Met Reader Manual

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MetReader: Documentation and User’s Guide
Hans F. Schwaiger
June 26, 2018

1

Introduction

MetReader is a library written in fortran 90 that provides an interface to numerical weather
prediction (NWP) data, or other forms of meteorological data, such as radiosonde or other
1-D data.
This library was originally written as a component of the USGS volcanic ash transport
and dispersion model, Ash3d. However, since it is useful for programs other than Ash3d, this
interface to NWP files is provided as a separate repository that can either be compiled as a
library or simply compiled directly with other source code.
NWP data are generally made available by agencies (NCEP, NOAA, NASA, etc.) in
a variety of formats (NetCDF, GRIB1, GRIB2, ASCII); each product having its own data
structure, naming convention, units, etc. This library isolates the calling program from the
peculiarities of interfacing with a particular NWP product. Data can be returned to the
calling program on the native grid of the NWP product, or on any grid needed by the calling
program. Projection and interpolation of NWP data to the required grid, along with any
rotation of velocity vectors to grid-relative, is calculated internally by MetReader.

2

Installation

This library requires two additional libraries made available on GitHub and USGS GitLab:
• HoursSince
This is a library that takes a date and time, and calculates the number of hours since
January 1, 1900 (or any artibrary base year).
(https://github.com/hschwaiger-usgs/HoursSince)
• projection
This is a library that calculates commonly-used projected coordinates.
(https://github.com/hschwaiger-usgs/projection)
These libraries are installed by default into /opt/USGS. If they are installed elsewhere,
then you will need to edit the makefile to point to your installation. Additionally, the default
makefile will build MetReader with both NetCDF and GRIB2 enabled. If either of these
libraries are unavailable on your system, you can deactivate those options by setting the
1

corresponding flags to F in the makefile. On a RHEL/CentOS system, you can install the
data format libraries by typing
sudo yum install netcdf netcdf-devel grib_api grib_api-devel
or for Ubuntu
sudo apt-get install libnetcdf* libgrib-api*
To compile MetReader as a library, simple type:
make all
This will build the requested components of the library. If GRIB2 is enabled, this will also
build the GRIB2 indexer, gen GRIB2 index. This is a tool that generates an index file of the
GRIB records which speeds access time to individual records substantially.
To install the library, module files and tools, edit the INSTALLDIR variable of the makefile
(the default is /opt/USGS) and type:
make install
This will also install scripts that can be used to download the 0.5 degree GFS forecast files
and the NCEP 2.5-degree Reannalysis files.
You will need to have write permission in ${INSTALLDIR} or install as root. Assuming
the libraries projection and hourssince are installed in the default location, installation
will result in the following directory structure:
/opt/USGS
|-- bin
|
|-- autorun_scripts
|
|
|-- autorun_gfs0.5deg.sh
|
|
|-- autorun_NCEP_50YearReanalysis.sh
|
|
|-- convert_gfs0.5deg.sh
|
|
|-- get_gfs0.5deg.sh
|
|
|-- get_NCEP_50YearReanalysis.sh
|
|
‘-- grib2nc.sh
|
|-- gen_GRIB2_index
|
|-- HoursSince1900
|
|-- ncMet_check
|
|-- ncMetSonde
|
|-- ncMetTraj_B
|
|-- ncMetTraj_F
|
‘-- yyyymmddhh_since_1900
|-- include
|
|-- metreader.mod
|
‘-- projection.mod
‘-- lib
|-- libhourssince.a
|-- libMetReader.a
‘-- libprojection.a
2

3

Usage

MetReader can read a variety of input data formats (1-D, 3-D, ASCII, NetCDF, GRIB2)
and provide access to the meteorological data on either the native grid of the NWP data, or
interpolated onto a finer regular grid. Before the meterological data can be accessible, several
preliminary steps must first be completed.

3.1

Preliminary meta-data

The calling program needs to prepare several parameters that define the type of meteorological
data to be read.
• iw :: windfile class (the distinction between 3 adn 4 will be obselete soon)
– 1 : 1-D wind sounding
– 2 : 3-D grid is read from a ASCII file
– 3 : single, multistep 3-D datafile
– 4 : multiple 3-D datafiles
– 5 : special case for NCEP 50-year reanalysis and NOAA reanalysis
• iwf :: windfile format number (linked to specific product in Table 8.2 of Appendix 8.2)
• igrid :: NCEP Grid ID
• idf :: Data file format code (ASCII, NetCDF, GRIB, etc)
– 1 : ASCII
– 2 : NetCDF
– 3 : GRIB Edition 2
– 4 : GRIB Edition 1 (Not yet implemented; used by NARR and NOAA-CIRES)
• iwfiles :: number of windfiles to be read
• SimStartHour :: The starting time needed given as hours since 1900-01-01 00:00Z
This can alternatively be given as hours since a different base year as described below.
• SimDuration :: duration needed in hours
Additionally, there are several other parameters that could be set, if needed.
• MR BaseYear :: The default value for this is 1900, but must be reassigned by the calling
program if the NWP files to be read contain data prior to 1900.
• MR useLeap :: The default is .true. but can be set to .false. if the NWP files use a
calendar without leap years (e.g. some paleoclimate CAM files)
• MR iHeightHandler :: This code defines how MetReader behaves when values at altitudes above those available in the NWP files are requested. Default value is 2.
3

– 1 : Stop the program
– 2 : Return wind values equal to the value at the highest available node; temperature values remain constant from 11-20 km, then increase by 2◦ C/km.
• MR iwf template :: This is the file name of the template for the custom NetCDF files
described in section 5. This is only required to be set if iwf=0. Currently, the custom
windfile specification is only implemented for idf=2 (NetCDF).
• call MR Reset Memory :: If MetReader had been initialized and used for one set of
NWP files, but later during the execution of the calling program, a subsequent set of
NWP files is needed, this subroutine can be called to free all allocated memory.
Step 1:

The space needed for storing the NWP file meta-data must be allocated.

