, SMEPA 

included the following sources:

Unit 1 – No. 1 Coal/Fuel Oil Fired Boiler;

Unit 2 – No. 2 Coal/Fuel Oil Fired Boiler; and

RainCII – Rain CII Carbon Facility (Source parameters are provided by the MDEQ)

Table 3-6. Source Parameters for SO2 Designation Modeling

Emission

Point

UTM East

(m)*

UTM North

(m)*

Stack 

Height (ft.)

Stack 

Diameter 

(ft.)

Exit 

Velocity 

(ft./s)

Exit 

Temperature 

(F)

Emission 

Rate 

(lb/hr)

AA-001 271955.1 3456195 405.2 16.7 CEMS CEMS CEMS

AA-002 271962.1 3456195 405.2 16.7 CEMS CEMS CEMS

RainCII 272373.5 3452147 114 8.60 16.9 405 See 

Appendix C

*UTM Zone 16, NAD 83
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3.12. BACKGROUND CONCENTRATION

SMEPA opted to choose a “regional monitor” for the purpose of defining a background concentration since there 

are no SO2 monitoring stations located at the Morrow Plant. Based on MDEQ’s recommendation, SMEPA selects 

the Jackson Monitoring Station (Hinds County) to obtain the background SO2 concentration. In addition, SMEPA 

performed a qualitative analysis to compare the Jackson Monitor site with the Morrow Plant site based on nearby emission sources, surface characteristics, and land use types. Based on the comparison, SMEPA believes that 

the Jackson Monitoring Station (Site ID: 280490020) is representative of the Morrow Plant.

3.12.1. Comparison of Near-by Emissions Sources

The only facility with significant SO2 emissions in the vicinity (i.e., within 50 Km) of the Jackson Monitoring 

Station is the Thomasville Gas Plant with 4,506 tpy in 2014 and the next largest would be Nucor Steel with 11 

tpy in 2014.17 This represents a similar or possibly conservative distribution of sources impacting the monitor 

to those in the vicinity of the Morrow Plant but not explicitly modeled. The only facility with significant SO2

emissions (i.e., greater than 10 tpy) within 50 Km of the Morrow Plant site, but not explicitly modeled is the Leaf 

River Cellulose facility with 48.55 tpy for 2014. Therefore, the use of the Jackson Monitor to represent SO2

concentrations from sources in the vicinity of the Morrow Plant, but not explicitly modeled in this analysis 

should be conservative.

3.12.2. Comparison of Surface Characteristics and Land Use Types

SMEPA evaluated the surface characteristics values (i.e., albedo, Bowen-ratio and surface roughness) of the 

Morrow Plant and the Jackson Monitoring Station. Based on the AERSURFACE analysis, the surface 

characteristics values were similar for the Jackson Monitoring Station and the Morrow Plant. Table 3-7 shows 

the comparison of surface characteristics values of Jackson monitoring station and the Morrow Plant. Please see 

Appendix C for AERSURFACE output. 

Figure 3-5 shows the land use types around the Jackson Monitoring Station. Unlike the area around the Morrow 

Plant, the area around the Jackson Monitoring station is mostly of low density residential, high density 

residential, and Commercial/Industrial/Transportation classification. Hence, area around the Jackson 

monitoring station can be considered as “urban”. The monitoring station would be expected to be impacted by 

larger sources of SO2 emissions, either nearby or more distant as discussed in Section 3.12.1, and by smaller, 

more local sources. SMEPA believes the SO2 background concentration obtained from the Jackson Monitoring 

Station would be conservative since the Morrow Plant is located in “rural” setting with less more local sources 

expected to be impacting the SMEPA Plant area as this area is more rural than the monitoring station. 

Based on the analysis of the near-by emission sources, surface characteristics values, and land use types, SMEPA 

concluded to use the background concentration obtained from the Jackson Monitoring Station consistent with 

the recommendation of MDEQ.

 

17 2014 SO2 emissions were provided by MDEQ via e-mail dated July 10, 2015.
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Table 3-7. Surface Characteristics Analysis of Jackson Monitoring Station and the Morrow Plant

Month Sector

Surface Characteristics Analysis

Albedo Bowen-Ratio Surface Roughness

Monitoring 

Station

Morrow 

Plant

Monitoring 

Station

Morrow 

Plant

Monitoring 

Station

Morrow 

Plant

1 1 0.17 0.14 0.81 0.79 0.337 0.309

2 1 0.17 0.14 0.81 0.79 0.337 0.309

3 1 0.16 0.14 0.65 0.60 0.386 0.370

4 1 0.16 0.14 0.65 0.60 0.386 0.370

5 1 0.16 0.15 0.63 0.34 0.405 0.460

6 1 0.16 0.15 0.63 0.34 0.405 0.460

7 1 0.16 0.15 0.63 0.34 0.405 0.460

8 1 0.16 0.15 0.63 0.34 0.405 0.460

9 1 0.16 0.15 0.63 0.34 0.405 0.460

10 1 0.16 0.15 0.81 0.79 0.389 0.455

11 1 0.16 0.15 0.81 0.79 0.389 0.455

12 1 0.17 0.14 0.81 0.79 0.337 0.309

Based on the most recent data from the Jackson monitoring station, MDEQ has recommended an SO2

background concentration of 14 ppb, or 36.65 μg/m3. The 2014 SO2 Monitor Values Report for the Jackson 

monitoring station is attached as Appendix E. SMEPA has used the 14 ppb value as the background

concentration in this analysis.
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Figure 3-5. Land Use within 1 Km and 3 Km Radius around the Jackson Monitoring Station

(Site ID: 280490020)
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4. 1-HOUR SO2 DESIGNATION MODELING RESULTS

4.1. MODELING RESULTS

SMEPA modeled UNIT 1 (AA-001) and UNIT 2 (AA-002) using the actual CEMS data (2012-2014) as hourly 

emission input to the AERMOD model. The Rain CII facility (Table 3-6) was also included as a point source in the 

model. Since the actual emission rates were used for the model, three separate models for 2012 – 2014 were 

created to accurately model the yearly changes in SO2 emissions at the Rain CII facility. Once run separately, the 

modeled results for all three years were averaged together on a receptor-by-receptor basis to maintain 

consistency with the form of the 1-hour SO2 NAAQS. Figure 4-1 below shows the resulting concentration 

contours after the three years were averaged.

Figure 4-1. Contour Plot Showing the Concentration Gradient
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Table 4-1 below shows the receptor with the 4th highest predicted concentration compared to the 1-hour SO2

NAAQS averaged for three years (2012 to 2014).

Table 4-1. 4th - Highest Averaged Modeled Concentration based on Actual Emission Rates (2012-2014)

UTM 

East, m

UTM 

North, m

Modeled 

Concentration, 

μg/m3 (ppb)

Background 

Concentration, 

μg/m3 (ppb)

Modeled 

Concentration 

+ Background, 

μg/m3 (ppb)

1-SO2

NAAQS, 

μg/m3 (ppb)

Pass 

NAAQS? 

(Yes/No)

272,900 3,456,400 111.36 (42.50) 36.65 (13.99) 148.04 (56.49) 196.34 (75) Yes

As seen in Table 4-1, modeled concentrations from actual emissions (along with the background concentration) 

are well below the NAAQS standard. Since the modeled concentration based on the actual emission rates 

from SMEPA and the nearby Rain CII facility are in compliance with the 1-hour SO2 NAAQS, SMEPA has 

demonstrated that the area around the Morrow Plant, including Lamar County, is attainment and should 

be designated as “attainment”.
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5. ELECTRONIC FILES

All of the air quality dispersion modeling analysis electronic data files used to generate the results presented in 

this report are provided in the attached CD. These electronic data files include the following:

> All AERMOD input, output, and plot data files;

> Meteorological files;

> All downwash input and output files;

> Boundary line files;

> AERSURFACE files and NLCD92 map;

> CEMS raw data;

> Hourly input files; and

> Electronic version of the modeling report

The following tables summarize the electronic files included in the attached CD.
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Table 5-1. AERMOD Input and Output File Descriptions for the Air Quality Dispersion Modeling Analysis

Pollutant and Averaging 

Periods File Name AssociatedFiles File Description ReceptorGrid Emission Sources

SO2 (1-hr)

SO2SIP2C12H.zip

SO2SIP2C13H.zip 

SO2SIP2C14H.zip 

Input 

file(*.ami)

Output file, 

(*.aml)

Plot file 

(*.plt)

SO2 Designation Modeling All AA-001, AA-002, and 

Rain CII 

Table 5-2. Meteorological Files Used for the Air Quality Dispersion Modeling Analysis

Level Meteorological File Name Year

Surface KHBG (WBAN:13833) 2012-2014

Profile/Upper 

Air Upper Air (WBAN:03940) 2012-2014

Table 5-3. Other Associated Files

File Name Description

Bpip output file Downwash file

BND.bln Property line file

Aersurface AERSURFACE inputs and output 

SMEPA Modeling Report (082015).pdf Modeling report

HERF-2012, HERF-2013, and HERF-2014 Hourly Emission Rate Files

CEMS Data CEMS Raw Data from SMEPA
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APPENDIX A: MODELING PROTOCOL
SMEPA – R D 

AIR DISPERSION MODELING PROTOCOL

South Mississippi Electric Power Association>

R D Morrow Plant, Lamar County, MS

1-Hour SO2 NAAQS Designation Modeling Protocol

Prepared By:

TRINITY CONSULTANTS

One Galleria Blvd., Suite 1830

Metairie, Louisiana - 70001

(504) 828-5845

June 2, 2015

151902.0007

Environmental solutions delivered uncommonly well
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TABLE OF CONTENTS

1. INTRODUCTION 1-1

2. 1-HOUR SO2 DESINGATION MODELING PROCEDURES 2-1

2.1. Model Selection .........................................................................................................................................................2-1

2.2. Meteorological data .................................................................................................................................................2-1

2.2.1. Surface Data...........................................................................................................................................................................2-1

2.2.2. Upper Air Data.......................................................................................................................................................................2-1

2.2.3. Land Use Analysis.................................................................................................................................................................2-1

2.2.4. AERMET Processing Options............................................................................................................................................2-5

2.3. Coordinate System ...................................................................................................................................................2-5

2.4. Receptor Locations...................................................................................................................................................2-5

2.5. Terrain Elevations....................................................................................................................................................2-5

2.6. Building Influences ..................................................................................................................................................2-6

2.7. SMEPA Emission Sources .......................................................................................................................................2-6

2.8. Emissions Inventories for Nearby Sources......................................................................................................2-7

2.9. Source Contributions and SMEPA Boiler Refinements ...............................................................................2-7

2.10. Background Concentration ................................................................................................................................2-7

APPENDIX A: MDEQ MET DATA GUIDANCE DOCUMENT A
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LIST OF FIGURES

Figure 2-1. Land-use Around the KHBG Met Station (10-KM Radius) 2-3

Figure 2-2. Land-use Around the Morrow Plant (10-KM Radius) 2-4
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LIST OF TABLES

Table 2-1. AERSURFACE Input Parameters 2-2

Table 2-2. SMEPA Model Inputs – Scenario 1 2-6

Table 2-3. SMEPA Model Inputs – Scenario 2 2-6

Table 2-4. Nearby Sources Model Inputs 2-7
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1. INTRODUCTION

The South Mississippi Electric Power Association (SMEPA) owns and operates the R D Morrow Electric Power 

Generating Plant (Morrow Plant) located in Lamar County, Mississippi. The plant is currently operating under 

the Title V Permit No. 1440-00021 issued by the Mississippi Department of Environmental Quality (MDEQ).

