Below are some examples of this header format in action. The first is a sounding from the Denver Airport location
39.78000
-104.86000
72469
DENVER/STAPLETON INT., CO. / U.S.A.
FM-35 TEMP
GTS (ROHK) UKUS09 KWBC 051200 RRA
1626.00000
1
-888888
-888888
890
-888888
T
F
F
-888888
-888888
20080205120000
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
This is what it looks like on a single line. Notice that there is no separation between the fields, so sometimes they run together! Look at, for instance, the longitude and ID:
39.78000 -104.8600072469 DENVER/STAPLETON INT., CO. / U.S.A. FM-35 TEMP GTS (ROHK) UKUS09 KWBC 051200 RRA 1626.00000 1 -888888 -888888 890 -888888 T F F -888888 -888888 20080205120000-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0
The next example is a buoy observation from the Antarctic Ocean, west of the Antarctic Peninsula
-71.86300
-125.59700
-7777
Platform Id >>> 71656
FM-18 BUOY
GTS (ROHK) SSVX07 LFVW 051100
0.00000
6
-888888
-888888
564
-888888
F
F
F
-888888
-888888
20080205110000
97940.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
97940.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
This example is a wind profiler observation from northeast of Anchorage, Alaska.
36.88000
-89.97000
-----
ID BLMM7
FM-32 PROFILER
MADIS NOAA Profiler Network NWS N
130.00000
258
0
0
1
0
F
F
F
-888888
-888888
20080205120000
-999999.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-999999.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
This example is a satellite retrieval observation from the northern Atlantic Ocean, about 2000km east of Bermuda.
Louisiana State University FM-111 (GPSPW, 1 level). Note that the PW information itself was stored in the "header" record, so only other observations from this station (such as surface pressure) can be found in the data record:
The decimal latitude of the observation location, relative to the equator.
Mandatory
31.12000
Positive values are north of the equator, negative values to the south. Must be in the range [-90.00000, 90.00000].
Longitude
F20.5
The decimal longitude of the observation location, relative to the prime meridian.
Mandatory
31.12000
Negative values are west of the prime meridian, positive values to the east. Must be in the range [-180.00000, 360.00000] (values between 180 and 360 will be subtracted by 360 prior to being re-encoded for ob.ascii).
ID
A40
The ID of the observation.
Optional
3009S 13625E
• For buoy observations, this field can be used as an alternate way to include elevation information (see the section on elevation) • For SATOB (FM-88) observations, if this field contains the text "AVHRR", this indicates that WRFDA should treat it as a POLARAMV observation, rather than a GEOAMV observation. • For all other observations this field is only included for human readability. Can be any text: for example, the type of instrument used.
Name
A40
The name of the observation.
Optional
LINZ/HOERSCHINGFLUGHAFEN / AUSTRIA
• For SATOB (FM-88) observations, if this field contains the text "MODIS", this indicates that WRFDA should treat it as a POLARAMV observation, rather than a GEOAMV observation. • For all other observations this field is only included for human readability. Can be any text: often used to describe the observation location name
Platform (FM‑Code)
A40
The FM-code of the observation, followed by an optional text description of the observation.
Mandatory
FM-97 AIREP
The first 3 characters must be exactly "FM-". Characters 4–6 should be a valid FM Code, either a 3-digit number or a 2-digit number followed by a space. The remaining 34 characters are typically a text description of the platform (e.g. "SYNOP", "SHIP", "AIREP", etc.), but theoretically can be any text.
Source
A40
The source of the observation.
Optional
MADIS NOAA Profiler Network NWS N
This field is only included for human readability. Can be any text: often used to describe the source or data stream from which the observation was obtained.
Elevation
F20.5
The elevation of the observation above sea level in meters.
Number of errors reported in writing the observation
Unused
0
Warnings
I10
Number of warnings reported in writing the observation
Unused
0
Sequence number
I10
The sequential order of this observation type/set
Optional
523
This field is only used as one of the "tiebreakers" for deciding which observation header will be kept when merging duplicate obs. It is assumed that lower numbers are more recent observations.
Duplicates
I10
Number of duplicate observations
Unused
0
Is sounding
L10
Logical flag: true if observation has multiple levels
Unused
F
Bogus
L10
Logical flag: true if observation is a "bogus" observation
Optional
T
This field is only used for some internal quality control checks that should not apply to "bogus" type observations.