call MR_Allocate_FullMetFileList(iw,iwf,igrid,idf,iwfiles)
This allocates the variable MR windfiles(1:MR iwindfiles).
Step 2: The calling program must now fill the list of file names MR windfiles() with each
name not exceeding 130 characters in length. For the special cases for the NCEP/NCAR
Reanalysis 1 or the NOAA-CIRES 20th Century Reanalysis (iwf=25 or 27), MetReader
expects a specific structure to the directory holding the NWP files. For these reanalysis
product, the list of files is only one string (iwfiles=1) with the ‘file’ given as the root
directory to the NWP files. For example, for the NCEP/NCAR Reanalysis 1:
iwfiles = 1
MR_windfiles(1) = ‘/data/WindFiles/NCEP’
where the files are stored as follows:
/data/WindFiles/NCEP
|-- 2016
|
|-- air.2016.nc
|
|-- hgt.2016.nc
|
|-- omega.2016.nc
|
|-- shum.2016.nc
|
|-- uwnd.2016.nc
|
‘-- vwnd.2016.nc
|-- 2017
|-- air.2017.nc
|-- hgt.2017.nc
|-- omega.2017.nc
|-- shum.2017.nc
|-- uwnd.2017.nc
‘-- vwnd.2017.nc
Similarly, for the NOAA-CIRES 20th Century Reanalysis product:
4

iwfiles = 1
MR_windfiles(1) = ‘/data/WindFiles/NOAA’
where the files are stored as follows:
/data/WindFiles/NOAA
|-- 2008
|
|-- GRIB
|
|
|-- pgrbanl_mean_2008_HGT_pres.grib
|
|
|-- pgrbanl_mean_2008_RH_pres.grib
|
|
|-- pgrbanl_mean_2008_TMP_pres.grib
|
|
|-- pgrbanl_mean_2008_UGRD_pres.grib
|
|
|-- pgrbanl_mean_2008_VGRD_pres.grib
|
|
‘-- pgrbanl_mean_2008_VVEL_pres.grib
|
|-- pgrbanl_mean_2008_HGT_pres.nc
|
|-- pgrbanl_mean_2008_RH_pres.nc
|
|-- pgrbanl_mean_2008_TMP_pres.nc
|
|-- pgrbanl_mean_2008_UGRD_pres.nc
|
|-- pgrbanl_mean_2008_VGRD_pres.nc
|
‘-- pgrbanl_mean_2008_VVEL_pres.nc
|-- 2009
| -- ...
Note that the GRIB files are in version 1 format and cannot yet be directly read by MetReader.
They must first be converted to NetCDF and placed as described above.
Step 3: Once the names of the NWP files are specified, the files must be queried to determine the scope of the available data.
call MR_Read_Met_DimVars([iyear])
The iyear argument is optional, but is expected for iwf=25 or 27 since MetReader needs to
know whether to allocate space for 365 or 366 days. Once the subroutine is called, each of
the NWP files is checked for existence, then the following public variables are set:
• All the projection parameters for the NWP grid.
• Met dim names() :: The names of the dimensions in the file in the order of: time,
pressure1, y, x, pressure2 (for Vz), pressure3 (for RH)
• Met var names() :: The names of the variables in the file according to the Table 8.1 of
Appendix 8.1:
• Met var conversion factor() :: For each of the variables, if the units is not as listed
above, then the correpsonding factor is set that converts to the expected units. For
example, if precipitation rate is given in mm/hr, then the conversion factor to the
expected units (kg/m2 s) is 1/3600 or 2.778 × 10−4 .
5

• Met var IsAvailable() :: set to .true. if the NWP file provides this variable.
• nx fullmet,ny fullmet,np fullmet :: lengths of grid for x (lon), y (lat) and p
• x fullmet sp,y fullmet sp,p fullmet sp :: values of the grid in km (degrees) and
hPa
• IsLatLon MetGrid :: .true. if the grid is specified in longitude and latitude
• IsGlobal MetGrid :: .true. if the grid is periodic in longitude. (Note: mapping
across the poles is not yet implemented).
• IsRegular MetGrid :: .true. if dx, dy (dlon, dlat) is constant
Step 4: Next, the calling program needs to define the type of grid onto which MetReader
will interpolate values. Namely, whether or not the computational grid is projectected, and
if so, which projection and associated values. This grid used by the calling program can be
independent of the grid used by the NWP files. The parameters in the list for the subroutine
below are the values needed by the libprojection.a library. Below is an example call from
Ash3d.
call MR_Set_CompProjection(IsLatLon,A3d_iprojflag,A3d_lam0,
A3d_phi0,A3d_phi1,A3d_phi2,
A3d_k0_scale,A3d_radius_earth)

&
&

If IsLatLon=.true. then all other projection parameters are ignored. Similarly, some of
the parameters are required and others not, depending on the projection used. Currently,
libprojection.a has implemented Polar stereographic (iprojflag=1), Albers Equal Area
(iprojflag=2), UTM (iprojflag=3), Lambert conformal conic (iprojflag=4), and Mercator (iprojflag=5).
Step 5: The final prepatory step is to evaluate the windfiles provided with the spatial and
temporal requirements of the calling program.
call MR_Initialize_Met_Grids(nxmax,nymax,nzmax,
&
x(1:nxmax),y(1:nymax),z(1:nzmax), &
IsPeriodic)
nxmax,nymax,nzmax are the sizes of the computational grid. x,y,z are the single-precision
grid values in km (or degrees). IsPeriodic indicates whether or not the computational grid
is periodic in x. This subroutine also determines the size of the sub-grid of the full NWP
data that is needed by the calling program.
call MR_Set_Met_Times(SimStartHour, SimDuration)
Here SimStartHour and SimDuration give the initial time (in hours since 1900 (or other base
year)) and the length of time needed in hours. This subroutine opens all the files listed in
MR windfiles() and verifies that the files provided cover the requested time span. Then a
6

list is prepared of all the time steps and files needed to fully cover the requested time with the
step index (istep=1) corresponding to the step at or just prior to SimStartHour. The hours
between time steps is saved in MR MetStep Interval() and does not need to be constant.

3.2

Reading meteorological data

When handling data from the NWP files, there are three grids that MetReader uses:
• metP :: the native grid of the NWP file clipped to span the computational needs (possible re-ordered)
• metH :: the horizontal grid of the NWP file, but with the vertical coordinate mapped
from the pressure grid of the NWP file to the altitude grid of the computational grid.
• compH :: the full x,y,z of the computational grid.
Once the computational grid is specified and the sub-grid of the NWP is determined in step
5 above, the following public work spaces are allocated.
MR_dum2d_met_int(nx_submet,ny_submet)
MR_dum2d_met(nx_submet,ny_submet)
MR_dum3d_metP(nx_submet,ny_submet,np_fullmet)
MR_dum3d2_metP(nx_submet,ny_submet,np_fullmet)
MR_dum3d_metH(nx_submet,ny_submet,nz_comp)
MR_dum2d_comp_int(nx_comp,ny_comp)
MR_dum2d_comp(nx_comp,ny_comp)
MR_dum3d_compH(nx_comp,ny_comp,nz_comp)