On June 2, 2010, U. S. Environmental Protection Agency (U.S. EPA) revised the primary National Ambient Air 

Quality Standards (NAAQS) for sulfur dioxide (SO2) by establishing a 1-hour standard at a level of 75 parts per 

billion (ppb)1, which is equivalent to 196 g/m3. The form of the 1-hour SO2 NAAQS standard is a 3- year 

average of the 99th percentile of the annual distribution of daily maximum 1-hour average concentrations. 

Following the U.S. EPA’s May 2014 publication of the proposed Data Requirements Rule, the U.S. EPA was sued 

for “failing to undertake a certain nondiscretionary duty under the Clean Air Act (“CAA”), 42 U.S.C. §§ 7401-7671q, 

and that such alleged failure is actionable under section 304(a)(2) of the CAA, 42 U.S.C. § 7604(a)(2)”. The lawsuit 

resulted in a Consent Decree that was entered on March 2, 2015 in the U.S. District Court for the Northern 

District of California2. As a result of the Consent Decree, an additional designation phase was added to the two 

designation phases that were already included in the U.S. EPA’s May 2014 proposed Data Requirements Rule. 

The additional phase affects areas with stationary sources that meet specific emission criteria laid out in the 

Consent Decree. The U.S. EPA released a memorandum on March 20, 2015 (referred to herein as the 2015 SO2

Area Designation Guidance) to the Regional Directors clarifying the path forward for states with sources affected 

by the decree.

3

The Consent Decree requires the U.S. EPA to complete a round of SO2 designations for the areas affected by the 

Consent Decree by July 2, 2016. The U.S. EPA is expected to release a final version of the Data Requirements 

Rule around September 2015. It is expected that the Data Requirements Rule will address all three remaining 

phases of the designation process.

The Morrow plant meets the emission criteria laid out in the consent decree. The U.S. EPA has listed the Morrow 

plant as a source exceeding the established threshold with an annual emissions of 3,948 TPY and emission rate 

of 0.63 lbs/MMBTU based on 2012 emissions data.

4 Thus, the U.S. EPA is required to designate the area 

surrounding the morrow plant by July 2, 2016. Because the Consent Decree does not provide sufficient time to 

commission representative ambient air monitors, SMEPA has decided to utilize an air dispersion modeling to 

determine attainment status. Therefore, in accordance with the EPA’s May 2014 proposed Data Requirements 

Rule5, an SO2 designation for the area surrounding the Morrow plant will be based on the predictions of an air 

dispersion model. The U.S. EPA published a draft Technical Assistance Document (TAD) in December 2013 

describing the approach that should be considered when conducting dispersion modeling in support of a 1-hour 

 

1 http://www.epa.gov/air/criteria.html. Final rule signed June 2, 2010

2 http://www.epa.gov/so2designations/pdfs/201503FinalCourtOrder.pdf

3 http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/20150320SO2designations.pdf

4 http://www.epa.gov/airquality/sulfurdioxide/designations/pdfs/sourceareas.pdf

5 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OAR-2013-0711-0001
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SO2 NAAQS designation6 (referred to herein as the 2013 SO2 NAAQS Modeling TAD). To determine the 

attainment status, SMEPA will use following air dispersion modeling scenarios:

SCENARIO 1:

 Use the allowable SO2 emission limit of 1.2 lb/MMBTU;

 Use three (3) years of meteorological data (2012, 2013, and 2014); 

 Use actual stack heights for designation. If the actual height of a stack is greater than the Good 

Engineering Practice (GEP) Stack height, GEP stack height will be used for modeling ; and

 Include near-by sources from the regional inventories provided by the Mississippi Department of 

Environmental Quality.

SCENARIO 2:

 Use the most recent three (3) years of actual emissions (2012, 2013, and 2014);

 Use of three (3) years of meteorological data ( 2012, 2013, and 2014);

 Use actual stack heights for designation. If the actual height of a stack is greater than the Good 

Engineering Practice (GEP) Stack height, GEP stack height will be used for modeling; and

 Include near-by sources from the regional inventories provided by the Mississippi Department of 

Environmental Quality.

For sources with SO2 Continuous Emission Monitoring Systems (CEMS), the CEMS data will be used in Scenario 2 

to characterize emissions. Trinity is planning to conduct the dispersion modeling on behalf of SMEPA to predict 

the SO2 concentrations in the area surrounding the Morrow plant. The modeling will be performed in

accordance with the 2013 SO2 NAAQS Modeling TAD. The remainder of this protocol summarizes modeling

procedures that will be used in the modeling described above.

 

6 http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/SO2ModelingTAD.pdf
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2. 1-HOUR SO2 DESINGATION MODELING PROCEDURES

2.1. MODEL SELECTION

Trinity will perform 1-hour SO2 modeling using EPA’s preferred AERMOD Version 14134 using input files 

developed using Trinity’s BREEZE Software. AERMOD is a steady-state Gaussian dispersion model based on 

planetary boundary layer turbulence structure and scaling concepts, including treatment of both surface and 

elevated sources, and both simple and complex terrain7.

2.2. METEOROLOGICAL DATA

SMEPA proposes to use the meteorological data collected at the Bobby L Chain Municipal Airport Station

(WBAN: 13833), which is approximately 9 miles from the center of the facility. A determination of whether the 

meteorological data from the met station were appropriate for use in SMEPA’s modeling analyses was 

considered by determining whether the data were representative of the site where the Morrow plant is located.

The close proximity of the met station with respect to the plant (less than 9 miles distance), in addition to the 

similarity in the climatology and topography, support that the meteorological conditions at the airport are 

representative of the meteorological conditions at the Morrow plant.

AERMOD-ready meteorological data will be prepared using the latest version of the U.S. EPA’s AERMET 

meteorological processing utility (version 14134). The met data will be generated in accordance with the Met 

support data document as attached in Appendix A

2.2.1. Surface Data

Raw hourly surface meteorological data will be obtained from the U.S. National Climactic Data Center (NCDC) for 

Bobby L Chain Municipal Airport Station (KHBG, WMO ID: 724560) in the standard ISHD format. This data will 

be supplemented with TD-6405 (so-called “1-minute”) wind data from KHBG. The 1-minute wind data will be 

processed using the latest version of the U.S. EPA AERMINUTE pre-processing tool (version 14337). The quality 

of the 1-minute data will be verified by comparison to the hourly ISHD data from KHBG.

2.2.2. Upper Air Data

In addition to surface meteorological data, AERMET requires the use of data from a sunrise-time upper air 

sounding to estimate daytime mixing heights. Upper air data from the nearest U.S. National Weather Service 

(NWS) upper-air balloon station, located in Jackson, Mississippi (WBAN: 03940), will be obtained from the 

National Oceanic and Atmospheric Administration (NOAA) in FSL format.

2.2.3. Land Use Analysis

Parameters derived from the analysis of land-use data (surface roughness, Bowen ratio, and albedo) are also 

required by AERMET. In accordance with U.S. EPA guidance, these values will be determined using the latest 

version of the U.S. EPA AERSURFACE tool (version 13016).8 The AERSUFACE settings that will be used for 

processing are summarized in Table 1 below. The met station coordinates were determined by visually 

 

7 http://www.epa.gov/ttn/scram/dispersion_prefrec.htm#aermod

8 U.S. Environmental Protection Agency. 2013. “AERSURFACE User’s Guide.” EPA-454/B-08-001, Revised 01/16/2013. Available 

Online: http://www.epa.gov/scram001/7thconf/aermod/aersurface_userguide.pdf
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identifying the met station using Google Earth. NLCD 1992 (CONUS) Land Cover data used in AERSURFACE 

processing was obtained from the Multi-Resolution Land Use Consortium (MRLC). 

U.S. EPA guidance dictates that on at least an annual basis, precipitation at a surface site should be classified as 

wet, dry, or average in comparison to the 30-year climatological record at the site. This determination is used to 

adjust the Bowen ratio estimated by AERSURFACE. To make the determination, annual precipitation in each 

modeled year (2012 to 2014) will be compared to the 1981 to 2010 climatological record for KHBG.

9 The 30th

and 70th percentile values of the annual precipitation distribution from 1981 to 2010 will be calculated. Per U.S. 

EPA guidance, each modeled year will be classified for AERSUFACE processing as “wet” if its annual 

precipitation was higher than the 70th percentile value, “dry” if its annual precipitation was lower than the 30th

percentile value, and “average” if it was between the 30th and 70th percentile values. The values to be used in 

this case are summarized in Table 2-1. The values are based on the guidance document attached as Appendix A.

Table 2-1. AERSURFACE Input Parameters

AERSURFACE Parameter Value

Met Station Latitude 31.269483

Met Station Longitude -89.256108

Datum NAD 1983

Radius for surface roughness (km) 1.0

Vary by Sector? Yes

Number of Sectors 12

Temporal Resolution Monthly

Continuous Winter Snow Cover? No

Station Located at Airport? Yes

Arid Region? No

Surface Moisture Classification Average

 

9 National Climactic Data Center. 2010 Local Climatological Data (LCD).
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Figure 2-1. Land-use Around the KHBG Met Station (10-KM Radius)
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Figure 2-2. Land-use Around the Morrow Plant (10-KM Radius)
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2.2.4. AERMET Processing Options

Standard AERMET processing options will be used.

10,11 The options elected will include:

MODIFY keyword for upper air data

THRESH_1MIN 0.5 keyword to provide a lower bound of 0.5 m/s for 1-minute wind data

AUDIT keywords to provide additional QA/QC and diagnostic information

ASOS1MIN keyword to incorporate 1-minute wind data

NWS_HGT WIND 10 keyword to designate the anemometer height as 10 meters

METHOD WIND_DIR RANDOM keyword to correct for any wind direction rounding in the raw ISHD data

METHOD REFLEVEL SUBNWS keyword to allow use of airport surface station data

Default substitution options for cloud cover and temperature data will not be overridden

Default ASOS_ADJ option for correction of truncated wind speeds will not be overridden

ADJ_U* beta option will not be used

2.3. COORDINATE SYSTEM

In all modeling input and output files, the locations of emission sources, structures, and receptors will be 

represented in Zone 16 of the Universal Transverse Mercator (UTM) coordinate system using datum World 

Geodetic System (WGS) 1984, which is comparable to the North American Datum 1983 (NAD83). The Morrow 

plant is approximately centered at UTM, Zone 16, coordinates 272,009 meters East and 3,456,266 meters North.

