[Met_help] [rt.rap.ucar.edu #79901] History for question about file-format and wind speed calculation in MET
John Halley Gotway via RT
met_help at ucar.edu
Thu Apr 6 08:56:41 MDT 2017
----------------------------------------------------------------
Initial Request
----------------------------------------------------------------
Hello,
I just start to use MET. Here I have some questions when using Grid-stat
tool to do the verification for wind speed.
My observation is RTMA data, regridded into GRIB2 format using wgrib2. The
forecast data are from WRF model forecast, I converted them into GRIB1
format using UPP. And observation and forecast data share common grid now.
For my understanding, MET can read GRIB1&2 easily so I don't have to
convert wrfout from GRIB1 to GRIB2. Is it right?
RTMA has wind speed data. However, wrfout has U10, V10 separately. I think
I need to calculate sqrt(u^2+v^2) to prepare data for Grid-stat. Does MET
has tool to do so?
Currently the method I know is using NCL to read the original wrfout*.nc
and calculate wind speed , write out into a new .nc file. Then convert the
new .nc file to GRIB1 format using UPP. I wounder if MET has a more
efficient tool? Do you have any suggestions?
Also, I checked the parameter table and believe the wind speed in RTMA
should be named as "WIND" in the config_file, obs dictionary. should I use
the same name for WRF data in fcst dictionary?
Thank you very much!
--
Ying Song, PhD, Post Doctoral Fellow
Department of Earth and Atmospheric Sciences
Saint Louis University
ysong4 at slu.edu
----------------------------------------------------------------
Complete Ticket History
----------------------------------------------------------------
Subject: question about file-format and wind speed calculation in MET
From: John Halley Gotway
Time: Mon Mar 20 15:31:26 2017
Ying,
I see that you'd like to compute and verify wind speed using MET.
Good
news, MET already includes logic for deriving wind speed on the fly.
The
GRIB abbreviation for wind speed is WIND. If you request WIND from a
GRIB1
or GRIB2 file, MET first checks to see if it already exists in your
file.
If so, it'll use it as is. If not, it'll search for the corresponding
U
and V records and derive wind speed for you on the fly.
Let's suppose your RTMA file is named rtma.grb2 and your UPP file is
named
wrf.grb, please try running the following commands to plot wind speed:
met-5.2/bin/plot_data_plane wrf.grb wrf_wind.ps 'name"WIND";
level="Z10";' -v 3
met-5.2/bin/plot_data_plane rtma.grb2 rtma_wind.ps 'name"WIND";
level="Z10";' -v 3
In the first call, you should see this sort of log message:
DEBUG 3: MetGrib1DataFile::data_plane_array() -> Attempt to derive
winds
from U and V components.
In the second one, you won't since wind speed already exists in the
RTMA
file.
Hope that helps clarify.
Thanks,
John Halley Gotway
met_help at ucar.edu
On Mon, Mar 20, 2017 at 2:33 PM, Ying Song via RT <met_help at ucar.edu>
wrote:
>
> Mon Mar 20 14:33:24 2017: Request 79901 was acted upon.
> Transaction: Ticket created by ysong4 at slu.edu
> Queue: met_help
> Subject: question about file-format and wind speed calculation
in MET
> Owner: Nobody
> Requestors: ysong4 at slu.edu
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=79901 >
>
>
> Hello,
>
> I just start to use MET. Here I have some questions when using Grid-
stat
> tool to do the verification for wind speed.
>
> My observation is RTMA data, regridded into GRIB2 format using
wgrib2. The
> forecast data are from WRF model forecast, I converted them into
GRIB1
> format using UPP. And observation and forecast data share common
grid now.
>
> For my understanding, MET can read GRIB1&2 easily so I don't have to
> convert wrfout from GRIB1 to GRIB2. Is it right?
>
> RTMA has wind speed data. However, wrfout has U10, V10 separately. I
think
> I need to calculate sqrt(u^2+v^2) to prepare data for Grid-stat.
Does MET
> has tool to do so?
> Currently the method I know is using NCL to read the original
wrfout*.nc
> and calculate wind speed , write out into a new .nc file. Then
convert the
> new .nc file to GRIB1 format using UPP. I wounder if MET has a more
> efficient tool? Do you have any suggestions?
>
> Also, I checked the parameter table and believe the wind speed in
RTMA
> should be named as "WIND" in the config_file, obs dictionary. should
I use
> the same name for WRF data in fcst dictionary?
>
> Thank you very much!
>
> --
> Ying Song, PhD, Post Doctoral Fellow
> Department of Earth and Atmospheric Sciences
> Saint Louis University
>
> ysong4 at slu.edu
>
>
------------------------------------------------
Subject: question about file-format and wind speed calculation in MET
From: Ying Song
Time: Wed Mar 22 11:11:45 2017
Thanks for the reply! Good to know that MET contains the logic for
deriving
wind speed. I checked my wrf.grb and rtma.grb2. And I do find the log
message:
DEBUG 3: MetGrib1DataFile::data_plane_array() -> Attempt to
derive
winds from U and V components.