::
::
::
::
::
::
::
::

integer
float
float
float
float
integer
float
float

nx comp, ny comp, np comp are the number of nodes in the computational grid and nx submet,
ny submet, np submet are the number of nodes of the NWP grid that is needed to span the
required computational grid.
To read data from the meteorological files, the fundamental subroutine is
call MR_Read_3d_MetP_Variable(ivar,istep)
where ivar is the code for the variable of interests (see Table 8.1) and istep is the index
of the sequence of time steps set up based on SimStartHour and SimDuration in Step 5
above. This subroutine provides a common interface regardless of the data format (ASCII,
NetCDF, GRIB2, etc.), data structure (latitude might be top-to-bottom or bottom-to-top,
pressure might be surface-to-top or top-down, grid might be staggered, longitude might be
−180 → 180 or 0 → 360). In all cases for 3-D variables, what is returned is the public work
array MR dum3d metP. This array is consistantly ordered such that x and y (or lon and lat)
increase with index (North to South NWP grids are flipped) and with p ordered from the
surface to top (pressure is high to low).
If 3-D data is needed on the metH grid,
call MR_Read_3d_MetH_Variable(ivar,istep)
7

can be used which first populates MR dum3d metP, then interpolates onto MR dum3d metH.
For simply reading meteorological data onto the computational grid, use
call MR_Read_3d_Met_Variable_to_CompGrid(ivar,istep,[IsNext])
This subroutine reads the variable ivar from the NWP file into MR dum3d metP, then interpolates these values onto MR dum3d metH, finally interpolating onto MR dum3d compH. The
optional argument IsNext is used when velocities are used at different points in the program
and need to be saved. IsNext indicates that the velocity values MR v[x,y] metP next should
be copied to MR v[x,y] metP last.
To interpolate 3-D data onto the altitude levels of the computational grid, first the geopotential height data must be read. This could be achieved by the subroutine MR Read 3d MetP Variable
described above, but as a simulation advances, we typically need to have the geopotential
height data for the previous and the next time steps so that values can be interpolated
between steps. The subroutine
call MR_Read_HGT_arrays(istep,[reset_first_time])
is a specialized reader for ivar=1. The first time this is called, both istep and istep+1
are called, populating the two public variables MR geoH metP last and MR geoH metP next.
Subsequent calls copy MR geoH metP next to MR geoH metP last and reads the next values
from istep+1. If the optional argument reset first time is given, both istep and istep+1
are directly read.
Similar read subroutines are available for 2-D variables.
call MR_Read_2d_Met_Variable(ivar,istep)
Given a 2-D variable identified with ivar, this populates the public work array MR dum2d met,
where again, 1:nx submet,1:ny submet corresponds to the subset of nodes of the NWP file
that is needed to span the computational grid.
call MR_Read_2d_Met_Variable_to_CompGrid(ivar,istep)
can be called similar to MR Read 2d Met Variable which directly reads the variable needed
and returns the values interpolated onto the public work space MR dum2d comp.
3.2.1

Regridding meteorological data

Internal to MetReader are a variety of regridding subroutines to interpolate from the metP
grid onto metH or compH. In some circumstances, data is initially needed just on the native
NWP grid, but then derived values might be required on the full computational grid. For
example, if air viscosity is needed for a particle fall model, temperature and pressure values on
the NWP grid can be read. Then viscosities can be calculated for each of the corresponding
nodes of the NWP grid. To interpolate these values from the metP grid to the compH grid,
the subroutine
call MR_Regrid_MetP_to_CompGrid(istep)
8

can be used. This takes the variable MR dum3d metP and interpolates it onto MR dum3d compH.
Similarly,
call MR_Regrid_MetP_to_MetH(istep)
interpolates MR dum3d metP to MR dum3d metH and
call MR_Regrid_Met2d_to_Comp2d
interpolates MR dum2d met to MR dum2d comp.
3.2.2

Wind velocity vectors

In some cases, the wind velocity vectors need to be mapped from the coordinate system of
the NWP files to the computational grid. Velocity components on the computational grid are
always provided as grid-relative. For some NWP files, such as the North American Regional
Reanalysis (NARR), the NWP grid is projected, yet the wind components are provided as
Earth-relative. In other cases, if the NWP data are provided on a projected grid, but the
computational grid is either lon/lat or on a different projection, the grid-relative, projected
velocity components must be converted to that needed for the computational grid.
If the wind data are provided as grid-relative on a projected grid and something else is
needed, the subroutine
call MR_Rotate_UV_GR2ER_Met(MR_iMetStep_Now)
will read both U and V components and decompose the vector into earth-relative Easterly and
Northerly wind components with values at the metP grid nodes. These components are put in
the variables MR u ER metP and MR v ER metP. Once we have Earth-relative velocity components (either from direct read of lon/lat data, from the subrouting MR Rotate UV GR2ER Met
or fron direct read of NARR data), if the computational grid is not Earth-relative, then these
Earth-relative components can be subsequently decomposed into grid-relative components on
the computational grid with
call MR_Rotate_UV_ER2GR_Comp(MR_iMetStep_Now)
This subroutine returns the U and V components on the compH grid through the two dummy
work space variables MR dum3d compH and MR dum3d compH 2

3.3

Additional Functions

Horizontal derivatives MetReader has subroutines for calculating horizontal derivatives
of variables on the metP grid. This is used for calculating velocity gradients for diffusivity
calculations, but could be applied to any variable. The two subroutines are MR DelMetP Dx
and MR DelMetP Dy. Both read the values from MR dum3d metP and return derivative values
on MR dum3d2 metP.

9

U.S. Standard Atmosphere MetReader also has several functions for calculating values
from the U.S. Standard Atmosphere.
• MR Temp US StdAtm(zin) :: Returns a temperature in K given a height in km.
• MR Z US StdAtm(pin) :: Returns a height in km given a pressure in hPa.
• MR Pres US StdAtm(zin) :: Returns a pressure in hPa given a height in km.

4

Supported types of meteorological data

MetReader can read meteorological data in a variety of different formats.

4.1

1-D ASCII data

The simplest format for meteorological data is just a 1-D wind profile in ASCII format.
To read this type, set iw = 1. The particular format of the 1-D data can be specified by
the iwf, where 1 indicates a user-specified column of values and 2 indicates that the files
are from the global radiosonde data available from https://ruc.noaa.gov/raobs/ or from
http://weather.uwyo.edu. In both these cases, there is no NCEP grid ID associated with
the sonde points so MR iGridCode is interpreted as the number of profile points. Each point
at each time must have its own file containing the profile data. MR idataFormat is not needed
(ASCII is assumed from iw = 1). Profiles at multiple times can be included by repeating the
sequence of profile locations at the later times. All points must have profiles for all times and
files for subsequent time steps must be given in the same order. Also, all profile files must be
in the same format (projection, columns of data). For example:
iw
= 1
iwf
= 2
igrid = 3
MR_iwindfiles = 6
PADQ_2018060100.dat
PAKN_2018060100.dat
PANC_2018060100.dat
PADQ_2018060112.dat
PAKN_2018060112.dat
PANC_2018060112.dat

