1. AERMET – Part 2 Course #423 Day 2 Morning
Air Pollution Dispersion Models:
Applications with the AERMOD Modeling System
AERMET – Part 2
Course #423
Day 2 Morning

2. Day 2 Morning: AERMET – Part 2

3. Overview This lesson introduces: AERMET Pathways and Keywords
AERMET Processing Stages
Special Topics in AERMET
Running AERMET
Evaluating AERMET Output

4. Learning Objectives At the end of this training, you will be able to:
Understand the pathways, keywords, and options in AERMET control files
How to construct a control file
How to run AERMET and its multiple stages
How to understand and QA AERMET output

5. AERMET Processing
AERMET processes meteorological data in three steps, or stages:
Stage 1 extracts data from an archive format and performs a basic QA.
Stage 2 combines data from Stage1 into 1-day blocks. Stage 2 also provides means of incorporating the hourly-averaged 1-minute ASOS data.
Stage 3 develops the ‘surface file’ and ‘profile file’ that are the meteorological input files to AERMOD.

6. The Control File What is a Control File?
A text file that informs AERMET how to process the data for each processing stage
AERMET processes data in three stages
Stage 1 – extract and QA data
Stage 2 – merge data into 1-day blocks
Stage 3 – make calculations and output files for AERMOD
Each control file contains multiple records
Two or more pathways
JOB pathway always required
Keywords associated with the pathway
Parameters associated with the keywords
At least one blank space between each field
Stage = processing step; review the stages from Day 1:
Stage 1: Extracts surface and upper air data from “archive” format and performs basic QA. Performs QA only on on-site data.
Stage 2: Combines QA’d data into 1-day ‘chunks’. Not really meant for review but can help troubleshooting problems.
Stage 3: Develops the files needed by AERMOD
“Surface” file: Boundary layer parameters.
“Profile” file: One or more levels of wind data.
Most keywords require one or more parameters, although there are a few exceptions.
Each record in the control file can be no longer than 132 characters, including spaces.

7. The Control File What is a PATHWAY?
A single ‘term’ that identifies an AERMET function
AERMET Pathways
JOB – report files (all stages)
SURFACE – typically NWS hourly observations (stage 1)
UPPERAIR – typically twice-daily NWS soundings (stage 1)
ONSITE – site-specific data (stage 1)
MERGE – stage 2
METPREP – stage 3
Recall: Pathways were identified on Day 1
JOB Pathway
Used to identify two report files: MESSAGE, which is a compilation of all messages issued by AERMET processing and REPORT, which is a summary of the messages.
Also has a third keyword: CHK_SYNTAX, which checks the syntax of each record without running AERMET.
SURFACE Pathway
Used to specify NWS hourly weather observations, including the latitude, longitude and time zone. Time zones are the usual zones relative to Greenwich.
NOTE 1: Specifying the time zone adjustment is opposite of our usual thinking. Zones WEST of Greenwich are specified in AERMET as POSITIVE values; zones east of Greenwich are specified as negative. This ‘reversal’ is because MPRM and AERMET were originally developed with North America in mind (west of Greenwich) and therefore there was no need to specify a sign. The global use of AERMET was not foreseen when it was developed.
NOTE 2: ISHD format is the only format currently processed by AERMET that records time as GMT; all others are in local standard time (and never reported in daylight time).

8. The Control File What is a KEYWORD?
An identifier that tells AERMET what data to process, information about the data, or how to process the data
Each pathway has unique keywords as well as some that are common to several pathways, especially in stage 1
Next – a look at each stage and the allowable pathways and keywords
In the slides that follow, a parameter with square brackets around it, for example [tadjust], is optional and need not be specified
Keywords,their definitions and usage will be discussed in subsequent slides.

9. The Control File
STAGE 1
Extracts data from an archive file (SURFACE, UPPERAIR)
Archive file – a fixed and unchanging format for storing data
Allowable pathways
JOB
SURFACE
UPPERAIR
ONSITE
Performs a basic check on the quality of the data (SURFACE, UPPERAIR, ONSITE)
Remember, Stage 1 extracts surface and upper air data from “archive” format and performs basic QA on the surface, upper air, and onsite data.
The allowable pathways include JOB, SURFACE, UPPERAIR, and ONSITE.
The data QA procedures include checks for missing data and valid range checks on most parameters (e.g., wind speed, wind direction, and temperature) to ensure the data fall within a valid range of values, and data consistency checks between parameters that are related.

10. The Control File - JOB JOB pathway and keywords
Allows the user to specify the files where all messages are stored and summarized
MESSAGES: Name of the file where AERMET will store all the messages during the run
MESSAGES message_filename
REPORT: Name of the file where AERMET generates a summary of the input and the messages
REPORT summary_filename
CHK_SYNTAX: Optional keyword that tells AERMET to check the syntax of the control file, but not process any data
CHK_SYNTAX
JOB Pathway
MESSAGE: mandatory, non-repeatable
message_filename
Use standard Windows file naming procedures.
REPORT: optional, non-repeatable (if the keyword is present)
summary_filename
Use standard Windows file naming procedures; the results written to the monitor if this keyword is omitted.
CHK_SYNTAX: optional, non-repeatable (if the keyword is present)
With the speed of today’s computers, this keyword is likely little used and should probably be considered obsolescent since AERMET will not run with an error in the control file.

11. The Control File - JOB Example: JOB REPORT EXAMPLE.RPT
MESSAGES EXAMPLE.MSG
Unless a file path is specified with the filename, the files are created in the same folder as the control file.
A note on indenting:
Indenting the keyword records makes reading the control files a little easier.
Unlike AERMOD and AERMAP, there is no set column or character position in which pathways and keywords must start.