The base elevation of the facility is approximately 79 meters above mean sea level.

2.4. RECEPTOR LOCATIONS 

The dispersion modeling will use a combination of a Cartesian grid system centered on the Morrow plant and 

discrete receptor points along the facility’s fence line. Receptors will be placed at 25-meter intervals along the 

fence line, 100-meter intervals out to a distance of 2.5 kilometers (km) and at 500-meter intervals out to either 

10 km or further if need to encompass areas modeling above the 1-hour SO2 Significant Impact Level (SIL) of 7.5 

g/m3 or if a significant concentration gradient is found at or near the edge of the initially defined receptor grid. 

Based on the 2013 SO2 NAAQS Modeling TAD and the 2015 SO2 Area Designation Guidance, the receptor grid 

will be adjusted to include only those locations where it is feasible to place a monitor.

2.5. TERRAIN ELEVATIONS

The terrain elevation for each receptor, building, and emission source will be determined using USGS 1/3 arcsecond National Elevation Data (NED). The NED, obtained from the USGS, has terrain elevations at 10-meter 

intervals. Using the AERMOD terrain processor, AERMAP (version 11103), the terrain height for each receptor, 

building, and emission source included in the model will be determined by assigning the interpolated height 

from the digital terrain elevations surrounding each source.

In addition, AERMAP will be used to compute the hill height scales for each receptor. AERMAP searches all NED 

points for the terrain height and location that has the greatest influence on each receptor to determine the hill 

 

10

 Fox, Tyler, U.S. Environmental Protection Agency. 2013. “Use of ASOS Meteorological Data in AERMOD Dispersion 

Modeling.” Available Online: http://www.epa.gov/ttn/scram/guidance/clarification/20130308_Met_Data_Clarification.pdf

11 U.S. Environmental Protection Agency. 2014. “User’s Guide for the AERMOD Meteorological Preprocessor (AERMET)”. 

EPA-454/B-03-002, November 2004).
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height scale for that receptor. AERMOD then uses the hill height scale in order to select the correct critical 

dividing streamline and concentration algorithm for each receptor.

2.6. BUILDING INFLUENCES

The U.S. EPA’s Building Profile Input Program (BPIP) with Plume Rise Model Enhancements (PRIME) (version 

04274), will be used to account for Morrow plant building downwash influences in the model. The purpose of a 

building downwash analysis is to determine if the plume discharged from a stack will become caught in the 

turbulent wake of a building (or other structure), resulting in downwash of the plume. The downwash of the 

plume can result in elevated ground‐level concentrations of SO2. At this time, SMEPA is not planning to include 

any buildings from nearby sources in the model.

2.7. SMEPA EMISSION SOURCES

There are two boilers at the Morrow plant that will be included in the modeling. The stacks for the boilers will 

be modeled as point sources. Table 2-2 below summarizes the existing stack parameters for both boilers for 

Scenario 1. Table 2-3 below summarized the stack parameters for Scenario 2. If Scenario 1 does not show 

concentrations below the NAAQS threshold, Scenario 2 will be completed by using CEMS data. The existing 

stack parameters will be modeled in the initial modeling conducted in accordance with the 2013 SO2 Modeling 

TAD. 

Table 2-2. SMEPA Model Inputs – Scenario 1

Emission 

Point

UTM East

(m)*

UTM North

(m)*

Stack 

Height 

(ft.)

Stack 

Diameter 

(ft.)

Exit 

Velocity 

(ft./s)

Exit 

Temperature 

(F)

Emission 

Rate 

(lb/hr)

AA-001 271925.3 3456230.6 405.2 16.7 51.2 180 3210

AA-002 271975.6 3456229.4 405.2 16.7 55.3 180 3210

*UTM Zone 16, NAD 83

Table 2-3. SMEPA Model Inputs – Scenario 2

Emission 

Point

UTM East

(m)*

UTM North

(m)*

Stack 

Height 

(ft.)

Stack 

Diameter 

(ft.)

Exit 

Velocity 

(ft./s)

Exit 

Temperature 

(F)

Emission 

Rate 

(lb/hr)

AA-001 271925.3 3456230.6 405.2 16.7 CEMS CEMS CEMS

AA-002 271975.6 3456229.4 405.2 16.7 CEMS CEMS CEMS

*UTM Zone 16, NAD 83
SMEPA – R D Morrow Plant | 1–Hour SO2 NAAQS Designation Modeling Protocol

Trinity Consultants 2-7

2.8. EMISSIONS INVENTORIES FOR NEARBY SOURCES

Other sources of SO2 emissions in the area surrounding the Morrow plant will be included in the model. SMEPA 

will request for the emissions inventory from the MDEQ. Based on the emissions inventory data provided by the 

MDEQ, SMEPA will incorporate nearby potential sources in the model for SO2 designation.

Table 2-4. Nearby Sources

Source

Distance 

from 

SMEPA 

(km)

UTM 

East

(m)*

UTM 

North

(m)*

Stack 

Height 

(ft.)

Stack 

Diameter 

(ft.)

Exit 

Velocity

(ft./s)

Exit 

Temperature 

(F)

Plantwide 

Emissions

(tpy)

Rain CII Carbon,

LLC 3.85 272603 3451824 114.0 8.7 16.9 405 746.14

Leaf River 

Cellulose, LLC 33.42 304943 3457831 20.0 1.5 15.0 250 33.42

Transcontinental 

Gas Pipeline Co. 42.15 270855 3497683 13.0 2.0 112.0 750 42.13

*UTM Zone 16, NAD 83

2.9. SOURCE CONTRIBUTIONS AND SMEPA BOILER REFINEMENTS

Trinity will run the model using the “MAXDCONT” option. The use of MAXDCONT necessitate the model to 

generate output that allows both the cumulative concentrations as well as individual contributions from SMEPA

and nearby sources to be analyzed. If initial modeling shows concentrations above the 1-hours SO2 NAAQS, 

additional modeling of various compliance scenarios specific to the Morrow plant sources will be conducted. 

Steps that will be considered in the modeling scenarios are as follows:

1. Initially, the output from the MAXDCONT processing will be filtered to show each event where the 

combined impact from both the Morrow plant and nearby sources is over the NAAQS.

2. Each event found to be over the NAAQS will then be will be analyzed further to determine the impacts 

attributable to the Morrow plant and the impacts attributable to nearby sources. 

3. If SMEPA is found to individually model over the NAAQS, the plant will focus on a strategy to reduce its 

own impact below the NAAQS. The plant does not intend to “do more than their share” to reduce SO2

concentrations in the area surrounding SMEPA.

2.10. BACKGROUND CONCENTRATION

SMEPA will work with MDEQ to develop a 1-hour SO2 background concentration that is representative of the 

background concentration in the vicinity of the Morrow plant. SMEPA will incorporate the agreed upon 

background concentration in the model.
SMEPA – R D Morrow Plant | 1–Hour SO2 NAAQS Designation Modeling Report

Trinity Consultants

APPENDIX B: MS AERMOD READY MET FILES - SUPPORTING DOCUMENTATION
1MS AERMOD Ready 

Met Files

Supporting Documentation, July 1, 2014Mississippi Department of Environmental Quality www.deq.state.ms.usBruce Ferguson
2

MS AERMOD Ready Met Files

Supporting Documentation

The Mississippi Department of Environmental Quality (MDEQ) has posted preprocessed 

meteorological files for use with the US EPA regulatory model AERMOD on the MDEQ 

website. The posting of these files in no way dictates their use nor supplants the use of 

professional judgment in determining whether the files are appropriate for any 

particular application. This report documents the development of the preprocessed 

files.

Integrated surface data was obtained from NCDC in DS3505 format 

(ftp://ftp.ncdc.noaa.gov/pub/data/noaa). Radiosonde observations were obtained from 

the NOAA/ESRL Radiosonde Database (http://www.esrl.noaa.gov/raobs/). When 

available, 1-minute ASOS wind data was included in the processing of the met data 

through the use of AERMINUTE – Version 11325. One-minute data was obtained 

through the National Climatic Data Center (NCDC) 

(ftp://ftp.ncdc.noaa.gov/pub/data/asos-onemin/).

When applying the AERMET meteorological processor to prepare the meteorological 

data for the AERMOD model, the user must determine appropriate values for three 

surface characteristics: surface roughness length {zo}, albedo {r}, and Bowen ratio {Bo}. 

AERSURFACE (dated 13016), a tool that processes land cover data to determine these 

surface characteristics for use in AERMET, was used in the processing of the posted met 

files.

Aersurface Monthly Seasonal Designations

Winter with continuous snow on the ground does not occur in Mississippi; therefore this

seasonal designation was not used in the AERSURFACE input files. The AERMET user’s

guide defines spring as the 1-2 months after the last killing frost. Freeze/Frost

occurrence data was used to determine the beginning of spring using the 50 percent

probability date for 28o F. Likewise, the fall 50 percent probability date for 28o F was

used to determine the late autumn after frost and harvest seasonal designation. These 

dates are were determined from Frost/Freeze Data 1971-2000 (CLIM20-01), NCDC and

indicate the date on which there is a 50% probability that a freeze date may be later in 
3

the spring or earlier in the fall. Dates for the stations within a climate division were

averaged.

Months that fall between the fall and spring dates (rounded to beginning or end of

month, whichever was closer) were considered to be “Late autumn after frost and

harvest.”

Midsummer with lush vegetation was assumed to be months with a monthly normal

temperature above 70o F. Monthly normal temperatures were taken from

“Climatography of the US No. 85, Divisional Normals and Standard Deviations of

Temperature, Precipitation, and Heating and Cooling Degree Days 1971-2000”.

Spring months were considered to be those between the determined Late Autumn

months and the Midsummer months. Autumn months were considered to be those

between the determined Midsummer months and the Late Autumn months. Seasonal

designations used are listed in Table 2.

Surface Moisture

Surface Moisture was determined using US Climate Normals. Table 3 lists the 

precipitation normal and standard deviation for the Mississippi Divisions. Surface 

moisture was considered to be average if the rainfall was within one standard deviation 

of the averages presented in Table 3. Surface moisture was considered to be dry if the 

precipitation was more than one standard deviation below the normal and wet if the 

precipitation was more than one standard deviation above the normal. Table 4 through 

Table 11 summarize the precipitation for the years 2006 through 2013. Dry months are 

highlighted in orange and wet months are highlighted in blue. The surface moisture 

designation for the aersurface file was determined by the most months with the same 

determination of average, dry or wet. The moisture designation used in aersurface is 

indicated outside each division row. The surface moisture was determined to be average 

for all time periods with the exception of 2007 for the Northeast Division and 2011 for 

the Coastal Division, which were determined to be dry. The Coastal Division 

determination was used in the processing of the Mobile station, although this station is 

not located in the Mississippi Coastal Division.