4.1.1

#
#
#
#
#
#
#

This must
00Z radio
00Z radio
00Z radio
12Z radio
12Z radio
12Z radio

be an
sonde
sonde
sonde
sonde
sonde
sonde

even multiple of MR_iGrid
at Kodiak, AK
at King Salmon, AK
at Anchorage, AK
at Kodiak, AK
at King Salmon, AK
at Anchorage,

User-specified profiles

User-specified profiles describe minimally, the horizontal velocity as a function of height at
a point (or points) in the domain. Beyond this constraint, the format is fairly general. The
format is as follows.
L01
L02
L03
L04

string header line
time(hr) nlev [ncol] [ivar(ncol)]
x/lon y/lat [LLflag] [projection parameters]
data

10

Ln

:
EOF

Line 1 is a header line that is ignored
Line 2 contains at least the time of the profiles and the number of lines of data to read.
Optionally, the number of columns of data can be specified followed by a sequence of integers
specifiying the variable ID’s (see Table 8.1) for the corresponding columns. If neither of these
optional arguments ncol ivar(ncol) are given, then MetReader tests for the number of
columns present. If there are 3, then the data are read in as altitude (in m), wind speed (in
m/s), and wind direction (in degrees E of N, with the convention of where the wind is coming
from). If 5 columns are present, the fourth and fifth columns correspond to pressure (in hPa)
and temperature (in ◦ C), respectively. If the optional parameters on line 2 are given with
the number of columns of data and corresponding variables, then the variables can be read
in any order, but must include some measure of height and some measure of the wind vector.
Height can include either altitude (in m), or pressure (in hPa), or both. If only one of these
two is given, the other is filled according the the U.S. Standard Atmosphere. The measure of
the wind vector can be given either in U and V, or speed and direction. If temperature is not
provided, it is calculated from the pressure or altitude using the U.S. Standard atmosphere.
Line 3 contains the coordinate of the 1-D profile. If two values are given, the coordinate
system is assumed to be that of the computational grid (either in projected or lon/lat grids).
If more that two parameters are given, then the parameters beyond 2 are interpreted to be the
list of parameters required by libprojection.a. If the LLflag is given as a third parameter
with a value of 1, then the coordinate is interpreted to be in longitude and latitude. If the
value is 0, then the coordinate system is projected with specification defined by subsequent
values on line 3.
Line 4 contains the start of nlev rows of data
Here is an example of the 3-column format.
Hanford
2
5
-120.0
0
5000
10000
15000
20000

46.20
10.000
10.000
10.000
10.000
10.000

#wind time, number of levels
#Longitude, latitude
90.00
90.00
90.00
90.00
90.00

Here is an example of a user-specified number of columns with data on a projected grid.
Hanford
0
5
5 1 2 3 0 5 #wind time, number of levels, nvar ivars(1:nvar)
-2062.26 2606.69 0 4 265.0 25.0 25.0 25.0 6371.229 # (-120.0
46.20) in LCC grid 212 coords
0
-10.000
0.00 1000.0 10.0
5000
-10.000
0.00 560.0 -5.5
10000
-10.000
0.00 262.0 -47.3
15000
-10.000
0.00 126.0 -58.1
20000
-10.000
0.00
58.0 -54.9

11

4.1.2

1-D radiosonde profiles (single or multiple times)

Instead of user-specified profiles, MetReader can also read radiosonde data. Both the global
archive as well as the 00Z and 12Z radiosonde data are available from the NOAA Earth System
Research Laboratory Rapid Update Cycle Radiosonde Database (https://ruc.noaa.gov/raobs/).
These data are also archived at the University of Wyoming
(http://weather.uwyo.edu/upperair/sounding.html). To use data in this format, set iwf
= 2. From both these sites, radiosonde data are availalbe in a variety of formats. The default
format for the UW site is ”Text: List“
72694 SLE Salem Observations at 00Z 20 Jun 2018
----------------------------------------------------------------------------PRES
HGHT
TEMP
DWPT
RELH
MIXR
DRCT
SKNT
THTA
THTE
THTV
hPa
m
C
C
%
g/kg
deg
knot
K
K
K
----------------------------------------------------------------------------1007.0
61
30.6
8.6
25
7.01
345
7 303.1 324.5 304.4
1002.0
110
29.4
9.4
29
7.44
349
8 302.4 324.9 303.7
1000.0
129
29.2
9.2
29
7.35
350
8 302.4 324.6 303.7
980.2
305
27.5
8.5
30
7.17
355
9 302.4 324.1 303.7
946.7
610
24.6
7.4
33
6.85
0
7 302.4 323.2 303.7
925.0
814
22.6
6.6
36
6.65
350
6 302.4 322.6 303.6
914.4
914
21.7
5.7
35
6.33
345
7 302.5 321.8 303.7
908.0
975
21.2
5.2
35
6.14
352
7 302.6 321.3 303.7
:
:
:
13.3 29602 -39.7 -76.7
1
0.08
66
18 802.1 803.1 802.2
11.7 30480 -39.0 -76.4
1
0.10
90
30 834.6 835.8 834.6
10.2 31394 -38.2 -76.2
1
0.12
80
19 869.7 871.2 869.8
10.0 31557 -38.1 -76.1
1
0.12
876.2 877.8 876.2
Station information and sounding indices
Station identifier:
Station number:
Observation time:
Station latitude:
Station longitude:
Station elevation:
Showalter index:

SLE
72694
180620/0000
44.91
-123.00
61.0
6.44

:
:
:

This file contains many pressure levels, but the radiosonde standard include a limited set of
”required“ pressure levels (1000, 925, 850, 700, 500, 400, 300, 250, 200, 150, and 100 mbar; and
supplementally 70, 50, 30, 20, 10 if the probe reaches those heights.). When MetReader reads
a file of this format, only these mandatory pressure levels are read. Only the pressure, height,
12

temperature, wind direction and wind speed are read. After the columnar data are read,
the Station number is read. From this number (72694 in the above example), the station
longitude, latitude and elevation are automatically populated from internally stored station
metadata available from https://ruc.noaa.gov/raobs/General Information.html. The
station list is truncated to just what is currently operational and to just current coordinates
(some stations have been moved or deactivated). Next the Observation time is read.
An alternative format is the FAA604 WMO/GTS format from https://ruc.noaa.gov/raobs/
or the nearly identical ”Text:Raw“ format from the University of Wyoming.
TTAA
17466
24033
88188
TTBB
55762
05764
99509
34346
44231
52777
88110
PPBB
16003
93046
TTCC
45783

70001
03511
25075
54573
70008
10261
33566
09378
77323
49578
22160
60177
70008
12508
23537
70002
08022