12. The Control File - SURFACE
SURFACE pathway and keywords
The section that tells AERMET what hourly NWS weather observations to process
DATA: Input filename of the ‘archived’ data
DATA archive_filename file_format [ASOS]
EXTRACT: Output filename of extracted data
EXTRACT extracted_data_filename
QAOUT: Output filename of extracted data after it has undergone quality assurance procedures
QAOUT qa_output_filename
SURFACE Pathway
DATA: Mandatory, non-repeatable
archive_filename: The name of the file in which the ‘raw’ data are located in one of the valid formats.
file_format: One of the valid formats that AERMET can process.
CD144: Old ‘card’ format.
SCRAM: A reduced form of the CD144 data that used to be available on the EPA BBS and web site.
SAMSON: Data retrieved from one of the SAMSON compact discs:
Solar and Meteorological Surface Observation Network ( )
HUSWO: Data retrieved from one of the HUSWO compact discs:
Hourly United States Weather Observations ( )
Assumes data extracted in METRIC units.
3280VB or 3280FB: A format designed for magnetic tape; not is use, but there may be files ‘around’ that were used in much earlier AERMET applications; VB = variable block length; FB = fixed block length.
ISHD : Data obtained from CD or online (TD-3505) – the current format supported by National Climatic Data Center (NCDC).
NOTE: an abbreviated form of the data are available online from NCDC as well as the full format – AERMET cannot process the abbreviated format.
[ASOS]: An optional parameter associated ONLY with ISHD data to indicate the data are from and ASOS station.
Instructs AERMET to apply the wind speed truncation adjustment to all hours .
Beginning with version 11059, AERMET includes a table of ASOS commission dates, which is used to identify whether surface data input to AERMET are from an ASOS site.
NOTE: used only if the data are known to be from an ASOS site which is not included in the ASOS station list within AERMET.

13. The Control File - SURFACE
SURFACE (cont’d)
ASOS1MIN: The file with the hourly-averaged 1-minute ASOS data to be merged in Stage 2
ASOS1MIN asos1min_filename
LOCATION: Identifies the station and its location
LOCATION site_id lat/lon lon/lat [tadjust] [elevation]
XDATES: Specifies the date range to extract from the ‘archive’
XDATES YB/MB/DB [TO] YE/ME/DE
SURFACE Pathway (cont’d)
ASOS1MIN – optional, non-repeatable
THIS KEYWORD IS MEANT FOR USE WHEN MERGING DATA ONLY – IF IT IS INCLUDED IN THE STAGE 1 PROCESS, IT IS IGNORED.
asos1min_filename: Output from AERMINUTE and is NOT the actual 1-minute data available on the NCDC web site.
LOCATION – mandatory, non-repeatable
site_id: Identifies the site/station in the archive file to extract (retrieve).
In the days of magnetic tapes, it was not uncommon for multiple sites to exist on one tape; generally now there is only one site per file.
lat/lon: The latitude (or longitude) in decimal degrees with the suffix N for stations north of the equator, S for sites south of the equator (or W for stations west of Greenwich, E for station east of Greenwich).
You can specify the latitude first or longitude first; AERMET figures it out based on the suffix. Be sure to specify both a latitude and longitude.

14. The Control File - SURFACE
SURFACE (cont’d) – the following keywords relate to the QA
AUDIT: Identifies the variables to QA beyond the three default variables
AUDIT sfname1 … sfnameN
RANGE: Set new upper, lower bounds for the QA and missing indicator
RANGE sfname lower_bound <[=] upper_bound missing_indicator
NO_MISSING: Suppresses missing data QA messages to the MESSAGE file and does not tally the number missing for the QA’d variables
NO_MISSING sfname1 sfname2 … sfnameN
SURFACE Pathway (cont’d)
AUDIT: Optional, repeatable
sfname: Internal 4-character AERMET names of NWS variables as defined in Table B-2 of the Appendix in the AERMET User’s Manual.
Each variable has a default set of values for these parameters – see Table B-2.
Default variables: temperature (TMPD), wind speed (WSPD), wind direction (WDIR) (AERMET names are in parentheses).
RANGE: Optional, repeatable
sfname: Internal AERMET names (see AUDIT).
lower_bound: Specify the (new) lower bound for sfname.
<[=]: Symbol indicating lower_bound less than upper_bound and optionally [=] to include the endpoints.
upper_bound: Specify the (new) upper bound for sfname.

15. The Control File - SURFACE
An example for the SURFACE pathway:
SURFACE
DATA dat ISHD
EXTRACT SFEXOUT.dat
QAOUT SFQAOUT.dat
LOCATION N W
XDATES 96/12/01 96/12/31
AUDIT DPTP PRES
RANGE TMPD -100 <
RANGE DPTP -200 <
Raleigh-Durham, NC
The first 3 keyword entries are straightforward, with the archive data in the ISHD (Integrated Surface Hourly Data) format
The first field after the LOCATION specifies the site identifier; the ID is a World Meteorological Organization (WMO) classification. For North America, these usually start with 72 for the U.S. and 71 for Canada (there are exceptions). Another, and possibly more common, classification is the Army-Navy Weather Bureau (WBAN) scheme; a list of WBAN number can be found on the NCDC web site.
The site ID for Houston, TX airport, which is at North latitude and West longitude
As noted earlier, the latitude and longitude could be reversed (95.350W N) and AERMET would interpret it correctly. Note that there is no blank between the value and the N and W
Houston is 6 times zones west of Greenwich so a ‘6’ is entered for the time adjustment since ISHD data is reported as GMT. If the data format had been, for example SAMSON, the value could have been omitted or a 0 (zero) entered (the years would have been different since SAMSON ended in 1990)
The station is 29.0 meters above mean sea level
The period of interest is December 1, 1996 through December 31, 1996.

16. The Control File - UPPERAIR
UPPERAIR pathway and keywords
The section that tells AERMET what upper air soundings to process
DATA: Input filename of the ‘archived’ data
DATA archive_filename file_format
EXTRACT: Output filename of extracted data
EXTRACT extracted_data_filename
QAOUT: Output filename of extracted data after it has undergone quality assurance procedures
QAOUT qa_output_filename
UPPERAIR Pathway
DATA: Mandatory, non-repeatable
archive_filename: The name of the file in which the ‘raw’ data are located in one of the valid formats.
file_format: One of the valid formats that AERMET can process.
EXTRACT: Mandatory, non-repeatable
extracted_data_filename: The name of the file where data are stored as they are extracted from the DATA archive_filename.
QAOUT: Mandatory, non-repeatable (mandatory only if you want to QA the data)
qa_output_filename: The name of the file where data are stored as each record is quality assured.
Performs simple comparisons to upper and lower bounds on a record-by-record (hour-by- hour) basis; temporal variations are not checked, for example, large hour-to-hour variations would not be caught.
AERMET will only report a potential issue and WILL NOT modify the data; it is up to the user to review the QA messages and modify the data (with sufficient justification).
Shortly we will see how to adjust AERMET’s internal QA limits.
Performing the QA is optional – AERMET can process extracted-only data in stage 2.