AERSURFACE Inputs

Locations of the monitoring stations included in the aersurface files were checked by 

reviewing aerial photography in Google Earth and Bing Bird’s Eye View. The locations 

were also cross referenced to the “ASOS Tropical Cyclone Wind Exposure 
4

Documentation Project.” No attempts were made to correct aersurface runs for 

changes in land use after the 1992 determination. 

The AERSURFACE inputs were selected to be consistent with the “AERMOD 

Implementation Guide.” Twelve sectors were used for the determination and the 

surface parameters were selected as described above. The standard AERSURFACE input 

file used was as follows:

[NLCD 1992File] ** Land use data file

[AERSURFACE.out] ** Output file with sfc values for AERMET Stage 3 

LATLON ** Coordinate type (UTM, LATLON)

[surface station lat] ** Latitude [obtained from Table 1]

[surface station long] ** Longitude [obtained from Table 1] 

NAD83 ** Datum

1.0 ** Study radius for surface roughness (km) 

Y ** Vary by sector? (Y/N)

12 ** Number of sectors

M ** Temporal resolution (A=ANNUAL, M=MONTHLY, S=SEASONAL)

N ** Continuous snow cover at least one month? (Y/N)

Y ** Reassign months to seasons? (Y/N)

[Table 2] ** Late autumn after frost and harvest, or winter with no snow

[Table 2] ** Transitional spring (partial green coverage, short annuals)

[Table 2] ** Midsummer with lush vegetation

[Table 2] ** Autumn with unharvested cropland

Y ** Airport? (Y/N)

N ** Arid region? (Y/N)

[varied with rainfall] ** Surface Moisture (A=Average, W=Wet, D=Dry)

AERMET 14134 Inputs

Integrated surface data in DS3505 format was obtained from NCDC for each station. 

Upper air data was downloaded in FSL format from the NOAA/ESRL Radiosonde 

Database. Observations obtained from Slidell, LA were used for the Mobile station and 

stations located in the Coastal Division. Observations obtained from Jackson, MS were 

used for all other divisions.

When available, ASOS 1-minute data was incorporated using AERMINUTE version 

11325. The threshold wind speed was set at 0.5 m/s in Stage 3 when ASOS 1-minute 

data was used. The SUBNWS parameter was also used with ASOS 1-minute data to 

replace wind data from the standard NWS format. The SUB_CC and SUB_TT parameters 

were indicated in the stage 3 input files. The AERMET user’s guide indicates that these 

are default parameters unless the application involves both NWS and ONSITE surface 

data.

Example input files for the Jackson, MS station are presented below.
5

Stage 1

JOB

 REPORT KJAN_09.RP1

 MESSAGES KJAN_09.MG1

UPPERAIR

 DATA "C:\meterological Data\Mississippi\Jackson.fsl" FSL

 EXTRACT KJAN_09.UAX

 QAOUT KJAN_09.UQA

 XDATES 2009/01/01 TO 2009/12/31

** Station: JACKSON/THOMPSON FIELD, MS

 LOCATION 3940 32.320N 90.070W 6

 AUDIT UADD UADS UAHT UALR UAPR UASS UATD UATT UAWD UAWS

SURFACE

** Location of the Surface Data File

** C:\meterological Data\Mississippi\KJAN\722350-03940-2009\722350-03940-2009

 DATA 722350-03940-2009\722350-03940-2009 ISHD

 EXTRACT KJAN_09.SAX

 QAOUT KJAN_09.SQA

 XDATES 2009/01/01 TO 2009/12/31

** Station: JACKSON/THOMPSON FIELD, MS

 LOCATION 3940 32.320N 90.078W 6 89.00

 AUDIT ACHT ALC1 ALC2 ALC3 ALC4 ALC5 ALC6 ASKY CLHT DPTP HZVS PRCP PRES

 AUDIT PWTH PWVC RHUM SLVP TMPD TMPW TSKC WDIR WSPD

Stage 2

JOB

 REPORT KJAN_09.RP2

 MESSAGES KJAN_09.MG2

UPPERAIR

 QAOUT KJAN_09.UQA

SURFACE

 QAOUT KJAN_09.SQA
6

** Location of the Hourly Wind Data File

** C:\meterological Data\Mississippi\KJAN\KJAN_09_AERMIN\AERMINUTE_hour.dat

 ASOS1MIN KJAN_09_AERMIN\AERMINUTE_hour.dat

MERGE

 OUTPUT KJAN_09.MRG

 XDATES 2009/01/01 TO 2009/12/31

Stage 3

JOB

 REPORT KJAN_09.RP3

 MESSAGES KJAN_09.MG3

METPREP

 DATA KJAN_09.MRG

 MODEL AERMOD

 OUTPUT aermet.sfc

 PROFILE aermet.pfl

 XDATES 2009/01/01 TO 2009/12/31

 METHOD REFLEVEL SUBNWS

 METHOD WIND_DIR RANDOM

 METHOD CCVR SUB_CC

 METHOD TEMP SUB_TT

 THRESH_1MIN 0.50

 NWS_HGT WIND 10.00

** Primary Surface Characteristics

** Location of the AERSURFACE Output File

** C:\meterological Data\Mississippi\KJAN\KJAN_09_AERSURF1\AERSURFACE.OUT

 AERSURF KJAN_09_AERSURF1\AERSURFACE.OUT

Data Completeness

The process met files were used in test runs with AERMOD version 14134. The files 

were run by quarter and the percentage of missing hours noted from the AERMOD 

output file. Table 12 summarizes the results of the completeness check. Additional years 

of met data were processed for each site until five years of complete data, by quarter, 

were obtained. For the majority of the sites, the five years of data is by calendar year. 

For some sites, four consecutive quarters of complete data were available across 

calendar years. The data was grouped by quarters for these sites and the naming 
7

convention for the processed data indicates that the data is across multiple calendar 

years.

Combining Met Files

All of the met data was processed by calendar year. For cases where four consecutive 

complete quarters by calendar year were not available, the data was combined using a 

text editor from the previously processed data. For the calendar year 2010, the stations 

KGLH, KGPT, KGWO and KHBG had changes in the USAF number. For these stations, the 

surface data was contained in two separate files for the 2010 calendar year. The 

location was identical in each of the two files for each station. The partial years for 

these stations were processed separately and combined after processing to obtain a 

complete calendar year.

Processed met files that contain quarters from separate calendar years can be identified 

in the naming convention of the files. For example, the file KGTR_06_07.sfc contains on 

full year of data from both calendar years 2006 and 2007. For stations which had 

separate NCDC files for the same calendar year, the file name contains a “c” at the end 

to indicate that these files were combined after processing individual surface files. For 

example, KGWO_10c.SFC is a combination of the individual ISHD files “722359-13978-

2010” and “747580-13978-2010”. 
8

Table 1 – Station List

City Station Name WBAN

INT CALL

Latitude Longitude

AerminuteAvailableAnemometerHeight (m)

GREENVILLE MID DELTA REGIONAL AIRPORT 13939 KGLH 33.477228 -90.984658 No 10

GREENWOOD GREENWOOD-LEFLORE AIRPORT 13978 KGWO 33.496194 -90.089419 Yes 10

GULFPORT GULFPORT-BILOXI INTERNATIONAL AIRPORT 93874 KGPT 30.412000 -89.081000 Yes 10

HATTIESBURG BOBBY L CHAIN MUNICIPAL AIRPORT 13833 KHBG 31.269483 -89.256108 Yes 10

JACKSON HAWKINS FIELD AIRPORT 13927 KHKS 32.337572 -90.221397 Yes 10

JACKSON JACKSON INTERNATIONAL AIRPORT 3940 KJAN 32.319836 -90.077756 Yes 10

McCOMB MC COMB/PIKE COUNTY/JOHN E LEWIS FIELD AIRPORT 93919 KMCB 31.182278 -90.472025 Yes 10

MERIDIAN KEY FIELD AIRPORT 13865 KMEI 32.334861 -88.750728 Yes 10

PASCAGOULA TRENT LOTT INTERNATIONAL AIRPORT 53858 KPQL 30.463058 -88.531556 Yes 7.92

TALLULAH/VICKSBURG VICKSBURG/TALLULAH REGIONAL AIRPORT 3996 KTVR 32.348000 -91.030000 Yes 10

TUPELO TUPELO REGIONAL AIRPORT 93862 KTUP 34.262131 -88.771161 Yes 10

COLUMBUS GOLDEN TRIANGLE RGNL 53893 KGTR 33.456278 -88.592656 No 10

COLUMBUS COLUMBUS AFB 13825 KCMB 33.652258 -88.457136 No 10

NATCHEZ NATCHEZ/HARDY(AWOS) 3961 KHEZ 31.615919 -91.297267 No 10

HATTIESBURG HATTIESBURG LAUREL 53808 KPIB 31.465756 -89.333464 No 10

METCALFE TUNICA MUNI 23903 KUTA 34.676575 -90.343956 No 10

MEMPHIS MEMPHIS INTL ARPT 13893 KMEM 35.036472 -89.971861 Yes 10

MOBILE MOBILE/BATES FIELD 13894 KMOB 30.688222 -88.245969 Yes 10
9

Table 2 - AERSURFACE Monthly Designations

Station

Months Normal

above 70o

F

Spring 50%

Probability

@ 28o F.

Fall 50%

Probability

@ 28o F

Late

Autumn

Months

Transitional

Spring

Months

Midsummer

Months

Autumn

Months

MS-01 Upper Delta May-Sep 3-Mar 21-Nov 12, 1, 2 3,4 5,6,7,8,9 10,11

MS-02 North Central June-Sep 20-Mar 9-Nov 11,12,

1, 2,3 4,5 6,7,8,9 10

MS-03 Northeast June-Sep 19-Mar 12-Nov 11,12,

1, 2,3 4,5 6,7,8,9 10

MS-04 Lower Delta May-Sep 23-Feb 26-Nov 12, 1, 2 3,4 5,6,7,8,9 10,11

MS-05 Central May-Sep 11-Mar 15-Nov 12, 1,2 3,4 5,6,7,8,9 10,11

MS-06 East Central May-Sep 10-Mar 15-Nov 12, 1,2 3,4 5,6,7,8,9 10,11

MS-07 Southwest May-Sep 25-Feb 26-Nov 12, 1, 2 3,4 5,6,7,8,9 10,11

MS-08 South Central May-Sep 27-Feb 25-Nov 12, 1, 2 3,4 5,6,7,8,9 10, 11

MS-09 Southeast May-Sep 2-Mar 24-Nov 12, 1, 2, 3,4 5,6,7,8,9 10,11

MS-10 Coastal May-Sep 12-Feb 16-Dec 1 2,3,4 5,6,7,8,9 10,11,12
10

Table 3 - Divisional Normals and Standard Deviations of Precipitation (inches)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta AVERAGE 4.94 4.53 5.71 5.49 5.46 4.97 4.07 2.59 3.03 3.25 5.48 5.58 55.1