72694
70163
49164
25052
72694
66693
06368
11494
35738
55220
54379
99106
72694
91246
24524
72694
88999

99007
04859
24541
77999
00007
04259
44551
10782
88302
51375
33153
59977
90012
12505
25049
70883
77999

30672
09008
20220
31313
30672
77655
07765
22468
39743
66194
54180
11104
34507
12011
940//
60377
31313

34507
50582
52974
58208
11002
00456
55547
14374
99278
53373
44143
60976
35509
20008
25053
11004
58208

00129
10178
25050
82346
29470
88615
07762
33440
44357
77188
56979
22102
36007
9179/
950//
50095
82346

29270
20015
15405
51515
22908
02757
66536
16981
11261
54573
55134
59977
90346
19506
26022
57778

35008
40750
55180
10164
21266
99592
08563
44381
47757
88175
56379
31313
34507
19015

92814
22974
26035
00006
33890
05350
77526
25773
22245
54774
66129
58208
02009
92025

22666
23023
10660
10194
20469
11580
08166
55346
49568
99172
57578
82346
03008
21516

35006
30953
60376
00508
44814
05756
88518
31962
33240
53376
77120
41414
90789
23018

85542
39945
23011
09506
15067
22573
08766
66330
49977
11170
57778
12761
07002
23523

11020 30421 52181 07020 20686

This format contains nearly the same information as the previous example, but requires
a bit of translation. Appendix F of
https://www.ofcm.gov/publications/fmh/FMH3/00-entire-FMH3.pdf gives the full specification. If the string ”TTAA“ is found in the ASCII file, this format is attemped first,
otherwise the ”Text:List” is assumed. This WMO/GTS format is intended for the Rapid
Update Cycle data and does not contain the year or month (only the day-of-month and
hour) of the data. If this format is detected, the year and month of the at execution time is
assumed unless otherwise specified by the calling program.

4.2

Network of 1-D radiosonde profiles

In most of the world, the radiosonde launch sites are too dispers to form a meaningful network
across which we can interpolate values. The radiosonde data is most useful for the regions
of interest proximal to launch sites. Currently, the use of multiple sonde locations is not
implemented, but simple interpolation using a small number of sonde points is planned for
future versions of this library.

4.3

3-D forecast or reanalysis data

MetReader’s preferred format for 3-D forecast and reanalysis files is NetCDF. Many products are available directly in NetCDF. format such as NCEP/NCAR Reanalysis 1 or NASA
13

GEOS-5. These products generally require NetCDF version 4. Most of the NCEP forecast
products are provided in GRIB2 format. To convert these forecast products to NetCDF format, MetReader relies on the NetCDF. java package
(https://www.unidata.ucar.edu/software/thredds/current/netcdf-java/). The conversion script in the autorun scripts folder are linked to netcdfAll-4.5 however any recent
version should work. Older versions create NetCDF files with different variable names.
Many of the forecast and reanalysis products are built in to MetReader where the grid
geometry, variable list, and pressure levels are preset. These include all the iwf numbers
listed in section 3.1. If the products change such that the pressure levels differ or if variable
names change, then the source code will need to be modified to account for the changes.
Alternatively, a template file could be used as described in section 5 below.
MetReader can also read GRIB2 files directly for certain forecast products, including
the NAM 196 grid over HI (iwf=11), the NAM 91 grid over AK (iwf=13) and the GFS
0.25 ◦ and 0.5 ◦ products (iwf=22,20). To read these GRIB2 files, an index file containing
the locations of all the records must be created. This index file can be created by the
utility gen GRIB2 index, or if the file does not exist at run-time, can be generated through
the subroutine call MR Set Gen Index GRIB(filename). In practice, if windfiles will be used
more than a few times, it is generally worthwhile to convert them to NetCDF prior to usage by
MetReader. The current implementation of the GRIB2 reader will read each of the required
GRIB2 records into memory, decompress the full gridded data, then extract the needed subgrid; whereas the NetCDF interface allows a more natural direct access to sub-grids. For
high resolution, global grids where only a small sub-grid is needed, the impact of reading and
uncompressing full grids will be noticable.

5

Custom meteorological file specification

As an alternative to using a particular forecast or reanalysis product with hard-coded file
structure, a template file can be used the allows a custom specification of a NetCDF file.
The custom template is indicated by iwf=0 and setting MR iwf template to the name of the
template file. The template file has the following format.
Line 1: The line of projection parameters as expected by libprojection.a. e.g.
Polar-stereographic Grid 91
0 1 -150.0 90.0 0.933 6371.229
Polar-stereographic Grid 216 0 1 -135.0 90.0 0.933 6371.229
Mercator
Grid 196 0 5 198.475 20.0 0.933 6371.229
Lambert Conformal Grid 212 0 4 265.0 25.0 25.0 25.0 6371.229
Lambert Conformal Grid 221 0 4 -107.0 50.0 50.0 50.0 6371.229
Line 2: StepInterval
[T/F] :: time interval in hours, and flag indicating whether or
not to use leap years (Assumed T if not provided)
Line 3: ndims nvars :: number of dimensions and variable that will be listed
Line 4-: list of dimensions where each row specifies the information about the dimension.
For example
d
d

1
2

1.6667e-2 time
100.0 lev

hours since
Pa

14

In this example, the d signifies that the row describes a dimension, 1 is the dimension number,
1.6667e-2 is a scaling factor, and time is the name of the dimension. The dimensions should
be listed in the following order: time, pressure used for primary state variables (velocity,
temperature), y (or longitude), x (or latitude), pressure used for vertical velocities, and
pressure used for moisture variables. Additional dimensions can be listed to support other
specific variables. The scaling factor is the factor needed to convert the dimension from the
units provided to the units required. In this example, the time values are supplied in minutes,
and must be multiplied by 1.6667e-2 to be in the expected units of hours. Similarly, pressure
is supplied in hPa but is expected in Pa.
Line 4+ndims- : list of variables where each row specifies the information about the
variable.
v
v
v
v
v
v
v

4
4
4
4
4
4
4

2
2
2
5
2
6
6

1
2
3
4
5
30
31

1.0
1.0
1.0
1.0
1.0
1.0
1.0

HGT
UGRD
VGRD
VVEL
TMP
RH
SPFH

H
U
V
OMEGA
T
RH
SH

gpm
m/s
m/s
Pa/s
K
%
kg/kg

In this example, the first character, v, signifies that the row describes a variable. The next
integer is the dimensionality of the variable (3 or 4). It is assumed that the variable is a
function of x, y, and t, but if also a function of pressure, the vertical dimension needs to be
specified. The next integer indicated which of the vertical dimensions listed earlier in the
file are used for this variable. The fourth item on the line (third integer) is the variable ID
according to Table 8.1. Next is the scaling factor to convert the provided values to the units
expected for the variable. The next two fields are the WMO variable name and the variable
name given in the NetCDF file.
There are several limitations of the template for the custom NWP reader. Firstly, only the
NetCDF reader is currently implemented. Secondly, currently all variables are assumed to be
transient; so land-use or topography cannot be read with this scheme. Variables that cannot
be simply scaled to the expected units cannot be described in this template. For example,
WRF files (iwf=50) uses a staggered grid with pressure and geopotential given both as a base
value plus a perturbation. Lastly, to determine the start time of the data, a reference time
must be read. First the time variable is checked for the GRIB orgReferenceTime attribute.
If this is not found, then the variable reftime is checked, if it exists.
Several examples of these template files used with NAM and GFS forecast products are
shown in Apendix 8.3.