17. The Control File - UPPERAIR
UPPERAIR (cont’d)
LOCATION: Identifies the station and its location
LOCATION site_id lat/lon lon/lat tadjust
XDATES: Specifies the date range to extract from the ‘archive’
XDATES YB/MB/DB [TO] YE/ME/DE
MODIFY: A flag indicating to ‘correct’ a sounding for specific conditions
UPPERAIR (cont’d)
LOCATION: Mandatory, non-repeatable
site_id: Identifies the site/station in the archive file to extract (retrieve).
In the days of magnetic tapes, it was not uncommon for multiple sites to exist on one tape; generally now there is only one site per file.
lat/lon: Specify the latitude (or longitude) in decimal degrees with the suffix N for stations north of the equator, S for sites south of the equator (or W for stations west of Greenwich, E for station east of Greenwich).
You can specify the latitude first or longitude first; AERMET figures it out based on the suffix.
lon/lat: Specify the longitude (or latitude) in decimal degrees with suffix W for stations west of Greenwich, E for station east of Greenwich (or suffix N for stations north of the equator, S for sites south of the equator).
Be sure to specify both a latitude and longitude.
tadjust: Time zone relative to Greenwich Mean Time in order to adjust the reported time to LOCAL STANDARD time.
Upper air soundings are always reported in GMT so this adjustment must be present and, except for soundings in the same zone as Greenwich, will not be zero (0).
It’s important to understand the ‘reverse’ nature longitude and time zone in AERMET .

18. The Control File - UPPERAIR
UPPERAIR (cont’d) – the following keywords relate to the QA
AUDIT: Identifies the variables to QA beyond the three default variables
AUDIT uaname1 … uanameN
RANGE: Set new upper, lower bounds for the QA and missing indicator
RANGE uaname lower bound <[=] upper_bound missing_indicator
NO_MISSING: Suppresses missing data QA messages to the MESSAGE file and does not tally the number missing for the QA’d variables
NO_MISSING uaname1 uaname2 … uanameN
UPPERAIR (cont’d)
AUDIT – optional, repeatable
uaname: Internal 4-character AERMET names of upper air variables as defined in Table B-1 of the Appendix in the AERMET User’s Manual.
Each variable has a default set of values for these parameters – see Table B-1.
Default variables: none.
RANGE – optional, repeatable
uaname: Internal AERMET names (see AUDIT).
lower_bound: Specify the (new) lower bound for sfname.
<[=]: Symbol indicating lower_bound less than upper_bound and optionally [=] to include the endpoints.
upper_bound: Specify the (new) upper bound for sfname.

19. The Control File - UPPERAIR
An example for the UPPERAIR pathway:
UPPERAIR
DATA FSL FSL
EXTRACT UAEXOUT.DAT
QAOUT UAQAOUT.DAT
XDATES 96/12/01 TO 96/12/31
LOCATION N W
AUDIT UAPR UAHT UATT
RANGE UAHT 0 <=
RANGE UAPR <
The first 3 keyword entries are straightforward, with the archive data in the FSL (Forecast Systems Laboratory) format
The first field after the LOCATION specifies the site identifier; an Army-Navy Weather Bureau (WBAN) number is used in this file; a list of WBAN number can be found on the NCDC web site
The site ID for Lake Charles, LA, which is at North latitude and West longitude
As noted earlier, the latitude and longitude could be reversed (78.786W N) and AERMET would interpret it correctly
Lake Charles is 6 times zones west of Greenwich so a ‘6’ is entered for the time adjustment
The elevation is 4.6 meters above mean sea level
The period of interest is December 1, 1996 through December 31, 1996
For the UPPERAIR pathway, there are no variables that are QA’d by default in AERMET

20. The Control File - ONSITE
ONSITE pathway and keywords
The section instructs AERMET how to process site-specific data
For a regulatory application, site-specific data must comply with approved plans for data collection and meet 90% completeness criteria (per quarter and annually) and includes periodic calibration and performance testing of the instrumentation.
ONSITE Pathway
Stress the importance of having quality site-specific data.
If you have 90% completeness for 4 consecutive quarters, you automatically have 90% annual completeness.
The reverse is not true: 90% annual completeness does not imply 4 consecutive quarters of 90% completeness.
For example, 3 quarters of 100% completeness and 1 quarter of 88% completeness results in > 90% completeness, but does not meet the completeness criterion.

21. The Control File - ONSITE
ONSITE (cont’d)
Recall that site-specific data are not in a data archive, so there is no EXTRACT keyword
DATA: Input filename of the data to process
DATA filename
QAOUT: Output filename of extracted data after it has undergone quality assurance procedures
QAOUT qa_output_filename
ONSITE (cont’d)
DATA: Mandatory, non-repeatable
filename: The name of the file in which the ‘raw’ data are located.
file_format: There is no predetermined format – we see below how to instruct AERMET on how to read the data.
QAOUT: Mandatory, non-repeatable
qa_output_filename: The name of the file where data are stored as each record is quality assured.
Performs simple comparisons to upper and lower bounds on a record-by-record (hour-by-hour) basis; temporal variations are not checked, for example, large hour-to- hour variations would not be caught.
AERMET will only report a potential issue and WILL NOT modify the data; it is up to the user to review the QA messages and modify the data (with sufficient justification).
Performing the QA is mandatory – primarily to get the ‘format’.

22. The Control File - ONSITE
ONSITE (cont’d)
LOCATION: Identifies the station and its location
LOCATION site_id lat/lon lon/lat [tadjust]
XDATES: Specifies the date range to extract from the ‘archive’
XDATES YB/MB/DB [TO] YE/ME/DE
THRESHOLD: Sets the minimum wind speed (meters/second) below which the wind is treated as calm
THRESHOLD threshold_wind_speed
ONSITE (cont’d)
LOCATION: Mandatory, non-repeatable
site_id: Normally there is no site ID associated with site-specific data – any 5-digit number can be used here (do NOT use alphabetic characters).
lat/lon: Specify the latitude (or longitude) in decimal degrees with the suffix N for stations north of the equator, S for sites south of the equator (or W for stations west of Greenwich, E for station east of Greenwich).
You can specify the latitude first or longitude first; AERMET figures it out based on the suffix.
lon/lat: Specify the longitude (or latitude) in decimal degrees with suffix W for stations west of Greenwich, E for station east of Greenwich (or suffix N for stations north of the equator, S for sites south of the equator).
Be sure to specify both a latitude and longitude.
[tadjust]: Time zone relative to Greenwich Mean Time in order to adjust the reported time to LOCAL STANDARD time.
Site-specific data are almost always reported in local time; one exception could be the data are reported in daylight savings time, in which case a 1-hour adjustment is required

23. The Control File - ONSITE
ONSITE (cont’d)
READ: Specifies the list and order of variables in the site-specific data file that are to be read
Divided into vector and scalar quantities
Vector – observations from one or more levels
‘nn’ at the end of each name represent the level of the observation (not the height)
Height (HTnn)
Vertical wind component (VVnn)
Dry bulb temperature (TTnn)
Std. deviation of horizontal wind direction (SAnn)
Wind speed (WSnn)
Std. deviation of vertical wind (SEnn)
Wind direction (WDnn)
Std. deviation of u-comp. of wind (SUnn)
Dew point temperature (DPnn)
Std. deviation of v-comp. of wind (SVnn)
Relative humidity (RHnn)
Std. deviation of w-comp. of wind (SWnn)
ONSITE (cont’d)
This and the defining the layout of the data are the most difficult part of AERMET.
The value of ‘nn’ should start at 01.
The maximum number of levels is 50; while this seems like a large number of levels, it is for a tower, but AERMET is not limited to tower data; for example, sodar data can be used as well.