71-00 STD DEV 2.72 2.64 2.57 3.19 2.65 2.29 2.07 1.54 1.7 2.17 2.75 3.59 10.01

MS-02 North Central AVERAGE 5.13 4.48 5.86 5.45 5.5 4.85 4.28 3.26 3.56 3.45 5.34 5.81 56.97

71-00 STD DEV 2.6 2.34 2.75 3.05 2.71 2.58 2.1 1.64 1.86 1.97 2.62 3.51 9.58

MS-03 Northeast AVERAGE 5.28 4.73 6.32 5.32 5.82 4.52 4.25 3.22 3.92 3.44 5.43 6.17 58.42

71-00 STD DEV 2.93 2.23 3.18 2.87 3.55 2.33 1.82 1.65 2.29 1.83 2.47 3.88 10.38

MS-04 Lower Delta AVERAGE 5.67 4.71 6.16 5.67 5.59 4.32 4.36 2.71 3.07 3.7 5.3 5.91 57.17

71-00 STD DEV 3.16 2.27 2.8 3.54 2.83 2 2.2 1.7 1.26 2.59 2.59 3.82 10.23

MS-05 Central AVERAGE 5.92 4.95 6.32 5.83 5.21 3.97 4.57 3.4 3.45 3.56 5.3 5.79 58.27

71-00 STD DEV 3.11 2.31 2.71 3.7 2.82 1.8 1.93 1.52 1.48 2.42 2.38 3.05 9.76

MS-06 East Central AVERAGE 5.92 4.97 6.26 5.65 5.13 4.34 4.5 3.32 3.61 3.4 5.08 5.34 57.52

71-00 STD DEV 2.78 2.35 3.1 3.48 2.91 2.14 2.08 1.52 2.07 2.18 2.26 2.77 11.21

MS-07 Southwest AVERAGE 6.41 5.21 6.51 6 5.44 4.67 4.54 4.02 3.81 3.62 5.13 6.01 61.37

71-00 STD DEV 3.34 2.68 2.61 3.85 2.79 2.25 1.66 1.85 1.64 2.62 2.39 2.79 8.95

MS-08 South Central AVERAGE 6.53 5.33 6.51 5.88 5.62 4.62 5.26 4.49 4.08 3.52 4.96 5.67 62.47

71-00 STD DEV 2.85 2.78 2.68 3.81 2.96 2.31 2.05 2.18 2.04 2.39 2.13 2.76 9.36

MS-09 Southeast AVERAGE 6.39 5 6.56 5.38 4.9 4.06 5.42 3.88 4.07 3.28 5.01 5.14 59.09

71-00 STD DEV 2.78 2.35 2.66 2.94 2.73 1.63 2.09 1.66 2.41 2.35 2.28 2.31 8.88

MS-10 Coastal AVERAGE 6.33 5.55 6.52 5.14 5.74 4.94 6.86 5.69 5.71 3.18 5.04 4.98 65.68

71-00 STD DEV 3.96 3.08 2.48 3.56 3.6 2.17 2.87 2.55 4.35 2.42 2.78 1.82 11.48

Excerpted from: CLIMATOGRAPHY OF THE UNITED STATES NO. 85
11

Table 4 -- CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2006 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta Precip. 10.55 4.59 3.97 4.96 5.36 2.41 0.92 3.49 3.87 4.48 4.14 7.13 55.87 A

2006 Depart. 5.61 0.06 -1.74 -0.53 -0.1 -2.56 -3.15 0.9 0.84 1.23 -1.34 1.55 0.77

MS-02 North Central Precip. 8.56 4.81 3.94 4.39 4.69 2.74 1.7 3.81 5.27 4.22 3.97 5.7 53.8 A

2006 Depart. 3.43 0.33 -1.92 -1.06 -0.81 -2.11 -2.58 0.55 1.71 0.77 -1.37 -0.11 -3.17

MS-03 Northeast Precip. 7.65 4.5 3.3 4.89 4.55 1.7 1.97 2.09 5.95 5.32 4.28 4.87 51.07 A

2006 Depart. 2.37 -0.23 -3.02 -0.43 -1.27 -2.82 -2.28 -1.13 2.03 1.88 -1.15 -1.3 -7.35

MS-04 Lower Delta Precip. 6.69 7.16 5.22 3.75 3.1 2.19 1.24 2.43 3.58 9.46 2.67 6.58 54.07 A

2006 Depart. 1.02 2.45 -0.94 -1.92 -2.49 -2.13 -3.12 -0.28 0.51 5.76 -2.63 0.67 -3.1

MS-05 Central Precip. 6.98 8.61 4.48 2.35 2.75 2.02 2.54 2.51 4.42 9.57 2.76 5.51 54.5 A

2006 Depart. 1.06 3.66 -1.84 -3.48 -2.46 -1.95 -2.03 -0.89 0.97 6.01 -2.54 -0.28 -3.77

MS-06 East Central Precip. 6.62 8.02 4.46 3.03 3.98 1.16 2.88 2.57 4.28 8.91 3.89 5.28 55.08 A

2006 Depart. 0.7 3.05 -1.8 -2.62 -1.15 -3.18 -1.62 -0.75 0.67 5.51 -1.19 -0.06 -2.44

MS-07 Southwest Precip. 5.25 6.9 4.24 3.42 3.94 1.38 5.21 3.97 1.97 9.04 2.5 5.85 53.67 A

2006 Depart. -1.16 1.69 -2.27 -2.58 -1.5 -3.29 0.67 -0.05 -1.84 5.42 -2.63 -0.16 -7.7

MS-08 South Central Precip. 5.47 5.88 3.67 3.4 3.56 1.22 4.9 5.34 3.68 8.93 4.28 6.49 56.82 A

2006 Depart. -1.06 0.55 -2.84 -2.48 -2.06 -3.4 -0.36 0.85 -0.4 5.41 -0.68 0.82 -5.65

MS-09 Southeast Precip. 4.18 6.47 3.54 2.89 5.02 1.78 5.06 4.5 2.7 5.29 4.27 6.56 52.26 A

2006 Depart. -2.21 1.47 -3.02 -2.49 0.12 -2.28 -0.36 0.62 -1.37 2.01 -0.74 1.42 -6.83

MS-10 Coastal Precip. 2.84 3.18 0.41 4.21 1.55 2.23 4.74 6.48 5.08 4.95 5.7 7.4 48.77 A

2006 Depart. -3.49 -2.37 -6.11 -0.93 -4.19 -2.71 -2.12 0.79 -0.63 1.77 0.66 2.42 -16.91
12

Table 5 - - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2007 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta Precip. 5.77 2.11 0.86 3.88 3 3.4 7.48 0.71 2.7 5.08 2.09 4.44 41.52 A

2007 Depart. 0.83 -2.42 -4.85 -1.61 -2.46 -1.57 3.41 -1.88 -0.33 1.83 -3.39 -1.14 -13.58

MS-02 North Central Precip. 4.81 2.38 0.82 3.46 2.31 4.08 6.12 1.17 2.73 6.62 2.23 4.79 41.52 A

2007 Depart. -0.32 -2.1 -5.04 -1.99 -3.19 -0.77 1.84 -2.09 -0.83 3.17 -3.11 -1.02 -15.45

MS-03 Northeast Precip. 4.76 2.38 1.61 2.63 1.51 2.74 6.1 1.38 3.32 7.4 2.9 4.45 41.18 D

2007 Depart. -0.52 -2.35 -4.71 -2.69 -4.31 -1.78 1.85 -1.84 -0.6 3.96 -2.53 -1.72 -17.24

MS-04 Lower Delta Precip. 4.81 2.29 0.58 3.5 2.92 3.39 7.89 1.61 4.94 4.33 2.37 3.38 42.01 A

2007 Depart. -0.86 -2.42 -5.58 -2.17 -2.67 -0.93 3.53 -1.1 1.87 0.63 -2.93 -2.53 -15.16

MS-05 Central Precip. 4.98 2.46 0.78 2.59 2.72 2.86 7.16 1.4 4.86 3.06 1.89 3.21 37.97 A

2007 Depart. -0.94 -2.49 -5.54 -3.24 -2.49 -1.11 2.59 -2 1.41 -0.5 -3.41 -2.58 -20.3

MS-06 East Central Precip. 4.02 2.87 0.69 2.69 1.2 2.56 5.56 2.28 3.62 4.3 2.23 2.59 34.61 A

2007 Depart. -1.9 -2.1 -5.57 -2.96 -3.93 -1.78 1.06 -1.04 0.01 0.9 -2.85 -2.75 -22.91

MS-07 Southwest Precip. 6.42 2.54 0.83 3.4 2.5 2.97 8.52 2.27 5.28 2.54 2.81 4.34 44.42 A

2007 Depart. 0.01 -2.67 -5.68 -2.6 -2.94 -1.7 3.98 -1.75 1.47 -1.08 -2.32 -1.67 -16.95

MS-08 South Central Precip. 4.91 2.25 0.8 4.52 2.61 3.65 9.1 3.62 3.18 3.58 2.12 4.89 45.23 A

2007 Depart. -1.62 -3.08 -5.71 -1.36 -3.01 -0.97 3.84 -0.87 -0.9 0.06 -2.84 -0.78 -17.24

MS-09 Southeast Precip. 4.14 2.64 0.55 5.28 2.53 4.23 7.25 3.02 3.26 4.3 1.46 4.07 42.73 A

2007 Depart. -2.25 -2.36 -6.01 -0.1 -2.37 0.17 1.83 -0.86 -0.81 1.02 -3.55 -1.07 -16.36

MS-10 Coastal Precip. 4.14 2.5 1.51 4.95 4.3 4.5 8.47 5.13 3.5 8.87 2.15 6.54 56.56 A

2007 Depart. -2.19 -3.05 -5.01 -0.19 -1.44 -0.44 1.61 -0.56 -2.21 5.69 -2.89 1.56 -9.12
13

Table 6 - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2008 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta Precip. 2.72 4.49 5.3 8.45 8.16 1.38 1.5 7.33 3.86 3.64 2.29 7.71 56.83 A

2008 Depart. -2.22 -0.04 -0.41 2.96 2.7 -3.59 -2.57 4.74 0.83 0.39 -3.19 2.13 1.73

MS-02 North Central Precip. 3.13 3.61 7.91 7.19 7.97 2.59 2.19 6.26 3.23 4.72 2.69 9.04 60.53 A

2008 Depart. -2 -0.87 2.05 1.74 2.47 -2.26 -2.09 3 -0.33 1.27 -2.65 3.23 3.56

MS-03 Northeast Precip. 2.11 4.21 4.91 6.31 8.09 1.11 2.61 7.46 3.24 4.76 3.13 10.34 58.28 A

2008 Depart. -3.17 -0.52 -1.41 0.99 2.27 -3.41 -1.64 4.24 -0.68 1.32 -2.3 4.17 -0.14

MS-04 Lower Delta Precip. 2.92 5.43 3.28 7.41 7.14 0.85 2.25 8.47 8 1.86 2.62 9.71 59.94 A