6

Additional tools/Examples

In the tools folder, three programs are included the illustrate the use of the library.

15

6.1

MetCheck

This utility is used for checking the validity of the NWP files. In some cases, the downloading
of files might be interupted or the files on the NCEP server might be incomplete or corrupt.
This utility opens each of the files and reads the full grid for the variables: geopotential
height, Vx, Vy, Vz, and temperature. If any values are outside of expected ranges, then the
program stops returning a non-zero stop-code (stop 1). Usage:
MetCheck iwf idf filename [year]

6.2

MetSonde

This utility is used for probing the NWP files and returing the temperature as a function of
height. Usage:
MetSonde lon lat YYYY MM DD HH [WIND_ROOT]
The program assumes that the GFS and NCEP files are placed in the default directory, or
at least in default subdirectories off of WIND ROOT. Values are interpolated onto the requested
point and time and are writen to a file (GFS prof.dat) in the current working directory. This
3-column file contains the height (in km), pressure (in Pa) and temperature (in ◦ C).

6.3

MetTraj

This utility takes a similar argument list as MetSonde, but instead of probing a single point
and time, this utility calculates trajectories within either a GFS forecast package or the NCEP
reanalysis files. This utility must be compiled with either a -DFORWARD or -DBACKWARD preprocessor flag to generate separate executables for forward or backward trajectories. The
location of the windfiles is assumed to be the default for GFS and NCEP. For forward trajectories, forecast package beginning most closely prior to the requested start time is used
unless the start time is greater than two weeks from present. If so, the NCEP files are used.
For the backward trajectories, the forecast package chosen is that which can accommodate
the default 24-hours of backward integration.
For each of the trajectory calculations, files are writen to the current working directory
with the longitude and latitude of the trajectory in 1-hour increments at various elevations.
The default elevations are 5000, 10000, 20000, 30000, 40000, and 50000 ft. Files for forward
trajectories are named ftraj[1-6].dat while the backward trajectories are btraj[1-6].dat.
Optionally, the length of time to integrate and a user-specified list of output elevations
can be given. Elevations are given on the command line must be in km. Usage:
MetTraj_F lon lat YYYY MM DD HH [FC_hours nlev lev1 lev2 ...]

7

Windfile managment scripts

Scripts used to manage GFS and NCEP Reanalysis files are provided in the folder autorun scripts.
The script autorun gfs0.5deg 00 (and the dependent scripts get gfs0.5deg.sh and
convert gfs0.5deg.sh) is used for downloading and converting the 0.5◦ GFS files from
NCEP. This script is intended to be run from a cron job and take as a parameter, the hour of
the forecast package. For example autorun gfs0.5deg.sh 0 will download for 00Z for the
16

current date. These scripts use a default root download directory of /data/WindFiles, but
this can be modified within the scripts. The GFS files will be downloaded to
/data/WindFiles/gfs/gfs.YYYYMMDDHH where HH is the forecast hour (00, 06, 12, or 18).
The forecast files from hours 0-99 are downloaded then converted using netcdf-java 4.5. The
path this package is set to /ncj/netcdfAll-4.5.jar but can be modified in convert gfs0.5deg.sh.
Similarly, the script get NCEP 50YearReanalysis.sh manages the downloading of the
NCEP reanalysis files. These are placed in /data/WindFiles/NCEP/YYYY/
These scripts are intended to be run as cron jobs. The following line can be added to the
crontab to download the files once they are available.
01 22 * * *
/opt/USGS/Ash3d/bin/autorun_scripts/autorun_gfs0.5deg.sh 0 > gfs00_log 2>&1
01 11 * * *
/opt/USGS/Ash3d/bin/autorun_scripts/autorun_gfs0.5deg.sh 12 > gfs12_log 2>&1
01 01 * * Sun /opt/USGS/Ash3d/bin/autorun_scripts/autorun_NCEP_50YearReanalysis.sh > NCEP_50yr_log

Also included in autorun scripts is a simple stand-alone script (grib2nc.sh) for converting GRIB2 files to NetCDF using netcdf-java.

17

2>&1

8
8.1

Appendix
Variable codes
Table 1: Variable codes
Variable type

3d Mechanical

Surface

Atmospheric Structure

Moisture

Precipitation

ID
1
2
3
4
5
6
7
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
30
31
32
33
40
41
42
43
44
45
46
47

Name
Geopotential Height
Vx
Vy
Vz
Temperature
Wind speed
Wind direction
Planetary Boundary Layer Height
U @ 10m
V @ 10m
Friction velocity
Displacement Height
Snow cover
Soil moisture
Surface Roughness
Wind gust speed
surface temperature
pressure at lower cloud base
pressure at lower cloud top
temperature at lower cloud top
Total Cloud cover
Cloud cover (low)
Cloud cover (convective)
Rel. Hum
QV (specific humidity)
QL (liquid)
QI (ice)
Categorical rain
Categorical snow
Categorical frozen rain
Categorical ice
Precipitation rate large-scale (liquid)
Precipitation rate convective (liquid)
Precipitation rate large-scale (ice)
Precipitation rate convective (ice)

18

dimensions
gmp or m2 /s2
m/s
m/s
Pa/s
K
m/s
deg East of North
m
m/s
m/s
m/s
m
%
kg/m2
m
m/s
K
Pa
Pa
K
%
%
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg/m2 s
kg/m2 s
kg/m2 s
kg/m2 s

8.2

NWP product ID (iwf)

Several NWP product (both reanalysis and forecast) are recognized and do not need template
files. These are listed in the table below by the format code. iwf=1,2 are ASCII files.
iwf=3-19 are reserved for products with projected grids. iwf=20-49 are reserved for global
(lon/lat) grids. iwf=50 is for NetCDF output from Weather Research and Forecasting (WRF)
simulations.