24. The Control File - ONSITE
ONSITE (cont’d)
Scalar – observations at a single height plus date and time
Specifying the variables with the READ record
READ record_index osname1 … osnameN
Year (OSYR)
Mixing height (MHGT)
Month (OSMO)
Surface roughness length (ZOHT)
Day (OSDY
Solar radiation (INSO)
Hour (OSHR)
Net radiation (NRAD)
Minute (OSMN)
Temperature difference (DT01)
Sensible heat flux (HFLX)
Precipitation amount (PAMT)
Surface friction velocity (USTR)
Plus several others
ONSITE (cont’d)
The most important onsite parameters include :
date and time
net radiation
solar radiation
temperature difference.
The latter two are collected in areas where the NWS data are sparse such as the North Slope of Alaska;.
A note on DT01: There are actually three DT01, DT02, and DT03 but only DT01 is in use at the current time (also it is DT zero-one).
The solar radiation/deltaT (INSO/DTnn) method is used to calculate stability in the absence of NWS cloud cover (it can be used even if cloud cover is available but is the only current option when cloud cover is not available).
Assumes DTnn is (higher level – lower level).
Only DT01 is in use in AERMET; the other two (DT02 and DT03) are in reserve if they are needed for future enhancements.
It is rare to see variables such as mixing height, heat flux, and friction velocity used except for a scientific field experiment.
READ: Mandatory, repeatable
record_index: Links the list of names on the READ keyword to the corresponding FORMAT keyword.
osname: One of the valid variable names.
The date and time information must be on the first record, followed by the actual data either on the same record (if there are only a few variables) or on subsequent READ records (remember this keyword is repeatable).
Remember that the maximum record length is 132 characters.
This could be a problem if all the data are on one record and defining the structure (through the READ keywords) would require more than 132 characters.

25. The Control File - ONSITE
ONSITE (cont’d)
FORMAT: The format of the data using FORTRAN formatting rules
Date and time fields are integer values
All others are real values
The format used to read the data is also used to write it out
Specifying the format
FORMAT record_index Fortran_format
Fortran_format is a string that follows Fortran language standards
Beginning with version 11059, if there are delimeters (spaces, tabs, commas) between each field on a data record, the Fortran_format can be specified as ‘FREE’ (without quotation marks; not case-sensitive) – simplifies the input
ONSITE (cont’d)
FORMAT: Mandatory, repeatable
record_index: Links the list of names on the READ keyword to the corresponding FORMAT keyword.
fortran_format: The Fortran-like statement.
Usually the date and time information come first followed by the actual data either on the same record (if there are only a few variables) or on subsequent READ records (remember this keyword is repeatable).
Remember that the maximum record length is 132 characters.
This could be a problem if all the data are on one record and defining the structure (through the READ keywords) would require more than 132 characters.

26. The Control File - ONSITE
ONSITE (cont’d)
Specify FREE format for some data records, while specifying the Fortran FORMAT explicitly for other data records
AERMET User’s Manual gives instructions and guidance on developing the Fortran_format
Restrictions
ASCII text file
Records for one observation period must be contiguous
Same variables must appear for all observation periods
Date and time must be on first record of each observation period and are integer values
Specify variables according to the internal names on previous slides and are real values
ONSITE (cont’d)

27. The Control File - ONSITE
ONSITE (cont’d)
General layout of a Fortran_format
(field descriptors)
Parentheses required
Field Descriptors
I – integer value
F – real value, floating point
E – real value, exponential notation
X – skip
T – tab to column
For the date and time, use the I field descriptor
I is followed by the field width (# columns), e.g. I4
For all other variables, F is the most likely descriptor (we seldom see the E descriptor)
F is followed by the field width (w), a decimal point, and the number of digits after the decimal point (d), i.e. Fw.d; e.g., F7.3
ONSITE (Cont’d)

28. The Control File - ONSITE
ONSITE (cont’d)
Use the X descriptors to skip columns or T descriptor to tab to a specific column
The number of columns to skip precedes the X descriptor, e.g., 20X
The column to tab to follows the T descriptor, e.g. T40
Data are written to QAOUT file in the same format they are read into AERMET
Use a backward slash (\) to skip an entire record
ONSITE (cont’d)
If there are variables that are not a part of the list of valid variables or you just don’t want to include one in the data, use the X descriptor to skip columns or T descriptor to tab to a specific column.
Remember: whatever format you use to read the data will be used to write it back out to the QAOUT file, so if you are skipping fields, there will be blanks on output where there were data on input
If you want or need to skip entire records, a backward slash (\) can be entered – use with some caution to be sure you are skipping the right records

29. The Control File - ONSITE
Site-specific data example for ONSITE pathway:
Blank lines were added in this example for clarity; normally the blank lines would not be there
Fields 1-4: 1 March 1996, hours 1, 2 and 3 (OSDY, OSMO, OSYR, OSHR)
Field 5: Skipped (see FORMAT on next slide)
Field 6: Height (HT), meters
Field 7: Std deviation of the horizontal wind direction (SA), meters/second
Field 8: Std deviation of the vertical wind speed (SW), meters/second
Field 9: Dry bulb temperature (TT), in Celsius – watch the units here!
Field 10: Wind direction (WD), degrees
Field 11: Wind speed (WS), meters/second
Instructor Note: Take the opportunity to talk about the relationship between wind speed and σA. Lower wind speeds, higher σA and vice-versa. Low wind speeds, more back-and-forth, larger variance; high wind speed, more steady, smaller variance.