2008 Depart. -2.75 0.72 -2.88 1.74 1.55 -3.47 -2.11 5.76 4.93 -1.84 -2.68 3.8 2.77

MS-05 Central Precip. 2.95 6.43 3.3 6.67 7.03 1.58 3.28 9.28 5.5 2.2 2.82 10.47 61.51 A

2008 Depart. -2.97 1.48 -3.02 0.84 1.82 -2.39 -1.29 5.88 2.05 -1.36 -2.48 4.68 3.24

MS-06 East Central Precip. 3.59 7.08 3.72 5.67 4.79 1.44 3 8.97 3.94 2.89 2.4 10.15 57.64 A

2008 Depart. -2.33 2.11 -2.54 0.02 -0.34 -2.9 -1.5 5.65 0.33 -0.51 -2.68 4.81 0.12

MS-07 Southwest Precip. 4.44 6.56 3.74 3.77 4.95 2.61 1.87 11.58 10.26 1.78 5.12 8.08 64.76 A

2008 Depart. -1.97 1.35 -2.77 -2.23 -0.49 -2.06 -2.67 7.56 6.45 -1.84 -0.01 2.07 3.39

MS-08 South Central Precip. 6.29 5.46 4.17 3.94 4.67 3.26 2.3 7.6 8.01 1.63 4.88 6.71 58.92 A

2008 Depart. -0.24 0.13 -2.34 -1.94 -0.95 -1.36 -2.96 3.11 3.93 -1.89 -0.08 1.04 -3.55

MS-09 Southeast Precip. 6.44 6.13 3.31 4.09 5.05 3.3 3.65 8.43 6.06 1.73 4.47 6.19 58.85 A

2008 Depart. 0.05 1.13 -3.25 -1.29 0.15 -0.76 -1.77 4.55 1.99 -1.55 -0.54 1.05 -0.24

MS-10 Coastal Precip. 7.06 4.95 3.37 6.44 5.46 5.93 3.6 8.65 7.38 1.35 2.16 2.65 59 A

2008 Depart. 0.73 -0.6 -3.15 1.3 -0.28 0.99 -3.26 2.96 1.67 -1.83 -2.88 -2.33 -6.68
14

Table 7 - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2009 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta Precip. 2.61 3.51 6.48 4.19 11.83 2.91 8.96 1.17 8.6 10.82 2.57 6.68 70.33 A

2009 Depart. -2.33 -1.02 0.77 -1.3 6.37 -2.06 4.89 -1.42 5.57 7.57 -2.91 1.1 15.23

MS-02 North Central Precip. 2.63 3.85 5.37 4.01 10.19 3.18 10.92 2.01 7.17 9.68 2.36 6.17 67.54 A

2009 Depart. -2.5 -0.63 -0.49 -1.44 4.69 -1.67 6.64 -1.25 3.61 6.23 -2.98 0.36 10.57

MS-03 Northeast Precip. 3.19 3.51 5.86 2.82 8.4 2.21 6.89 3.98 10.49 10.55 2.32 5.11 65.33 A

2009 Depart. -2.09 -1.22 -0.46 -2.5 2.58 -2.31 2.64 0.76 6.57 7.11 -3.11 -1.06 6.91

MS-04 Lower Delta Precip. 3.87 1.81 6.95 2.67 11.34 0.55 10.28 3.27 7.41 14.94 1.79 5.08 69.96 A

2009 Depart. -1.8 -2.9 0.79 -3 5.75 -3.77 5.92 0.56 4.34 11.24 -3.51 -0.83 12.79

MS-05 Central Precip. 5.02 3.3 8.31 2.09 10.81 1.2 9.43 2.85 7.84 11.94 1.53 6.22 70.54 A

2009 Depart. -0.9 -1.65 1.99 -3.74 5.6 -2.77 4.86 -0.55 4.39 8.38 -3.77 0.43 12.27

MS-06 East Central Precip. 5.8 5.7 8.09 3.39 8.79 2.86 6.17 4.65 11.74 10.39 1.74 6.3 75.62 A

2009 Depart. -0.12 0.73 1.83 -2.26 3.66 -1.48 1.67 1.33 8.13 6.99 -3.34 0.96 18.1

MS-07 Southwest Precip. 3.5 3.58 9.83 4.09 4.65 0.57 6.67 3.59 5.48 11.32 0.97 8.63 62.88 A

2009 Depart. -2.91 -1.63 3.32 -1.91 -0.79 -4.1 2.13 -0.43 1.67 7.7 -4.16 2.62 1.51

MS-08 South Central Precip. 3.83 3.65 11.37 3.84 6.98 0.63 4.39 3.76 7.34 7.35 1.46 12.54 67.14 A

2009 Depart. -2.7 -1.68 4.86 -2.04 1.36 -3.99 -0.87 -0.73 3.26 3.83 -3.5 6.87 4.67

MS-09 Southeast Precip. 3.73 3.08 10.74 5.12 9.88 1.49 3.4 3.82 7.89 5.09 2.49 14.5 71.23 A

2009 Depart. -2.66 -1.92 4.18 -0.26 4.98 -2.57 -2.02 -0.06 3.82 1.81 -2.52 9.36 12.14

MS-10 Coastal Precip. 1.84 3.23 10.89 2 4.19 1.32 5.64 5.66 6.39 6.59 2.89 16.62 67.26 A

2009 Depart. -4.49 -2.32 4.37 -3.14 -1.55 -3.62 -1.22 -0.03 0.68 3.41 -2.15 11.64 1.58
15

Table 8 - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2010 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta Precip. 6.33 3.49 2.31 3.68 5.49 1.61 2.6 2.16 1.72 2.31 6.03 1.24 38.97 A

2010 Depart. 1.39 -1.04 -3.4 -1.81 0.03 -3.36 -1.47 -0.43 -1.31 -0.94 0.55 -4.34 -16.13

MS-02 North Central Precip. 5.07 3.4 4.04 3.87 8.51 2.38 4.95 2.49 0.69 2.02 6.62 1.59 45.63 A

2010 Depart. -0.06 -1.08 -1.82 -1.58 3.01 -2.47 0.67 -0.77 -2.87 -1.43 1.28 -4.22 -11.34

MS-03 Northeast Precip. 5.44 3.45 4.2 2.5 10.42 3.08 6 2.66 1.64 2.3 5.78 2.17 49.64 A

2010 Depart. 0.16 -1.28 -2.12 -2.82 4.6 -1.44 1.75 -0.56 -2.28 -1.14 0.35 -4 -8.78

MS-04 Lower Delta Precip. 6.25 2.92 3.01 2.85 4.2 1.3 3.35 1.68 1.07 1.55 5.31 1.13 34.62 A

2010 Depart. 0.58 -1.79 -3.15 -2.82 -1.39 -3.02 -1.01 -1.03 -2 -2.15 0.01 -4.78 -22.55

MS-05 Central Precip. 5.22 3.58 4.44 3.51 6.03 3 3.98 4.44 0.56 1.92 6.11 1.58 44.37 A

2010 Depart. -0.7 -1.37 -1.88 -2.32 0.82 -0.97 -0.59 1.04 -2.89 -1.64 0.81 -4.21 -13.9

MS-06 East Central Precip. 5.86 3.61 4.56 3.49 5.91 3.21 2.81 3.58 0.82 2.4 7.24 1.09 44.58 A

2010 Depart. -0.06 -1.36 -1.7 -2.16 0.78 -1.13 -1.69 0.26 -2.79 -1 2.16 -4.25 -12.94

MS-07 Southwest Precip. 4.98 5.37 4.05 1.15 3.78 3.1 4.58 6.55 0.6 1.95 6.3 2.04 44.45 A

2010 Depart. -1.43 0.16 -2.46 -4.85 -1.66 -1.57 0.04 2.53 -3.21 -1.67 1.17 -3.97 -16.92

MS-08 South Central Precip. 4.04 5.78 3.34 2.64 5.11 3.17 6.09 8.66 0.19 1.22 5.77 1.77 47.78 A

2010 Depart. -2.49 0.45 -3.17 -3.24 -0.51 -1.45 0.83 4.17 -3.89 -2.3 0.81 -3.9 -14.69

MS-09 Southeast Precip. 4.18 6.34 4.19 3.43 5.41 3.21 3.88 6.13 0.24 1.06 4.56 1.34 43.97 A

2010 Depart. -2.21 1.34 -2.37 -1.95 0.51 -0.85 -1.54 2.25 -3.83 -2.22 -0.45 -3.8 -15.12

MS-10 Coastal Precip. 4.1 5.7 3.75 1.28 6.37 8.08 5.46 11.45 1.71 1.44 3.68 1.51 54.53 A

2010 Depart. -2.23 0.15 -2.77 -3.86 0.63 3.14 -1.4 5.76 -4 -1.74 -1.36 -3.47 -11.15
16

Table 9 - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2011 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

MS-01 Upper Delta Precip. 2.61 2.45 3.36 11.92 2.38 4.19 2.81 3.51 4.02 3.2 6.06 7.39 53.9 A

2011 Depart. -2.33 -2.08 -2.35 6.43 -3.08 -0.78 -1.26 0.92 0.99 -0.05 0.58 1.81 -1.2

MS-02 North Central Precip. 2.83 2.87 5.1 12.42 3.7 3.4 3.09 2.76 4.97 2.22 5.55 6.87 55.78 A

2011 Depart. -2.3 -1.61 -0.76 6.97 -1.8 -1.45 -1.19 -0.5 1.41 -1.23 0.21 1.06 -1.19

MS-03 Northeast Precip. 3.79 3.23 7.26 10.7 4.11 4.74 1.55 3.44 7.79 1.34 5.23 6.09 59.27 A

2011 Depart. -1.49 -1.5 0.94 5.38 -1.71 0.22 -2.7 0.22 3.87 -2.1 -0.2 -0.08 0.85

MS-04 Lower Delta Precip. 4.55 2.4 3.69 6.52 2.04 1.47 3.83 1.9 4.79 1.24 4.39 8.29 45.11 A

2011 Depart. -1.12 -2.31 -2.47 0.85 -3.55 -2.85 -0.53 -0.81 1.72 -2.46 -0.91 2.38 -12.06

MS-05 Central Precip. 5.62 2.12 6.16 6.92 1.81 2.88 7.91 1.66 9.89 1.03 3.81 6.29 56.1 A

2011 Depart. -0.3 -2.83 -0.16 1.09 -3.4 -1.09 3.34 -1.74 6.44 -2.53 -1.49 0.5 -2.17

MS-06 East Central Precip. 5.69 2.31 6.62 10.04 2.46 3.55 4.02 1.9 8.9 0.96 3.18 6.09 55.72 A