Discard
L10
Logical flag: true if observation should be discarded
Optional
F
This field can be used to specify the observation should not be used. Will not be written to WRFDA-format ASCII file.
Unix Time
I10
Unix Time in seconds
Optional
1497388306
This field is only used as one of the "tiebreakers" for deciding which observation header will be kept when merging duplicate obs.
Julian Day
I10
Julian Day
Optional
2457918
This field is only used as one of the "tiebreakers" for deciding which observation header will be kept when merging duplicate obs.
Date string
A20
The date as a string of numerical characters (YYYYMMDDhhmmss)
Mandatory
20080205120000
This is the date used for checking against the namelist-specified time window. Observations outside of the specified time window will be rejected.
Sea level pressure/QC
F13.5 I7
Sea level pressure (Pa) and quality control flag
Optional
100459.85900 0
Optional for bogus observations (FM-135), unused for all others
Reference pressure/QC
F13.5 I7
Reference pressure (Pa) and quality control flag
Mandatory for some observations
100000.00000 0
Mandatory for SATEM observations (FM-86): reference pressure for geopotential thickness. Unused for all other observation types
Ground temperature/QC
F13.5 I7
Ground temperature (K) and quality control flag
Unused
288.50000 0
SST/QC
F13.5 I7
Sea surface temperature (K) and quality control flag
Unused
275.80000 0
PSFC/QC
F13.5 I7
Surface pressure (Pa) and quality control flag
Optional
98150.00000 0
• Optional for METAR (FM-15,16) if calc_psfc_from_QNH=true; this entry should be the altimeter setting (QNH, and OBSPROC will calculate the surface pressure from that value. • Used for consistency checks for sounding-type observations (FM-32 through 38). • Unused for other observation types.
Precipitation/QC
F13.5 I7
Precipitation accumulation (cm) and quality control flag
Unused
1.80000 0
Max temp/QC
F13.5 I7
Maximum daily temperature (K) and quality control flag
Unused
305.10000 0
Min temp/QC
F13.5 I7
Minimum daily temperature (K) and quality control flag
Unused
249.00000 0
Min night temp/QC
F13.5 I7
Minimum overnight temperature (K) and quality control flag
Unused
249.00000 0
3H pressure tendancy/QC
F13.5 I7
3-hour pressure tendency (Pa) and quality control flag
Unused
150.00000 0
24H pressure tendancy/QC
F13.5 I7
24-hour pressure tendency (Pa) and quality control flag
Unused
-400.00000 0
Cloud cover/QC
F13.5 I7
Cloud cover and quality control flag
Optional
0.00000 0
Optional for SATEM observations (FM-86): Values greater than 10 will be rejected as cloudy observations. Unused for all other observation types
Ceiling/QC
F13.5 I7
Height of cloud base (m) and quality control flag
Unused
4342.00000 0
PW or ZTD / QC
F13.5 I7
Precipitable water/ZTD and quality control flag
Mandatory for some observations
3.04000 0
Mandatory for GPSPW (FM-111) and GPSZTD (FM-114): values are in centimeters, and the QC field is in tenths of a millimeter (see the section on GPS observations for more details. Unused for all other observation types. These are the only fields which are truly optional (can be left out rather than filled with missing-data flags).
Observed pressures less than 850 hPa will be discarded.
FM‑15 FM-16
METAR SPECI
P and/or H
Sp,Dr,T,RH†
Td,U,V,Th
FM‑18 FM-19
BUOY
(none)
P,H,T,Td,Sp,Dr,U,V,RH†
Th
Unlike most other observations, if surface pressure and elevation are included in the header record, the observation will be used regardless of the inclusion of other fields Observed pressures less than 850 hPa will be discarded.