30. The Control File - ONSITE
An example for the ONSITE pathway (based on site-specific data):
(the first record on previous slide is repeated here)
ONSITE
DATA ONSITE.MET
QAOUT OSQAOUT.DAT
XDATES 96/3/1 TO 96/3/10
LOCATION W 30.3N 0
READ 1 OSDY OSMO OSYR OSHR HT01 SA01 SW01 TT01 WD01 WS01
READ HT02 SA02 SW02 TT02 WD02 WS02
READ HT03 SA03 SW03 TT03 WD03 WS03
FORMAT 1 (4(I2,1X),4X,F5.1,1X,F5.1,1X,F7.3,1X,F6.2,1X,F7.2,1X,F7.2)
FORMAT 2 (16X, F5.1,1X,F5.1,1X,F7.3,1X,F6.2,1X,F7.2,1X,F7.2)
FORMAT 3 (16X, F5.1,1X,F5.1,1X,F7.3,1X,F6.2,1X,F7.2,1X,F7.2)
THRESHOLD 0.3
Keywords ahead of the READ records should look familiar.
Note that for the site id on the LOCATION record is 99999; since there usually is no ID associated with site-specific data, any NUMERIC value can be entered – no alphabetic characters.
The adjustment for GMT to LST is zero since the data are already on local STANDARD time.
READ – mandatory, repeatable
The number after each READ is the record_index and the variable names follow.
Since there are three heights (10, 50, 100 meters), the ‘vector’ variables have 01,o2, and 03 attached corresponding to the 3 levels.
Although the date and time are repeated on every record, it is only read on the first record of the hour; though, there is no reason you cannot read it every time.
FORMAT – mandatory, repeatable
The number after each format is the record_index and corresponds to the READ above.
On the first record of the hour, the date and time group are two digits, followed by a blank (I2,1X) – shorthand notation says to repeat this 4 times.
Equally valid would have been I2,1X, I2,1X, I2,1X, I2,1X.
The 4X says skip that 5th field.
Read the height σA, σw, temperature, wind direction, wind speed.
Do this again for the second record for the hour, but skip over the date time (16X).
Do this again for the third record for the hour, but skip over the date time (16X).
THRESHOLD – mandatory, non-repeatable
0.3 meters/second – below this value, AERMET will consider site-specific winds to be calm.
This value cannot exceed 1.0 meter/second.

31. The Control File - ONSITE
An example for the ONSITE pathway – an alternative:
ONSITE
DATA ONSITE.MET
QAOUT EX02_OS.OQA
XDATES 88/3/1 TO 88/3/10
LOCATION W 41.3N 0
READ 1 OSDY OSMO OSYR OSHR HT01 SA01 SW01 TT01 WD01 WS01
READ 2 OSDY OSMO OSYR OSHR HT02 SA02 SW02 TT02 WD02 WS02
READ 3 OSDY OSMO OSYR OSHR HT03 SA03 SW03 TT03 WD03 WS03
FORMAT 1 FREE
FORMAT 2 FREE
FORMAT 3 FREE
THRESHOLD 0.3
Since each field is separated by a blank, reading it as FREE format works here, but notice that we do have to read the date and time on each record
Look at the data – are they FREE format for every record? What would happen if the column in front of the field with the were deleted for all records and you tried to read it FREE format?

32. The Control File - ONSITE
ONSITE (cont’d)
Several keywords that were not used above are explained here
AUDIT: Identifies the variables to QA beyond the default variables
AUDIT osname1 … osnameN
RANGE: Set new upper, lower bounds for the QA and missing indicator
RANGE osname lower_bound <[=] upper_bound missing_indicator
NO_MISSING: Suppresses missing data QA messages to the MESSAGE file and does not tally the number missing for the QA’d variables
NO_MISSING osname1 osname2 … osnameN
ONSITE (cont’d)
AUDIT: Optional, repeatable
osname: Internal 2-character (vectors) or 4-character (scalars) AERMET variable names defined in Table B-3 of the Appendix in the AERMET User’s Manual.
For the vector variables, such as wind speed and temperature, only the first two characters should be specified, such as WS and TT.
Each variable has a default set of values for these parameters – see Table B-3.
Default variables: temperature (TMPD), wind speed (WSPD), wind direction (WDIR) (AERMET names are in parentheses).
RANGE: Optional, repeatable
osname: Internal AERMET names (see AUDIT)
lower_bound: Specify the (new) lower bound for sfname
<[=]: Symbol indicating lower bound less than upper bound and optionally [=] to include the endpoints
upper_bound: Specify the (new) upper bound for sfname

33. The Control File - ONSITE
ONSITE (cont’d)
Several keywords that were not used above are explained here
DELTA_TEMP: Identifies the lower and upper heights (in that order) used for DT01
DELTA_TEMP index lower_height upper_height
OBS/HOUR: Number of time periods per hour the site- specific data are reported
OBS/HOUR n_obs
OSHEIGHTS: Heights at which the site-specific data (vector data) are observed
OSHEIGHTS height1 … heightN
ONSITE (cont’d)
DELTA_TEMP: Optional, repeatable
index: Either 1, 2, or 3 – since only DT01 is in use at the moment, this index can only be 1
lower_height, upper_height: Heights of lower and upper levels, expressed in meters.
OBS/HOUR: Optional, non-repeatable (mandatory if observations are more frequent than hourly)
n_obs: Number of observations per hour.
Site-specific data may be reported more frequently than once per hour; this keyword lets AERMET know this and AERMET will compute an appropriate hourly average
Each hour MUST contain the same number of observation periods, even if it means creating ‘bogus’ records of missing data, for AERMET to process the data correctly
OSHEIGHTS: Optional, repeatable (mandatory if heights are not included in the data)
There may be a time when the heights in the data are not present . This keyword helps those situations.
Specify heights from lowest to highest, in meters.
Can the OSHEIGHTS be specified if there are heights in the data file?
Yes, can be used to override the heights in the data file
For example, if the data file has heights at 10, 50, and 100 meters, but the user knows the lower level is really at 9 meters, use this keyword to override the heights in the data file (note: AERMET will not physically replace the value(s) in the data file but will carry this information through to the boundary layer calculations

34. The Control File - MERGE
MERGE pathway and keywords
The section instructs AERMET how to process the two or three or four different files and combine the data into 1-day blocks
Two keywords associated with MERGE
OUTPUT: File to store the merged data
OUTPUT merged_data_filename
XDATES: Specifies the date range to include in the merged file
XDATES YB/MB/DB [TO] YE/ME/DE
MERGE Pathway
We’ve seen both of these structures before.
OUTPUT: Mandatory, non-repeatable
Follow the standard operating system file naming procedures.
XDATES: Optional, non-repeatable
If omitted, the earliest date found in the files being merged is used as the start point and processing continues for 367 days.
Can be used to merge multi-year data files.