2011 Depart. -0.23 -2.66 0.36 4.39 -2.67 -0.79 -0.48 -1.42 5.29 -2.44 -1.9 0.75 -1.8

MS-07 Southwest Precip. 5.58 2.35 7.54 3.89 1.13 2.64 5.76 1.16 7.15 0.63 4.99 7.61 50.43 A

2011 Depart. -0.83 -2.86 1.03 -2.11 -4.31 -2.03 1.22 -2.86 3.34 -2.99 -0.14 1.6 -10.94

MS-08 South Central Precip. 4.21 2.97 8.85 2.57 1.05 3.81 6.56 1.75 10.44 0.4 3.54 5.17 51.32 A

2011 Depart. -2.32 -2.36 2.34 -3.31 -4.57 -0.81 1.3 -2.74 6.36 -3.12 -1.42 -0.5 -11.15

MS-09 Southeast Precip. 4.27 3.49 11.05 3.65 1.17 3.12 8.43 2.62 9.63 0.55 2.84 5.48 56.3 A

2011 Depart. -2.12 -1.51 4.49 -1.73 -3.73 -0.94 3.01 -1.26 5.56 -2.73 -2.17 0.34 -2.79

MS-10 Coastal Precip. 3.49 2.7 4.94 3.58 11.58 2.55 13.91 0.69 1.55 0.25 2.14 1.19 48.57 D

2011 Depart. -2.84 -2.85 -1.58 -4.45 -4.19 -1.36 4.72 -3.14 8.2 -2.93 -2.9 -3.79 -17.11
17

Table 10 - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2012 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

UPPER DELTA 01 Precip. 3.05 3.09 5.13 2.99 1.94 3.37 2.54 2.09 5.09 5.29 2.18 5.32 42.08 A

2012 Depart. -1.89 -1.44 -0.58 -2.5 -3.52 -1.6 -1.53 -0.5 2.06 2.04 -3.3 -0.26 -13.02

NORTH CENTRAL 02 Precip. 3.35 3.07 5.09 2.52 2.19 2.39 4.32 3.03 4.09 5.89 1.83 6.38 44.15 A

2012 Depart. -1.78 -1.41 -0.77 -2.93 -3.31 -2.46 0.04 -0.23 0.53 2.44 -3.51 0.57 -12.82

NORTHEAST 03 Precip. 5.17 4.03 6.26 2.42 2.97 2.57 5.75 3.49 5.27 4.59 1.13 7.14 50.79 A

2012 Depart. -0.11 -0.7 -0.06 -2.9 -2.85 -1.95 1.5 0.27 1.35 1.15 -4.3 0.97 -7.63

LOWER DELTA 04 Precip. 2.49 4.93 6.26 4.04 2.76 5.21 4.95 5.33 4.49 5.5 2.49 7.04 55.49 A

2012 Depart. -3.18 0.22 0.1 -1.63 -2.83 0.89 0.59 2.62 1.42 1.8 -2.81 1.13 -1.68

CENTRAL 05 Precip. 3.39 6.61 6.73 3.93 4.22 4.19 6.51 6.35 3.14 3.5 2.93 8.16 59.66 A

2012 Depart. -2.53 1.66 0.41 -1.9 -0.99 0.22 1.94 2.95 -0.31 -0.06 -2.37 2.37 1.39

EAST CENTRAL 06 Precip. 3.82 3.96 6.69 2.32 4.43 2.56 7.55 6.93 4.38 3.76 2.53 7.34 56.27 A

2012 Depart. -2.1 -1.01 0.43 -3.33 -0.7 -1.78 3.05 3.61 0.77 0.36 -2.55 2 -1.25

SOUTHWEST 07 Precip. 5.07 8.77 5.76 4.74 3.73 2.61 9.85 10.35 4.67 1.67 2.58 8.84 68.64 A

2012 Depart. -1.34 3.56 -0.75 -1.26 -1.71 -2.06 5.31 6.33 0.86 -1.95 -2.55 2.83 7.27

SOUTH CENTRAL 08 Precip. 6.51 7.64 7.69 4.36 2.09 2.42 7.7 14.15 4.09 1.66 2.76 8.56 69.63 A

2012 Depart. -0.02 2.31 1.18 -1.52 -3.53 -2.2 2.44 9.66 0.01 -1.86 -2.2 2.89 7.16

SOUTHEAST 09 Precip. 6 7.24 8.79 2.65 4.11 4.14 9.38 13.63 3.81 2.48 2.01 8.24 72.48 A

2012 Depart. -0.39 2.24 2.23 -2.73 -0.79 0.08 3.96 9.75 -0.26 -0.8 -3 3.1 13.39

COASTAL 10 Precip. 2.41 6.02 8.68 4.9 3.09 7.19 9.34 19.87 6.22 1.85 1.51 2.3 73.38 A

2012 Depart. -3.92 0.47 2.16 -0.24 -2.65 2.25 2.48 14.18 0.51 -1.33 -3.53 -2.68 7.7
18

Table 11 - CLIMATOLOGICAL DATA ANNUAL SUMMARY MISSISSIPPI 2013 TOTAL PRECIPITATION AND DEPARTURE FROM NORMAL (INCHES)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

UPPER DELTA 01 Precip. 10.23 3.78 4.68 7.77 8.99 2.17 2.58 2.71 6.7 4.92 5.48 5.25 65.26 A

2012 Depart. 5.29 -0.75 -1.03 2.28 3.53 -2.8 -1.49 0.12 3.67 1.67 0 -0.33 10.16

NORTH CENTRAL 02 Precip. 9.27 4.01 5.09 7.09 8.62 3.31 3.59 1.91 4.99 3.11 5.38 5.52 61.89 A

2012 Depart. 4.14 -0.47 -0.77 1.64 3.12 -1.54 -0.69 -1.35 1.43 -0.34 0.04 -0.29 4.92

NORTHEAST 03 Precip. 9.17 3.72 5.26 5.55 6.02 3.42 2.95 2.57 4.14 1.41 4.51 6.04 54.76 A

2012 Depart. 3.89 -1.01 -1.06 0.23 0.2 -1.1 -1.3 -0.65 0.22 -2.03 -0.92 -0.13 -3.66

LOWER DELTA 04 Precip. 10.79 5.85 4.82 6.48 5.07 3.91 2.2 1.17 5.1 7.59 5.79 4.49 63.26 A

2012 Depart. 5.12 1.14 -1.34 0.81 -0.52 -0.41 -2.16 -1.54 2.03 3.89 0.49 -1.42 6.09

CENTRAL 05 Precip. 8.8 6.91 5.41 5.78 6.12 4.3 2.63 2.33 7.27 1.91 5.92 5.12 62.5 A

2012 Depart. 2.88 1.96 -0.91 -0.05 0.91 0.33 -1.94 -1.07 3.82 -1.65 0.62 -0.67 4.23

EAST CENTRAL 06 Precip. 8.33 5.76 5.6 6.62 4.6 3.58 4.82 3.04 4.86 1.08 4.62 5.91 58.82 A

2012 Depart. 2.41 0.79 -0.66 0.97 -0.53 -0.76 0.32 -0.28 1.25 -2.32 -0.46 0.57 1.3

SOUTHWEST 07 Precip. 12.08 9.34 3.27 6.16 5.97 4.54 4.34 2.23 5.87 2.67 6.39 4.59 67.45 A

2012 Depart. 5.67 4.13 -3.24 0.16 0.53 -0.13 -0.2 -1.79 2.06 -0.95 1.26 -1.42 6.08

SOUTH CENTRAL 08 Precip. 8.36 10.1 2.56 7.01 5.29 5.04 4.94 3.84 6.28 1.39 4.85 5.78 65.44 A

2012 Depart. 1.83 4.77 -3.95 1.13 -0.33 0.42 -0.32 -0.65 2.2 -2.13 -0.11 0.11 2.97

SOUTHEAST 09 Precip. 8.33 9.72 3 6.99 6.43 6.23 5.89 4.61 4.04 2.03 5.25 6.23 68.75 A

2012 Depart. 1.94 4.72 -3.56 1.61 1.53 2.17 0.47 0.73 -0.03 -1.25 0.24 1.09 9.66

COASTAL 10 Precip. 3.8 9.99 0.79 8.57 6.73 4.49 10.42 8.32 3.01 2.25 3.39 6.48 68.24 A

2012 Depart. -2.53 4.44 -5.73 3.43 0.99 -0.45 3.56 2.63 -2.7 -0.93 -1.65 1.5 2.56
19

Table 12 - Data Completeness by Quarter

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

KGLH 0.6 0.1 0.4 0.4 0.5 1.7 2.7 0.8 0.0 4.7 1.9 0.3 0.2 8.3 2.9 1.1 0.8 1.1 0.4 0.7

KGPT 0.0 0.9 0.4 0.4 0.3 1.5 0.6 1.3 3.3 0.5 2.2 0.7 0.2 0.7 0.7 0.3 8.5 0.5 0.3 0.3

KGTR 2.2 12.3 4.0 4.8 4.7 6.4 15.4 13.2 10.4 6.7 8.1 4.9 10.2 13.1 7.4 6.0 3.2 6.7 5.0 6.3 5.4 6.1 9.9 6.7 2.7 4.2 5.2 4.3 4.4 4.7 8.5 3.0

KGWO 0.6 0.1 0.4 0.4 0.5 1.7 2.7 0.8 0.7 0.6 2.4 1.1 1.2 1.2 0.5 0.8 0.1 3.1 5.0 2.7

KHBG 0.7 0.7 0.3 0.4 0.1 1.8 0.6 0.6 1.6 1.4 2.0 2.5 0.7 0.6 0.0 0.8 0.1 1.2 0.1 2.0

KHEZ 5.3 2.0 0.3 6.9 1.6 0.6 6.0 8.8 4.1 0.6 12.0 1.2 1.5 3.1 0.1 0.8 0.0 1.1 1.0 3.6 3.2 2.8 11.5 2.7 0.1 5.9 1.5 10.0 1.3 14.6 2.8 0.3

KHKS 0.7 1.8 1.1 0.4 0.1 2.9 1.8 0.4 1.6 1.9 2.1 0.4 0.6 0.8 0.6 0.4 0.4 1.3 0.0 0.7

KJAN 0.0 0.8 0.4 0.5 0.5 1.9 0.9 0.6 0.3 1.8 0.8 0.3 0.0 0.5 0.1 0.4 0.1 1.2 0.3 0.4

KMCB 0.1 0.6 1.0 0.7 0.2 2.2 0.8 0.5 0.2 7.7 5.6 0.7 0.0 1.2 0.1 0.4 0.1 2.7 0.2 0.3

KMEI 0.1 0.3 0.3 0.3 0.1 1.2 0.1 0.4 0.1 0.9 0.6 0.4 0.0 0.3 0.1 0.3 0.1 1.1 0.1 0.4

KMEM 0.1 0.3 0.3 0.3 0.3 1.2 0.4 0.5 0.0 0.3 0.6 0.3 0.0 0.2 0.0 0.3 0.1 1.1 0.1 0.4

KMOB 0.0 0.5 0.1 0.4 0.3 2.7 0.2 0.4 1.1 0.6 1.2 0.7 0.0 0.5 0.6 0.4 0.0 0.1 0.1 0.4

KPIB 13.8 8.9 5.2 4.0 4.4 1.1 3.2 1.6 4.4 3.0 0.1 7.8 8.0 1.3 18.4 0.6 0.1 13.9 18.7 5.4 0.6 5.9 0.6 0.6 0.1 1.1 0.6 34.2

