====== 3. AERMET ======


With the output data from [[aersurface|AERSURFACE]], we can begin running **AERMET**.

===== 3.1. Introduction =====

**AERMET** is a meteorological preprocessor used with the [[aermod|AERMOD]] air dispersion model. Its main function is to process surface and upper-air meteorological data to generate the necessary input files for [[aermod|AERMOD]] simulations. **AERMET** calculates key atmospheric parameters such as wind profiles, atmospheric stability, temperature gradients, and turbulence characteristics. These parameters are essential for accurately modeling how pollutants disperse in the atmosphere.

^ Aspect ^ Details ^
| Objective | Preprocess meteorological data for [[aermod|AERMOD]], generating atmospheric profiles and planetary boundary layer (PBL) parameters. |
| Inputs | Surface data, upper-air sounding (radiosonde), and site characteristics (Surface roughness length (**Zo**), Albedo (**Alb**), and Bowen ratio (**Bo**)). |
| Outputs | • ''.SFC file'' - Processed surface data (10m wind, temperature, turbulence parameters) \ • ''.PFL file'' - Vertical atmospheric profiles (wind/temperature aloft, PBL height) |

===== 3.2. Required Files for AERMET =====

==== 3.2.1. AERMET Executable ====
First, download the executable from the [[https://www.epa.gov/scram/meteorological-processors-and-accessory-programs|EPA AERMET]] website.

Navigate to the **MODEL CODE** section and click the executable compatible with your operating system version, as shown in [[#Figure 1|Figure 1]]. Extract the downloaded file to the folder:
''C:\Users\Cliente\Desktop\AermodTutorial\3.AERMET''.

== Figure 1 ==
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{{:aermetepa.png |Figure 1 – AERMET download}}
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Figure 1: Download the AERMET executable according to its specifications.
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==== 3.2.2. Surface Data ====
To download surface data, access the [[https://www.ncei.noaa.gov/pub/data/noaa/|NOAA surface data]] website and navigate to the directory for the year 2024, as shown in [[#Figure 2|Figure 2]]:

== Figure 2 ==
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{{:surface2024.png |Figure 2 – Surface data download}}
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Figure 2: Click on the year 2024.
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Now search for the file named ''724397-54831-2024.gz'' (for the ''Central Illinois Regional Airport station''), download it, and extract it to the folder:
''C:\Users\Cliente\Desktop\AermodTutorial\3.AERMET''.
Finally, rename the file to ''724397-54831-2024.dat'', create a subfolder named ''Surface_data'', and move the file there, as shown in [[#Figure 3|Figure 3]]:

== Figure 3 ==
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{{:surfacepasta.png |Figure 3 – Surface data}}
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Figure 3: Organized raw surface data file.
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==== 3.2.3. Upper Air Data ====
Lastly, download the radiosonde data from the [[https://www.ncei.noaa.gov/data/integrated-global-radiosonde-archive/access/data-por/|radiosonde archive]], searching for the station ''USM00074560-data'' (for ''Lincoln, IL'', the closest radiosonde station to Bloomington).
Download the file as shown in [[#Figure 4|Figure 4]], and extract it to:
''C:\Users\Cliente\Desktop\AermodTutorial\3.AERMET''.

== Figure 4 ==
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{{:USM.png |Figure 4 – Radiosonde data download}}
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Figure 4: Download the file ''USM00074560-data-beg2021.txt.zip''.
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Rename the file to ''USM'', create a new subfolder named ''Upper_Air_data'', and move the file there (''C:\Users\Cliente\Desktop\AermodTutorial\3.AERMET\Upper_Air_data''), as shown in [[#Figure 5|Figure 5]]:

== Figure 5 ==
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{{:figura5.png |Figure 5 – Organized radiosonde data}}
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Figure 5: Rename the file and move it to the new folder.
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===== 3.3. Configuring AERMET =====
Now that all required input data is ready, we will split the processing into two stages:

  * Stage 1: Extracts surface and upper-air data from archived formats and performs quality control.
  * Stage 2: Processes Stage 1 outputs to calculate boundary layer parameters for [[aermod|AERMOD]].