35. The Control File - MERGE
MERGE (cont’d)
What files are merged?
SURFACE, UPPERAIR, ONSITE
Hourly averaged 1-minute ASOS data
How are the input files to the merge process specified?
Use the appropriate pathway with the QAOUT keyword on a separate record
Reminder: The ASOS1MIN keyword should be included on the SURFACE pathway when hourly-averaged 1-minute ASOS data are to be used
MERGE (cont’d)
The surface, upperair, and onsite meteorological data, as well as 1-minute wind data, when specified. Each data type to be used should be specified on the appropriate pathway as explained previously.

36. The Control File - MERGE
MERGE – an example
JOB
REPORT MERGE.RPT
MESSAGES MERGE.MSG
UPPERAIR
QAOUT UAQAOUT.DAT
SURFACE
QAOUT SFQAOUT.DAT
ASOS1MIN PVD_1min.dat
ONSITE
QAOUT OSQAOUT.DAT
MERGE
OUTPUT PVD.MRG
XDATES 1996/12/01 TO 1996/12/31
MERGE (cont’d)
By using the QAOUT keyword for each pathway, MERGE can locate and process each of the three input files PLUS the hourly-averaged 1-minute ASOS data and save the results in the file PVD_ISHD.MRG
A full year of data, from January 1, 2005 through December 31, 2005
There is site-specific data (ONSITE). Where are the READ and FORMAT records? How did AERMET know how to read it?
AERMET writes the control file records to the beginning of each output file in Stage 1 and Stage 2 and reprocesses some of those records. We will take a look at them in a different session.

37. The Control File - METPREP
METPREP pathway and keywords
The section instructs AERMET how to process the merged data, make all the boundary layer calculations, and create the two files required by AERMOD
An extensive array of keywords; we will look only at a subset in detail
DATA: File of merged data
DATA merged_data_filename
XDATES: Specifies the date range to process
XDATES YB/MB/DB [TO] YE/ME/DE
LOCATION: OBSOLETE – if present (e.g. in older control files), it is ignored
METPREP Pathway
We’ve already seen both these structures before.
DATA: Mandatory, non-repeatable
merged_data_filename: The name of the file in which the merged data are located; follow the operating system naming convention.
XDATES: Optional, non-repeatable
If omitted, the earliest date found in the files being merged is used as the start point and processing continues for 367 days.
Can be used to merge multi-year data files.
YB/MB/DB: BEGINNING year, month, day to extract – the slash (/) between fields is required.
There can be NO BLANKS in this string.
YB can be the 2-digit or 4-digit format for the year.
[TO]: An optional word to make the record more readable
YE/ME/DE: ENDING year, month, day to extract – the slash (/) between fields is required.

38. The Control File - METPREP
METPREP (cont’d)
OUTPUT: File of surface and near-surface parameters
OUTPUT parameter_filename
PROFILE: File of multi-level data
PROFILE profile_name
NWS_HGT: NWS instrument height, in meters
NWS_HGT variable_name instrument_height
FREQ_SECT: Indicates the number of surface characteristics to be specified, by wind direction and time period
FREQ_SECT frequency number_of_sectors
METPREP (cont’d)
OUTPUT: Mandatory, non-repeatable
parameter_filename: Name of the file of the surface-based parameters; follow the operating system naming convention.
Most parameters are calculated by AERMET, but the winds and temperature, as well as a few other parameters, are included for reviewing the results.
PROFILE : Mandatory, non-repeatable
profile_file: File with multi-level data; follow the operating system naming convention.
If site-specific data are present, it is a repeat of those data.
If there is no site-specific data or the site-specific data are missing for the hour, then a 1-level profile using NWS data is created for the hour.
NWS_HGT – optional/mandatory, non-repeatable
NWS_HGT is mandatory only if substitution of NWS data is specified (see METHOD keyword).
variable_name: The weather variable for which a height may be required.
WIND is currently the only valid variable_name.
instrument_height: The height, in meters, of the instrumentation for the variable identified.

39. The Control File - METPREP
METPREP (cont’d)
SECTOR: Defines a single wind direction sector, in degrees, for which the site characteristics apply
SECTOR sector_index beginning_direction ending_direction
SITE_CHAR: Defines the direction dependent albedo, Bowen ratio, and roughness length
SITE_CHAR frequency_index sector_index albedo Bowen_ratio roughness
METHOD: Specifies the processing methodology/option for a particular variable
METHOD atmospheric_variable option
METPREP (cont’d)
SECTOR: Mandatory, repeatable
sector_index: The sector number that links a specific set of site characteristics to a specific wind sector (cannot be greater than the number specified on the FREQ_SECT keyword).
beginning_direction: Defines the beginning direction of the sector and is considered part of the sector.
ending_direction: Defines the ending direction of the sector and is considered part of the NEXT sector.
Each occurrence of the SECTOR keyword defines one sector.
The full set of sectors defined must span a full 360 degree circle.
Sectors should be defined in a clockwise direction (north is 0 and 360 degrees)
Each sector must span a minimum of 30 degrees and sectors may not overlap.
The ending_direction of one sector should be the beginning _direction of the adjacent sector and the beginning _direction of a sector must match the ending_direction of the previous sector (when 2 or more sectors are defined).
The beginning_direction is part of the sector (the end_direction is part of the next).
A sector can span north, e.g., 340 to 20.
To define sectors, look at influences of land use, land cover, and terrain, on the order of 1 kilometer upwind of the tower.

40. The Control File - METPREP
An example for the METPREP pathway
METPREP
XDATES /12/01 TO 96/12/31
DATA HOUSTON.MRG
METHOD REFLEVEL SUBNWS
METHOD WIND_DIR RANDOM
NWS_HGT WIND
OUTPUT HOUSTON.SFC
PROFILE HOUSTON.PFL
FREQ_SECT ANNUAL 1
SECTOR
SITE_CHAR
METPREP (cont’d)
Note that the METHOD keyword appears twice, once to substitute NWS winds and temperature and again to control randomizing NWS wind direction.
The NWS wind instrument is located at a height of 6.1 meters (20 feet).
The site characteristics will apply for the entire year for all directions (ANNUAL 1).
When there is only one sector, the beginning and ending direction should be specified as 0 and 360.
The site characteristics are: albedo = 0.25, Bowen ratio = 0.70 (wet conditions), and roughness length of 0.15 meters.