KPQL 2.7 2.0 2.5 0.6 3.9 1.4 1.5 0.5 1.1 4.0 6.2 0.6 0.1 0.6 0.8 0.6 0.1 0.1 0.5 0.3

KTUP 0.0 0.6 0.5 0.8 1.3 3.1 0.9 1.1 0.7 0.8 1.0 0.5 0.0 0.8 0.1 0.4 0.0 1.1 0.1 0.8

KTVR 0.4 1.5 5.3 1.7 1.7 2.8 0.6 1.3 0.0 2.5 2.1 0.9 0.4 0.2 1.6 0.4 0.4 4.4 9.5 4.9

KUTA 4.3 0.7 3.0 1.4 0.1 1.0 0.4 0.9 2.2 2.7 1.8 3.9 24.4 3.2 0.7 2.6 0.4 0.4 0.9 1.2 0.5 2.0 1.4 0.8

KCMB 9.2 5.9 4.4 4.8 4.5 5.9 7.8 2.8 4.8 6.1 3.9 6.3 3.2 7.5 5.1 3.2 4.7 6.4 8.2 4.5

2006 2007 2008 2009 2010 2011 2012 2013
SMEPA – R D Morrow Plant | 1–Hour SO2 NAAQS Designation Modeling Report

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APPENDIX C: RAIN CII CARBON HOURLY EMISSIONS CALCULATIONS
Parameters 2012 2013 2014

Stack	Feed	Rate1,	tph 12 12 12

SO2	Emission	rate1,	lbs/hr 241 241 330

PM	Emission	rate2,	lbs/ton 20.08 20.08 27.5

Green	Coke	Handled1,	tons/yr 38,237 35,041 36,255

Hours	of	Operation1,	hrs 5,952 5,961 6,646

Annual	Emission3,	tpy 384 352 499

Hourly	Emission	Rate4,	lbs/hr 129.02 118.06 150.06

References:

1.	Data	obtained	from	the	stack	test	report	provided	by	the	Mississippi	Department	of	Environmental	Quality

2.	PM	emission	rate	was	estimated	using	the	following	equation:

241	tph

12	lbs/hr

3.	Annual	emissions	are	estimated	using	the	following	equation:

1	ton 38237	tons 20.08	lbs 

2,000	lbs yr ton 2

4.	Hourly	Emission	Rate	was	estimated	using	the	following	equation:

2,000	lbs 384	tpy

ton 5952	hrs

Rain II Carbon Purvis Coke Plant Emission Rates for SO2 Designation Modeling

Stack	Feed	Rate,	tph

SO2	Emission	rate,	lbs/hr PM	Emission	Rate,	lbs/ton= = =20.08 lbs/ton

Annual	Emissions,	tpy= 

Hourly	Emission	Rate,	lb/hr= Annual	Emissions,	tpy Hours	of	Operation,	hrs

yr

Green	Coke	Handled,	tons PM	Emission	Rate,	lbs

ton

=

= = 129.02 lbs/hr
SMEPA – R D Morrow Plant | 1–Hour SO2 NAAQS Designation Modeling Report

Trinity Consultants

APPENDIX D: AERSURFACE OUTPUT
Jackson-A 7/30/2015

** Generated by AERSURFACE, dated 13016

** Generated from "missi.tif"

** Center Latitude (decimal degrees): 32.329111

** Center Longitude (decimal degrees): -90.182722

** Datum: NAD83

** Study radius (km) for surface roughness: 1.0

** Airport? N, Continuous snow cover? N

** Surface moisture? Average, Arid region? N

** Month/Season assignments? User-specified

** Late autumn after frost and harvest, or winter with no snow: 12,1,2

** Winter with continuous snow on the ground: 0

** Transitional spring (partial green coverage, short annuals): 3,4

** Midsummer with lush vegetation: 5,6,7,8,9

** Autumn with unharvested cropland: 10,11

FREQ_SECT MONTHLY 1

SECTOR 1 0 360

** Month Sect Alb Bo Zo

SITE_CHAR 1 1 0.17 0.81 0.337

SITE_CHAR 2 1 0.17 0.81 0.337

SITE_CHAR 3 1 0.16 0.65 0.386

SITE_CHAR 4 1 0.16 0.65 0.386

SITE_CHAR 5 1 0.16 0.63 0.405

SITE_CHAR 6 1 0.16 0.63 0.405

SITE_CHAR 7 1 0.16 0.63 0.405

SITE_CHAR 8 1 0.16 0.63 0.405

SITE_CHAR 9 1 0.16 0.63 0.405

SITE_CHAR 10 1 0.16 0.81 0.389

SITE_CHAR 11 1 0.16 0.81 0.389

SITE_CHAR 12 1 0.17 0.81 0.337

1
KHBG-New 7/29/2015

** Generated by AERSURFACE, dated 13016

** Generated from "missi.tif"

** Center Latitude (decimal degrees): 31.269483

** Center Longitude (decimal degrees): -89.256108

** Datum: NAD83

** Study radius (km) for surface roughness: 1.0

** Airport? Y, Continuous snow cover? N

** Surface moisture? Average, Arid region? N

** Month/Season assignments? User-specified

** Late autumn after frost and harvest, or winter with no snow: 12,1,2

** Winter with continuous snow on the ground: 0

** Transitional spring (partial green coverage, short annuals): 3,4

** Midsummer with lush vegetation: 5,6,7,8,9

** Autumn with unharvested cropland: 10,11

FREQ_SECT MONTHLY 1

SECTOR 1 0 360

** Month Sect Alb Bo Zo

SITE_CHAR 1 1 0.15 0.63 0.037

SITE_CHAR 2 1 0.15 0.63 0.037

SITE_CHAR 3 1 0.14 0.48 0.051

SITE_CHAR 4 1 0.14 0.48 0.051

SITE_CHAR 5 1 0.15 0.34 0.068

SITE_CHAR 6 1 0.15 0.34 0.068

SITE_CHAR 7 1 0.15 0.34 0.068

SITE_CHAR 8 1 0.15 0.34 0.068

SITE_CHAR 9 1 0.15 0.34 0.068

SITE_CHAR 10 1 0.15 0.63 0.058

SITE_CHAR 11 1 0.15 0.63 0.058

SITE_CHAR 12 1 0.15 0.63 0.037

1
Morrow_New 7/29/2015

** Generated by AERSURFACE, dated 13016

** Generated from "missi.tif"

** Center Latitude (decimal degrees): 31.218315

** Center Longitude (decimal degrees): -89.393335

** Datum: NAD83

** Study radius (km) for surface roughness: 1.0

** Airport? N, Continuous snow cover? N

** Surface moisture? Average, Arid region? N

** Month/Season assignments? User-specified

** Late autumn after frost and harvest, or winter with no snow: 12,1,2

** Winter with continuous snow on the ground: 0

** Transitional spring (partial green coverage, short annuals): 3,4

** Midsummer with lush vegetation: 5,6,7,8,9

** Autumn with unharvested cropland: 10,11

FREQ_SECT MONTHLY 1

SECTOR 1 0 360

** Month Sect Alb Bo Zo

SITE_CHAR 1 1 0.14 0.79 0.309

SITE_CHAR 2 1 0.14 0.79 0.309

SITE_CHAR 3 1 0.14 0.60 0.370

SITE_CHAR 4 1 0.14 0.60 0.370

SITE_CHAR 5 1 0.15 0.34 0.460

SITE_CHAR 6 1 0.15 0.34 0.460

SITE_CHAR 7 1 0.15 0.34 0.460

SITE_CHAR 8 1 0.15 0.34 0.460

SITE_CHAR 9 1 0.15 0.34 0.460

SITE_CHAR 10 1 0.15 0.79 0.455

SITE_CHAR 11 1 0.15 0.79 0.455

SITE_CHAR 12 1 0.14 0.79 0.309

1
SMEPA – R D Morrow Plant | 1–Hour SO2 NAAQS Designation Modeling Report

Trinity Consultants

APPENDIX E: SO2 MONITOR VALUES REPORT
Page 1 of 2

Generated: July 30, 2015

Source: U.S. EPA AirData <http://www.epa.gov/airdata>

This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level

summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based.

Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative

of the air quality for an entire county or urban area.

AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However,

some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and

tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems.

<http://www.epa.gov/airquality/airdata/ad_contacts.html>

Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon

Monitor Values Report

Geographic Area: Hinds County, MS

Pollutant: SO2

Year: 2014

Exceptional Events: Included (if any)

Page 1 of 2

Generated: July 30, 2015

Source: U.S. EPA AirData <http://www.epa.gov/airdata>

This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level

summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based.

Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative

of the air quality for an entire county or urban area.

AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However,

some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and

tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems.

<http://www.epa.gov/airquality/airdata/ad_contacts.html>

Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon

Monitor Values Report

Geographic Area: Hinds County, MS

Pollutant: SO2

Year: 2014

Exceptional Events: Included (if any)

Duration Description=1 HOUR

Duration

Description Obs

First

Max

Second

Max

99th

Percentile

Actual

Exc

Exc

Events

Monitor

Number Site ID Address City County State

EPA

Region

1 HOUR 8161 39 18 14 0 None 1 280490020 232 East Woodrow Wilson Drive Jackson Hinds MS 04
Page 2 of 2

Generated: July 30, 2015

Source: U.S. EPA AirData <http://www.epa.gov/airdata>

This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level

summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based.

Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative

of the air quality for an entire county or urban area.

AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However,

some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and

tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems.

<http://www.epa.gov/airquality/airdata/ad_contacts.html>

Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon

Monitor Values Report

Geographic Area: Hinds County, MS

Pollutant: SO2

Year: 2014

Exceptional Events: Included (if any)

Page 2 of 2

Generated: July 30, 2015

Source: U.S. EPA AirData <http://www.epa.gov/airdata>

This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level

summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based.

Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative

of the air quality for an entire county or urban area.

AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However,

some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and

tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems.

<http://www.epa.gov/airquality/airdata/ad_contacts.html>

Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon

Monitor Values Report

Geographic Area: Hinds County, MS

Pollutant: SO2

Year: 2014

Exceptional Events: Included (if any)

Duration Description=24-HR BLK AVG

Duration

Description Obs

First

Max

Second

Max

99th

Percentile

Actual

Exc

Exc

Events

Monitor

Number Site ID Address City County State

EPA

Region

24-HR BLK AVG 355 4 3 3 0 None 1 280490020 232 East Woodrow Wilson Drive Jackson Hinds MS 04