iwf
0
1
2
3
4
5
6
7
8
10
11
12
13
20
21
22
23
24
25
27
28
32
33
40
41
50

Table 2: NWP product ID
Product
NCEP Grid
Custom format based on template
ASCII profile
Radiosonde data
North American Regional Reanalysis NARR-A
221
North American Regional Reanalysis NARR-A+B 221
NAM Regional Alaska
216
NAM N. Hemisphere
104
NAM Regional CONUS
212
NAM Regional CONUS
218
NAM Regional Alaska
242
NAM Regional Hawaii
196
NAM Regional Alaska
198
NAM Regional Alaska
91
GFS
4
GFS
3
GFS
193
NCEP-DOE Reanalysis 2
2
NASA-MERRA-2 Reanalysis
None
NCEP/NCAR Reanalysis 1
2
NOAA-CIRES 20th Century Reanalysis
2
ECMWF ERA-Interim Reanalysis
170
Air Force Weather Agency subcenter = 0
None
CCSM3.0 Community Atmosphere Model
None
NASA GEOS-5 Cp
None
NASA GEOS-5 Np
None
WRF - output
None

19

resolution

32 km
32 km
45 km
90 km
40 km
12 km
11.25 km
2.5 km
5.953 km
2.976 km
0.5 ◦
1.0 ◦
0.25 ◦
2.5 ◦
0.625 × 0.5◦
2.5 ◦
2.5◦
∼ 0.7◦ -Gaussian
0.25◦
3.75 × 3.7◦
0.625 × 0.5◦
0.3125 × 0.25◦

8.3

Example Template files

NCEP−Grids

Figure 1: Outlines of North America Mesoscale (NAM) and Global Forecast System (GFS)
models from NCEP that are compatible with MetReader template files.

20

8.4

NAM 221 Regional N.America (32.5 km)

nam.t00z.awip3200.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/

Figure 2: NAM 221, Regional N. America 32.5 km Lambert Conformal Conical

21

n221_template.txt
0 4 -107.0 50.0 50.0 50.0 6371.229
3.0
9 29
d
1
1.0 time
d
2
1.0 isobaric1
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric1
d
6
1.0 isobaric1
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0 CPRAT
Convective_Precipitation_Rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

22

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2.s-1
kg.m-2
kg.m-2
kg.m-2

8.5

NAM 216 AK (45.0 km); NAM 242 AK (11.25 km)

nam.t00z.awipak00.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/
http://motherlode.ucar.edu/native/conduit/data/nccf/com/nam/prod/nam.YYYYMMDD/

Figure 3: NAM 216, AK 45.0 km Polar Stereographic

23

n216_template.txt
0 1 -135.0 90.0 0.933 6371.229
3.0
9 27
d
1
1.0 time
d
2
1.0 isobaric1
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric1
d
6
1.0 isobaric1
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0 CPRAT
Convective_Precipitation_Rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

24

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2.s-1
kg.m-2
kg.m-2
kg.m-2

Grid 242 uses the same projection and domain as Grid 216, but with 11.25 km grid
spacing.
nam.t00z.awak3d00.grb2.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/
n242_template.txt
0 1 -135.0 90.0 0.933 6371.229
3.0
9 27
d
1
1.0 time
d
2
1.0 isobaric2
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric
d
6
1.0 isobaric2
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric6
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0 CPRAT
Convective_Precipitation_Rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

25

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2.s-1
kg.m-2
kg.m-2
kg.m-2

8.6

NAM 91 AK (2.95 km); NAM 198 AK (5.9 km)

nam.t00z.alaskanest.hiresf00.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/

Figure 4: NAM 91, AK 2.95 km Polar Stereographic (previously NAM 198, AK 5.9 km)

26

n091_template.txt
0 1 -150.0 90.0 0.933 6371.229
1.0
9 29
d
1
1.0 time
d
2
1.0 isobaric2
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric2
d
6
1.0 isobaric2
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric3
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0 CPRAT
Convective_Precipitation_Rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

27

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2.s-1
kg.m-2
kg.m-2
kg.m-2

8.7

NAM 243 Eastern N. Pac./HI (0.40 ◦ )

nam.t00z.awiphi00.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/

Figure 5: NAM 243, Eastern N. Pac./HI 0.4 ◦

28

n243_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
9 24
d
1
1.0 time
d
2
1.0 isobaric2
d
3
1.0 lat
d
4
1.0 lon
d
5
1.0 isobaric1
d
6
1.0 isobaric2
d
7
1.0 height_above_ground
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

29

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m/s
m/s
m.s-1
m
Pa
Pa
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2
kg.m-2
kg.m-2

8.8

NAM 182 HI (0.108 ◦ )

nam.t00z.afwahi00.grb2.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/

Figure 6: NAM 182, HI 0.108 ◦

30

n182_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
8 22
d
1
1.0 time1
d
2
1.0 isobaric
d
3
1.0 lat
d
4
1.0 lon
d
5
1.0 isobaric
d
6
1.0 isobaric
d
7
1.0 height_above_ground2
d
8
1.0 depth_below_surface_layer
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation

31

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2
kg.m-2

8.9

NAM 196 HI (2.5 km)

nam.t00z.hawaiinest.hiresf00.tm0
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/

Figure 7: NAM 196, AK 2.5 km Mercator

32

n196_template.txt
0 5 198.475 20.0 6371.229
1.0
9 27
d
1
1.0 time
d
2
1.0 isobaric2
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric2
d
6
1.0 isobaric2
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

33

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2
kg.m-2

8.10

NAM 211/212/218/227 CONUS

Figure 8: NAM 211/212/218/227 CONUS Lambert Conformal Conical (dots correspond
to the 81.3 km 211 grid)

34

Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/
NAM 211 CONUS (81.3 km) :: nam.t00z.awp21100.tm00
n211_template.txt
0 4 265.0 25.0 25.0 25.0 6371.229
6.0
9 18
d
1
1.0 time
d
2
1.0 isobaric
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric
d
6
1.0 isobaric
d
7
1.0 height_above_ground1
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m/s
Pa
Pa
%
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2
kg.m-2

NAM 212 CONUS (40.6 km) :: nam.t00z.awip3d00.tm00
n212_template.txt
0 4 265.0 25.0 25.0 25.0 6371.229
3.0
9 29
d
1
1.0 time
d
2
1.0 isobaric1
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric1
d
6
1.0 isobaric1
d
7
1.0 height_above_ground2
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric1
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0 CPRAT
Convective_Precipitation_Rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

35

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2.s-1
kg.m-2
kg.m-2
kg.m-2

NAM 218 CONUS (12.2 km) :: nam.t00z.awphys00.grb2.tm00
n218_template.txt
0 4 265.0 25.0 25.0 25.0 6371.229
1.0
9 21
d
1
1.0 time
d
2
1.0 isobaric1
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric1
d
6
1.0 isobaric
d
7
1.0 height_above_ground4
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
%
%
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2
kg.m-2