FM‑32 FM-33 FM-34
PILOT PILOT SHIP PILOT MOBIL
P and/or H
Sp,Dr
T,Td,U,V,RH,Th
FM‑35 FM-36 FM-37 FM-38
TEMP TEMP SHIP TEMP DROP TEMP MOBIL
P and/or H
Sp,Dr,T,Td,RH
U,V,Th
FM‑42
AMDAR
P and/or H
Sp,Dr,T,Td,RH†
U,V,Th
Aircraft height will be converted to pressure if higher than 3000m above ground level
FM‑86
SATEM
P,H,Th
(none)
T,Td,Sp,Dr,U,V,RH,Th
FM‑88
SATOB
P,Sp,Dr
(none)
H,T,Td,U,V,RH,Th
FM‑96 FM-97
AIREP
P and/or H
Sp,Dr,T,Td,RH†
U,V,Th
Aircraft height will be converted to pressure if higher than 3000m above ground level
FM‑101
TAMDAR
P and/or H
Sp,Dr,T,Td,RH
U,V,Th
FM‑111
GPSPW
(none)
(none)
P,H,T,Td,Sp,Dr,U,V,RH,Th
GPS PW data is stored in the header; see relevant section for details.
FM‑114
GPSZD
(none)
(none)
P,H,T,Td,Sp,Dr,U,V,RH,Th
GPS ZTD data is stored in the header; see relevant section for details.
FM‑116
GPSRF
P,H,T,Td,RH
(none)
U,V,Sp,Dr
The GPSRF data should be stored as follows:
P: pressure
H: height
T: temperature
Td: refractivity
Sp: impact parameter / 1000
Dr: azimuth
U: latitude
V: longitude
RH: Bending angle * 1.e7
Only pressure, height, temperature, refractivity, and bending angle are used by WRFDA.
FM‑121
SSMT1
P and/or H
T
Sp,Dr,Td,U,V,RH,Th
FM‑122
SSMT2
P and/or H
T
Sp,Dr,Td,U,V,RH,Th
FM‑132
PROFILER
P and/or H
Sp,Dr
T,Td,U,V,RH,Th
FM‑133
AIRSRET
P and/or H
T,Td,RH
Sp,Dr,U,V,Th
FM‑135
BOGUS
P and/or H
Sp,Dr,T,Td,RH†
U,V,Th
FM‑281
QSCAT
H,Sp,Dr
(none)
T,Td,U,V,RH,Th
†RH observations will be unused unless the observation also contains P and T; these variables are required for the calculation of the saturation vapor pressure.
Here is an example GPSPW observation (the same shown earlier). Important fields are bolded, unused fields have a gray background. The observation is for 3.04 cm. Note that the QC field is 0, so OBSPROC will assign a default value of 2 (0.2 mm)
Lat.
Lon.
ID
Name
Platform
Source
Elevation
Valid fields
Num. errors
Num. warn.
Seq. number
Num. dup.
sound
bogus
Discard?
Unix time
Jul. day
Date
SLP, QC
Ref Pres., QC
Ground Temp, QC
SST, QC
SFC Pres, QC
Precip, QC
Dly Max T, QC
Dly Min T, QC
Ngt Min T, QC
3hr Pres Chg, QC
24hr Pres Chg, QC
Cld cvr, QC
Ceil, QC
Precipitable Water, QC
30.40742
-91.18026
00001
1LSU
FM-111 GPSPW
HOURLY_PWV.LLH
20.91000
0
0
0
0
0
F
F
F
0
36
20080205114500
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
3.04000 0
Pressure (Pa)
QC
Height (m)
QC
Temperature (K)
QC
Dew point (K)
QC
Wind speed (m/s)
QC
Wind direction (deg)
QC
Wind U (m/s)
QC
Wind V (m/s)
QC
Relative humidity (%)
QC
Thickness (m)
QC
101180.00000
0
20.91000
0
295.04999
0
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
And here is the entire observation as it should appear in LITTLE_R format:
Here is an example GPSZTD observation (a fake observation with fake values). Important fields are bolded, unused fields have a gray background. The observation is for 250.20 cm. Note that the QC field is 0, so OBSPROC will assign a default value of 2 (0.2 mm)
Lat.
Lon.
ID
Name
Platform
Source
Elevation
Valid fields
Num. errors
Num. warn.
Seq. number
Num. dup.
sound
bogus
Discard?