The workflow is illustrated in [[#Figure 6|Figure 6]]:

== Figure 6 ==
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{{:AERMETSTG.png |Figure 6 – AERMET workflow}}
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Figure 6: AERMET processing stages.
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==== 3.3.1. AERMET STAGE 1 ====
Create a text file named ''aermet_STG1.txt'' in ''C:\Users\Cliente\Desktop\AermodTutorial\3.AERMET'' with the following content:

<code> ** Stage 1 job messages msgSTG1.mes report msgSTG1.rpt
upperair
** Upper air data for Bloomington, IL
data .\Upper_Air_data\USM.txt IGRA
extract upper.iqa
location 00074560 40.15N 89.33W 5 179.2
xdates 2024/1/1 to 2024/1/2
qaout upper.oqa

surface
** Surface data for Central IL, Bloomington/Normal
data .\Surface_data\724397-54831-2024.dat ISHD
extract surface.iqa
qaout surface.oqa
location 54831 40.66N 89.69W 5
xdates 2024/1/1 to 2024/1/2
</code>

=== 3.3.1.1. Stage 1 AERMET Configuration ===
== JOB Section ==
| Line | Description |
| messages m1.mes | Log file storing processing messages |
| report m1.rpt | Detailed report file with processing results |

== UPPERAIR Section ==
| Line | Description |
| data .\Upper_Air_data\USM.txt IGRA | Path to raw radiosonde data in IGRA format |
| extract upper.iqa | Output file with extracted data (pre-QA) |
| location 00074560 40.15N 89.33W 5 179.2 | Station details: \ • Code: 00074560 \ • Coordinates: 40.15N 89.33W \ • Anemometer height: 5m \ • Terrain elevation: 179.2m |
| xdates 2024/1/1 to 2024/12/31 | Processing period (full year) |
| qaout upper.oqa | Final post-QA output file |

== SURFACE Section ==
| Line | Description |
| data .\Surface_data\724397-54831-2024.dat ISHD | Surface data in ISHD format (Integrated Surface Hourly Data) |
| extract surface.iqa | Extracted data before QA |
| qaout surface.oqa | Validated data ready for use |
| location 54831 40.66N 89.69W 5 | Station details: \ • WBAN code: 54831 \ • Coordinates: 40.66N 89.69W \ • Measurement height: 5m |
| xdates 2024/1/1 to 2024/12/31 | Time window matching upper-air data |

==== 3.3.2. AERMET STAGE 2 ====
Create another text file named ''aermet_STG2.txt'' in the same folder with:

<code> ** Stage 2 JOB MESSAGES mcr_st2.mes REPORT mcr_st2.rpt
UPPERAIR
QAOUT upper.oqa

SURFACE
QAOUT surface.oqa

METPREP
OUTPUT METAR.SFC
PROFILE METAR.PFL
LOCATION 000001 40.47N 88.97W 0
METHOD REFLEVEL SUBNWS
METHOD WIND_DIR RANDOM
NWS_HGT WIND 6.1
AERSURF BL_2024_Imp_Can.sfc
</code>

=== 3.3.2.1. Stage 2 AERMET Configuration ===
== METPREP Section ==
| Line | Description |
| OUTPUT METAR.SFC | Processed surface data output file |
| PROFILE METAR.PFL | Processed vertical profiles output file |
| LOCATION 000001 40.47N 88.97W 0 | Site details: \ • Code: 000001 \ • Coordinates: 40.47N 88.97W \ • Reference height: 0m |
| METHOD REFLEVEL SUBNWS | Reference height method (NWS standard) |
| METHOD WIND_DIR RANDOM | Wind direction handling for missing data (random imputation) |
| NWS_HGT WIND 6.1 | NWS standard wind measurement height (6.1m) |
| AERSURF BL_2024_Imp_Can.sfc | Surface characteristics file from [[aersurface|AERSURFACE]] |

===== 3.4 Running AERMET =====
Open Command Prompt and run:

  - Navigate to the folder: ''cd C:\Users\Cliente\Desktop\AermodTutorial\3.AERMET''
  - Execute Stage 1: ''aermet aermet_STG1.txt'' ([[#Figure 8|Figure 8]])
  - Execute Stage 2: ''aermet aermet_STG2.txt'' ([[#Figure 9|Figure 9]])

== Figure 8 ==
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{{:stg1CMD.png |Figure 8 – Running Stage 1}}
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Figure 8: Executing Stage 1.
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== Figure 9 ==
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{{:stg2CMD.png |Figure 9 – Running Stage 2}}
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Figure 9: Executing Stage 2.
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===== What is next? =====

With this completed, we can proceed to [[aermap|AERMAP]],  which is the last processor before moving on to [[aermod|AERMOD]].

Attachment
Here you can download the folder I used to create this document. It is important that you use it only for comparison purposes or in case you are unable to make progress on the project. Attached: {{ :3.aermet.rar | aermet.rar}}