NAM 227 CONUS (5.1 km) :: nam.t00z.conusnest.hiresf00.tm00
n227_template.txt
0 4 265.0 25.0 25.0 25.0 6371.229
1.0
9 27
d
1
1.0 time
d
2
1.0 isobaric2
d
3
1.0 y
d
4
1.0 x
d
5
1.0 isobaric2
d
6
1.0 isobaric2
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 17
1.0
SFCR
Surface_roughness_surface
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 3 0 20
1.0
PRES
Pressure_cloud_base
v 3 0 21
1.0
PRES
Pressure_cloud_tops
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 44
1.0 PRATE
Precipitation_rate_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 47
1.0 NCPCP
Large-scale_precipitation_non-convective_surface_0_Hour_Accumulation

36

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
m
m/s
Pa
Pa
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2.s-1
kg.m-2
kg.m-2

8.11

NAM 181 Caribbean (0.108 ◦ )

nam.t00z.afwaca00.grb2.tm00
Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/nam.YYYYMDD/

Figure 9: NAM 181, Caribbean 0.108 ◦

37

n181_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
8 22
d
1
1.0 time1
d
2
1.0 isobaric
d
3
1.0 lat
d
4
1.0 lon
d
5
1.0 isobaric
d
6
1.0 isobaric
d
7
1.0 height_above_ground2
d
8
1.0 depth_below_surface_layer
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 13
1.0 FRICV
Frictional_Velocity_surface
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 23
1.0
TCDC
Total_cloud_cover_entire_atmosphere
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 6 31
1.0
SPFH
Specific_humidity_isobaric
v 4 9 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric
v 4 9 33
1.0
SNMR
Snow_mixing_ratio_isobaric
v 3 0 40
1.0 CRAIN
Categorical_Rain_surface
v 3 0 41
1.0 CSNOW
Categorical_Snow_surface
v 3 0 42
1.0 CFRZR
Categorical_Freezing_Rain_surface
v 3 0 43
1.0 CICEP
Categorical_Ice_Pellets_surface
v 3 0 45
1.0
APCP
Total_precipitation_surface_0_Hour_Accumulation
v 3 0 46
1.0 ACPCP
Convective_precipitation_surface_0_Hour_Accumulation

38

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m.s-1
m
Fraction
%
%
kg/kg
kg/kg
kg/kg
0 or 1
0 or 1
0 or 1
0 or 1
kg.m-2
kg.m-2

8.12

GFS 3/4/193

Figure 10: GFS 3,4,193, (dots correspond to the 1.0 ◦ NAM 3 grid)

39

Available from:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.YYYYMDD/
GFS NCEP Grid 3 (1.0 ◦ ) :: gfs.t00z.pgrb2.1p00.f000.nc
n003_template.txt
GFS NCEP grid 4 (0.5 ◦ ) :: n004_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
9 13
d
1
1.0 time
d
2
1.0 isobaric3
d
3
1.0 lat
d
4
1.0 lon
d
5
1.0 isobaric2
d
6
1.0 isobaric3
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 5 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m
Fraction
m/s
%
kg/kg

GFS NCEP grid 193 (0.25 ◦ ) :: n193_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
9 13
d
1
1.0 time
d
2
1.0 isobaric3
d
3
1.0 lat
d
4
1.0 lon
d
5
1.0 isobaric2
d
6
1.0 isobaric3
d
7
1.0 height_above_ground3
d
8
1.0 depth_below_surface_layer
d
9
1.0 isobaric4
v 4 2 1
1.0
HGT
Geopotential_height_isobaric
v 4 2 2
1.0
UGRD
u-component_of_wind_isobaric
v 4 2 3
1.0
VGRD
v-component_of_wind_isobaric
v 4 5 4
1.0
VVEL
Vertical_velocity_pressure_isobaric
v 4 2 5
1.0
TMP
Temperature_isobaric
v 3 0 10
1.0
HPBL
Planetary_Boundary_Layer_Height_surface
v 4 7 11
1.0
UGRD
u-component_of_wind_height_above_ground
v 4 7 12
1.0
VGRD
v-component_of_wind_height_above_ground
v 3 0 15
1.0
SNOD
Snow_depth_surface
v 4 2 16
1.0 SOILW
Volumetric_Soil_Moisture_Content_depth_below_surface_layer
v 3 0 18
1.0
GUST
Wind_speed_gust_surface
v 4 6 30
1.0
RH
Relative_humidity_isobaric
v 4 5 32
1.0 CLWMR
Cloud_mixing_ratio_isobaric

40

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
m
m
Pa
gpm
m/s
m/s
Pa/s
K
m
m/s
m/s
m
Fraction
m/s
%
kg/kg

8.13

NASA GEOS-5

Figure 11: NASA GEOS-5, 0.625/0.5 ◦

41

Available from:
ftp://gmao_ops@ftp.nccs.nasa.gov/fp/forecast//
NASA GEOS-5 Cp (0.625/0.5 ◦ ) ::
GEOS.fp.fcst.inst3_3d_asm_Cp.YYYYMMDD_00+YYYYMMDD_mmmm.V01.nc4
nGCp_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
6 7
d
1 1.6667e-2 time
d
2
100.0 lev
d
3
1.0 lat
d
4
1.0 lon
d
5
100.0 lev
d
6
100.0 lev
v 4 2 1
1.0
HGT
H
v 4 2 2
1.0
UGRD
U
v 4 2 3
1.0
VGRD
V
v 4 5 4
1.0
VVEL
OMEGA
v 4 2 5
1.0
TMP
T
v 4 6 30
1.0
RH
RH
v 4 6 31
1.0
SPFH
SH

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
gpm
m/s
m/s
Pa/s
K
%
kg/kg

NASA GEOS-5 Np (0.25/0.3125 ◦ ) ::
GEOS.fp.fcst.inst3_3d_asm_Np.YYYYMMDD_00+YYYYMMDD_mmmm.V01.nc4
nGNp_template.txt
1 1 -150.0 90.0 0.933 6371.229
3.0
6 7
d
1 1.6667e-2 time
d
2
100.0 lev
d
3
1.0 lat
d
4
1.0 lon
d
5
100.0 lev
d
6
100.0 lev
v 4 2 1
1.0
HGT
H
v 4 2 2
1.0
UGRD
U
v 4 2 3
1.0
VGRD
V
v 4 5 4
1.0
VVEL
OMEGA
v 4 2 5
1.0
TMP
T
v 4 6 30
1.0
RH
RH
v 4 6 31
1.0
SPFH
SH

Projection params line
Time interval
ndims, nvars
hours since
Pa
km or deg
km or deg
Pa
Pa
gpm
m/s
m/s
Pa/s
K
%
kg/kg

42



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