Unix time
Jul. day
Date
SLP, QC
Ref Pres., QC
Ground Temp, QC
SST, QC
SFC Pres, QC
Precip, QC
Dly Max T, QC
Dly Min T, QC
Ngt Min T, QC
3hr Pres Chg, QC
24hr Pres Chg, QC
Cld cvr, QC
Ceil, QC
Zenith Total Delay, QC
30.40742
-91.18026
Fake observation for GPSZTD test
Fake observation for GPSZTD test
FM-114 GPSZTD
Fake observation for GPSZTD test
20.91000
0
0
0
0
0
F
F
F
0
36
20080205114500
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
-888888.00000 0
250.20000 0
Pressure (Pa)
QC
Height (m)
QC
Temperature (K)
QC
Dew point (K)
QC
Wind speed (m/s)
QC
Wind direction (deg)
QC
Wind U (m/s)
QC
Wind V (m/s)
QC
Relative humidity (%)
QC
Thickness (m)
QC
101180.00000
0
20.91000
0
295.04999
0
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
-888888.00000
-888888
And here is the entire observation as it should appear in LITTLE_R format:
30.40742 -91.18026Fake observation for GPSZTD test Fake observation for GPSZTD test FM-114 GPSZTD Fake observation for GPSZTD test 20.91000 0 0 0 0 0 F F F 0 36 20080205111500-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888-888888.00000-888888 250.20600 0-888888.00000-888888
101180.00000 0 20.91000 0 295.04999 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0
-777777.00000 0-777777.00000 0 1.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0-888888.00000 0
1 0 0
Surface observation from a fixed land station Surface observation from a mobile land station
FM-13
SHIP
Surface observation from a sea station
FM-15 FM-16
METAR SPECI
Aerodrome routine meteorological report Aerodrome special meteorological report
FM-18 FM-19
BUOY
Buoy observation
FM-32 FM-33 FM-34
PILOT PILOT SHIP PILOT MOBIL
Upper-wind report from a fixed land station Upper-wind report from a sea station Upper-wind report from a mobile land station
FM-35 FM-36 FM-37 FM-38
TEMP TEMP SHIP TEMP DROP TEMP MOBIL
Upper-level pressure, temperature, humidity and wind report from a fixed land station
Upper-level pressure, temperature, humidity and wind report from a sea station
Upper-level pressure, temperature, humidity and wind report from a sonde released by carrier balloons or aircraft
Upper-level pressure, temperature, humidity and wind report from a mobile land station
FM-42
AMDAR
Automated aircraft report
FM-86
SATEM
Report of satellite remote upper-air soundings of pressure, temperature, humidity, and thickness
FM-88
SATOB
Report of satellite observations of wind, surface temperature, cloud, humidity and radiation
The first number simply multiplies the content that comes after it. For example, "10I5" indicates there are 10 I5 fields, 3F10.2 indicates there are 3 F10.2 fields, and 1L15 indicates there is just one L15 field (in which case, the 1 is optional and can be omitted).
The character indicates what the data type is. "F" for floating point number , "I" for integer, "A" for text/characters, and "L" for logical (true/false).
The rest of the content indicates how wide the field will be, and how the decimal point will be placed (if applicable). Floating point numbers are a little bit more complicated: F10.2 indicates the whole field will be 10 characters wide (including the decimal point), and there will be 2 characters after the decimal point. If the input data is less than that number of characters across, it should be padded at the beginning with the appropriate number of spaces.
Here are several examples to put this all in practice:
I8: An integer 8 characters across. Only numerical characters (0-9) or spaces can be included, otherwise there will be a read error. Valid possibilites include:
" 8"
" 0423"
"00010000"
" 42"
"12345678"
L5: A logical 5 characters across. Can be "T" or "F", padded with 4 spaces. Valid possibilities include:
" T"
" f"
A10: A character string 10 characters across. Can be any valid printable ASCII characters:
" 8"
" puppyface"
"?*Skjs-3`#"
"forty-two "
""
" !Q~w 1=2 "
F20.5: A floating point number 20 characters across. There should be 5 digits after the decimal point, and any extra space to the right of the decimal should be padded with zeros or spaces
For ship observations, the elevation for Great Lakes observations will be assigned from a set value for each lake based on the lake's standard elevation
For buoy observations, the elevation for these observations will be assigned from the table contained in the text file msfc.tbl (provided in the WRFDA/var/obsproc/ directory). For these observations, the first 5 digits of the "ID" field must correspond to one of the codes contained in that table.
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