41. The Control File - METPREP
An example of more extensive surface characteristics
FREQ_SECT MONTHLY 2
SECTOR
SECTOR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
SITE_CHAR
METPREP (cont’d)
NOTE: The multiple occurrences of the SITE_CHAR keyword appears one after another in a control file, but are displayed in two columns here to get them on one slide.
The site characteristics are monthly for 2 sectors (FREQ_SECT MONTHLY 2).
The two sectors are from 35° (included) to 225° (excluded) and from 225° (included) to 35° (excluded).
The site characteristics on the left are for January-December for the first sector and on the right for January-December for the second sector.

42. The Control File - METPREP
METPREP – additional keywords
AERSURF, AERSURF2: Files of surface characteristics (rather than directly in the METPREP pathway)
AERSURF primary_surfchar_filenam
AERSURF2 secondary_surfchar_filnam
FREQ_SECT2: Defines frequency and number of sectors for a secondary set of surface characteristics
FREQ_SECT2 frequency number_of_sectors
SECTOR2: Defines a single wind direction sector, in degrees, for which the secondary set of site characteristics apply
NWS_HGT variable_name instrument_height
SITE_CHAR2: Defines the secondary set of direction dependent albedo, Bowen ratio, and roughness length
FREQ_SECT frequency number_of_sectors
METPREP (cont’d)
Notice here is that a secondary set of surface characteristics are defined under certain conditions,. That is, when both site-specific data AND hourly NWS data are present
If ONLY site-specific data are present or if ONLY NWS data are present, the surface characteristics are considered the primary set and are defined with keywords FREQ_SECT, SECTOR, and SURF_CHAR.
IF BOTH site-specific and hourly NWS data are present,
The surface characteristics for site-specific data are considered the primary set and defined with keywords FREQ_SECT, SECTOR, and SURF_CHAR, and
The surface characteristics for hourly NWS data are the secondary set and defined with keywords FREQ_SECT2, SECTOR2, and SURF_CHAR2.
AERSURF, AERSURF2: Optional, non-repeatable
primary_surfchar_filenam, secondary_surfchar_filenam: Name(s) of file(s) with the surface characteristic information.
These optional parmaters are useful if AERSURFACE output file(s) is (are) available in which case file names can be specified rather than taking AERSURFACE output and copying/pasting in to Stage 3 control file.
FREQ_SECT2, SECTOR2, SITE_CHAR2: Optional/mandatory, repeatable
Mandatory if both site-specific and NWS data are used; otherwise optional.
See the discussions on FREQ_SECT, SECTOR, and SITE_CHAR – same rules apply.
Number and definition of sectors can differ between primary and secondary.

43. The Control File - METPREP
METPREP – additional keywords
THRESH_1MIN: Sets the minimum wind speed (meters/second) for winds calculated from the 1-minute ASOS data below which the wind is treated as calm
THRESH_1MIN threshold_speed
UAWINDOW: Defines the time window to use to select the upper air sounding to be used in the calculations
UAWINDOW window_begin window_end
MODEL: Name of the model for which the data are processed; default is AERMOD (keyword is not used since there is only one model)
MODEL model_name
METPREP (cont’d)
THRESH_1MIN: Optional, non-repeatable
threshold_speed: Minimum wind speed in meters per second.
UAWINDOW: Optional, non-repeatable
NOTE: soundings are reported in GMT, but AERMET converts the in Stage 1 to local time so the soundings can be merged into the correcet day in Stage 2; in Stage 3, the time must be converted back to GMT to identify the preferred sounding time.
window_begin: The number of hours relative to the preferred sounding time (e.g GMT) to start the search.
window_end: The number of hours relative to the preferred sounding time (e.g GMT) to end the search.
Endpoints are included in the window.
Preferred sounding time – internal to AERMET based on longitude (west and east); the Addendum to the AERMET User’s Guide has more information on the upper air window and preferred sounding time.
By default, AERMET searches the 1100 – 1300 GMT window to identify the sounding to use.
Sometimes the sounding is released late so the search window can be adjusted/widened . For example, in the United States UAWINDOW will search from 1200 (the preferred sounding time) to 1500 GMT.
For multiple soundings in the search window, priority is given to soundings before the preferred time, before the start or continued development of the CBL .
With the globalization of AERMET, a user may need to redefine the window for a particular location. (e..g., UAWINDOW 0 3).
MODEL – optional, non-repeatable
It was originally thought that more processing might be for more than one model, but this keyword is not in use and the program is hard coded for AERMOD.

44. Special Topics Upper Air Sounding Selection Threshold Wind Speeds
ASOS Wind Truncation
File Formats
Running with Site-specific Data Only
These topics will be covered on the following slides

45. Upper Air Sounding Selection
AERMET originally developed to work with NWS upper air sounding data available in the United States and North America
Globalized with version 11059, and can run anywhere in the world
Preferred sounding time is prior to sunrise, before the convective mixed layer begins to develop
1200 GMT (current day) in U.S
0000 GMT in Europe, Africa, parts of Asia
1200 GMT (previous day) in Far East, Australia
AERMET provides an option base the preferred sounding on time of sunrise (METHOD keyword)
Special Topics – Upper Air Sounding Selection
Since the reported upper air observation time in the U.S. is known to vary slightly, AERMET defined a default “sounding window” of ±1 hour from the preferred time, i.e., AERMET accepted the 11Z, 12z, or 13Z sounding.
A globalized AERMET made this ‘window’ unworkable for other parts of the world.
UAWINDOW: Optional, non-repeatable
NOTE: soundings are reported in GMT, but AERMET converts them in Stage 1 to local time so the soundings can be merged into the correct day in Stage 2; in Stage 3, the time must be converted back to GMT to identify the preferred sounding time.
window_begin: The number of hours relative to the preferred sounding time (e.g GMT) to start the search.
window_end: The number of hours relative to the preferred sounding time (e.g GMT) to end the search.
The preferred sounding time is determined internally in AERMET based on longitude (west and east). The Addendum to the AERMET User’s Guide has more information on the upper air window and preferred sounding time.
By default, AERMET searches the 1100 – 1300 GMT window to identify the sounding to use. In the U.S. the equivalent usage of the UAWINDOW keyword would look like this: UAWINDOW
To force AERMET to accept only soundings corresponding to the reference sounding time, use: UAWINDOW 0 0.

46. Upper Air Sounding Selection
Special Topics – Upper Air Sounding Selection
This map shows the preferred sounding times across the globe. The preferred sounding time is across the top of the map.
The bottom of the map shows time zones with Greenwich at 1200 GMT

47. Threshold Wind Speed Two in AERMET
For site-specific data
For hourly averaged 1-minute ASOS data
Standard cup anemometer has a nominal starting threshold of about 2 knots
Sonic anemometers have virtually no starting threshold
Minimum acceptable wind speed threshold for site-specific meteorological monitoring is 0.5 m/s under current EPA guidance
THRESHOLD keyword – for site-specific data on ONSITE pathway
THRESH_1MIN – for hourly averaged 1-minute ASOS data
To avoid imposing a more stringent requirement on data derived from 1-minute ASOS data than would be required for a site-specific monitoring program
Special Topics – Threshold Wind Speed
For additional information, refer to the Meteorological Monitoring Guidance for Regulatory Modeling Applications (February 2000).

48. ASOS Wind Truncation
Applies only to the NWS hourly surface weather observations
The wind speed is truncated – NOT rounded
3.4 m/s is truncated to 3 m/s
3.7 m/s is truncated to 3 m/s, not rounded to 4 m/s
Introduces a bias
AERMET compensates for this bias by adding m/s (0.5 knot)
Can be overridden with METHOD keyword
METHOD ASOS_ADJ NO_ADJ
Special Topics – ASOS Wind Truncation
As mentioned in the presentation for AERMINUTE. NWS winds are truncated (no rounded) and stored as whole knots. This introduces a bias of lower speeds in the meteorological data than is reality.
AERMET compensates by adding ½ knot or m/s
This wind speed adjustment is applied, by default, during Stage 3 processing to wind speeds substituted from 1-minute ASOS wind data as well as those substituted from standard NWS/FAA surface data determined to be ASOS winds based on the ASOS commission date.
This adjustment to the wind speed can be overridden using the METHOD keyword:
METHOD ASOS_ADJ NO_ADJ
Where:
ASOS_ADJ refers to the the wind speed adjustment and NO_ADJ indicates the adjustment should not be applied.

49. File Formats Active Date Range for NWS Hourly Surface Files
AERMET checks for consistency between the date of the observation and the range of dates for which the NWS format is considered to be active and valid
If outside the valid range, assumed to have been reformatted from some other data format
Concerns over converting ASOS-derived cloud cover to SAMSON and SCRAM (pre-ASOS) formats
Reformatting is discouraged
NWS Surface Format
Start Date
End Date
CD-144
---
12/31/1995
HUSWO
1/1/1990
ISHD
SAMSON
1/1/1961
12/31/1990
SCRAM
1/1/1984
12/31/1992
TD-3280
Special Topics – File Formats
Active Date Range
AERMET contains a built-in table to perform a check between the date of the observation and the range of dates for which the NWS format is considered to be valid.
AERMET issues a warning if the data are outside the active date range
If the data have been reformatted and data are not in the active date range for the format, inconsistencies may result with data processed for the same station and dates input in their native format, in particular cloud cover.
Opaque and total cloud cover set to missing for observations extracted from SAMSON and SCRAM formats for which the observation date falls on or after the ASOS commission date.

50. Using Only Site-Specific and Upper Air
Running AERMET with site-specific data and upper air soundings is possible, and may be necessary in regions where NWS stations are sparsely distributed
North Slope, Alaska
Only if all the necessary variables are present including
Wind speed & direction
Temperature
Solar radiation and temperature difference
‘Preferred’ sounding
Special Topics – Running with site-specific data and upper air soundings
In areas of sparse NWS hourly observation, the only option may be to use site-specific data and upper air soundings.
As long as the minimum data requirements listed are met, this is not a problem.
You may need to fool AERMET by including an empty hourly file.

51. Using Only Site-Specific Data
Running AERMET with site-specific data only is possible
Only if all the necessary variables are present including
Wind speed & direction
Temperature
Cloud cover OR Solar radiation and temperature difference
Heat flux and friction velocity
Mixing height
Not easy to collect hourly observations of mixing heights
Special Topics – Running with site-specific data only
AERMOD can be run with site-specific data only as long as the necessary meteorological parameters listed are included in the site-specific data file.
Hourly observations of mixing heights require expensive equipment; it may be difficult to interpret where to set mixing height.

52. Running AERMET Three step (stage) process
AERMET expects the control file to be named AERMET.INP
AERMET determines the processing to be performed based on the pathways included
Windows-like environment – double-click aermet.exe
Command prompt environment – type ‘aermet’ (without quotes) and press return
Running AERMET
Since each stage must be run separately, AERMET requires that there be three separate input control files, though each stage requires the control file to be named “AERMET.INP.”
Therefore, it is necessary to rename each control file to “AERMET.inp” before running each stage of AERMET.
You can execute AERMET by double-clicking on the program file, aermet.exe, in a Microsoft Windows Explorer window.
You can also run AERMET from the command-prompt by typing the path and filename (aermet.exe) at the prompt.
Typically, AERMET is run via a Windows batch file that renames the control files and executes each stage of AERMET sequentially..

53. Reviewing AERMET Output
Report and Messages files
‘Surface’ and ‘Profile’ files
Minimum/maximum values
Temporal consistency – daytime vs. nightime
Reviewing AERMET Output
This is only a brief look at the AERMET output. We will look at the files in more detail during the hands-on.
Messages file: Informational, Warning, Error, and QA messages.
Informational: General information about the processing such as number of records processsed.
Warning: A problem was detected but is not severe enough to warrant an error condition; the warning should be investigated to be sure it does not affect the results.
Error: Often identifies an error in the control file prior to processing data; problem reading/writing the data.
QA: Messages generated during the QA of the data – generally upper/lower bound violations. Refer to Appendix D of the user’s guide addendum for a complete list.
Report file: A summary of the processing including counts of messages, including QA results of variables (default and specified by the user).
‘Surface’ file: The file of hourly atmospheric parameters required by AERMOD.
One record per hour.
Review all or a portion of the data to be sure it does not look suspect (e.g., values too large or too small for the atmospheric conditions) or there are long periods of missing data.
Do the values look reasonable for the time of day, e.g., is the heat flux upward (positive) during the day or does it become positive in the middle of the night; are the friction velocity and convective velocity scale of reasonable magnitude?
More information on how to review the data during the hands-on.
‘Profile’ file: One or more levels of data either from site-specific or NWS data.
Mostly a ‘pass-through’ file – no processing is performed or new parameters calculated and output.
If site-specific data is processed, then this file consists of the one or more levels of a data collected during the monitoring program.
If there are no site-specific data or it is missing for the hour, then NWS data is substituted (if METHOD REFLEVEL SUBNWS is included in the Stage 3 control file).