Since both wrf.grb and rtma.grb2 includes 12 hours' hourly wind speed
data,
I got the message like following:
WARNING: MetGrib1DataFile::data_plane() -> Found 12 matches for
VarInfo
"WIND/Z10" in GRIB file "wrf.grib". Using the first match found.
WARNING: MetGrib2DataFile::data_plane() - Multiple matching records
found
for 'WIND/Z10' - 2, 3, 6, 7, 10, 11, 13, 15, 18, 19, 22, 24, 26, 27,
30,
31, 34, 35, 38, 39, 41, 43, 46, 47 - using 2
looks like only the first hour data is plotted. How does MET handle
the
time dimension? I saw the Stat-analysis tool can aggregate the results
through time, but what if my obs.grb and wrf.grb already have time
dimension?
Thanks!
On Mon, Mar 20, 2017 at 4:31 PM, John Halley Gotway via RT <
met_help at ucar.edu> wrote:
> Ying,
>
> I see that you'd like to compute and verify wind speed using MET.
Good
> news, MET already includes logic for deriving wind speed on the fly.
The
> GRIB abbreviation for wind speed is WIND. If you request WIND from
a GRIB1
> or GRIB2 file, MET first checks to see if it already exists in your
file.
> If so, it'll use it as is. If not, it'll search for the
corresponding U
> and V records and derive wind speed for you on the fly.
>
> Let's suppose your RTMA file is named rtma.grb2 and your UPP file is
named
> wrf.grb, please try running the following commands to plot wind
speed:
>
> met-5.2/bin/plot_data_plane wrf.grb wrf_wind.ps 'name"WIND";
> level="Z10";' -v 3
> met-5.2/bin/plot_data_plane rtma.grb2 rtma_wind.ps 'name"WIND";
> level="Z10";' -v 3
>
> In the first call, you should see this sort of log message:
> DEBUG 3: MetGrib1DataFile::data_plane_array() -> Attempt to
derive
> winds
> from U and V components.
>
> In the second one, you won't since wind speed already exists in the
RTMA
> file.
>
> Hope that helps clarify.
>
> Thanks,
> John Halley Gotway
> met_help at ucar.edu
>
> On Mon, Mar 20, 2017 at 2:33 PM, Ying Song via RT
<met_help at ucar.edu>
> wrote:
>
> >
> > Mon Mar 20 14:33:24 2017: Request 79901 was acted upon.
> > Transaction: Ticket created by ysong4 at slu.edu
> > Queue: met_help
> > Subject: question about file-format and wind speed
calculation in
> MET
> > Owner: Nobody
> > Requestors: ysong4 at slu.edu
> > Status: new
> > Ticket <URL:https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__rt.rap.ucar.edu_rt_Ticket_Display.html-3Fid-3D79901&d=
> DwIDaQ&c=Pk_HpaIpE_jAoEC9PLIWoQ&r=DoGUCazxekmrzloEJ54sJA&m=
> vsXEcuUWb_xJ6xQyUWhWmcLcq10-R__zyfMM-ZmNvg8&s=_CSrXQH9_p_
> QwYf2K_mXUH5LRuQu5qN_8z2YLQ98D5w&e= >
> >
> >
> > Hello,
> >
> > I just start to use MET. Here I have some questions when using
Grid-stat
> > tool to do the verification for wind speed.
> >
> > My observation is RTMA data, regridded into GRIB2 format using
wgrib2.
> The
> > forecast data are from WRF model forecast, I converted them into
GRIB1
> > format using UPP. And observation and forecast data share common
grid
> now.
> >
> > For my understanding, MET can read GRIB1&2 easily so I don't have
to
> > convert wrfout from GRIB1 to GRIB2. Is it right?
> >
> > RTMA has wind speed data. However, wrfout has U10, V10 separately.
I
> think
> > I need to calculate sqrt(u^2+v^2) to prepare data for Grid-stat.
Does MET
> > has tool to do so?
> > Currently the method I know is using NCL to read the original
wrfout*.nc
> > and calculate wind speed , write out into a new .nc file. Then
convert
> the
> > new .nc file to GRIB1 format using UPP. I wounder if MET has a
more
> > efficient tool? Do you have any suggestions?
> >
> > Also, I checked the parameter table and believe the wind speed in
RTMA
> > should be named as "WIND" in the config_file, obs dictionary.
should I
> use
> > the same name for WRF data in fcst dictionary?
> >
> > Thank you very much!
> >
> > --
> > Ying Song, PhD, Post Doctoral Fellow
> > Department of Earth and Atmospheric Sciences
> > Saint Louis University
> >
> > ysong4 at slu.edu
> >
> >
>
>
--
Ying Song, PhD, Post Doctoral Fellow
Department of Earth and Atmospheric Sciences
Saint Louis University
ysong4 at slu.edu
------------------------------------------------
Subject: question about file-format and wind speed calculation in MET
From: John Halley Gotway
Time: Wed Mar 22 11:29:21 2017
Ying,
To be clear, it sounds like your GRIB1/2 files contain multiple output
times. This is not the typical case... usually different output times
are
stored in different files. That's fine, we just need to tell MET how
to
handle the data.
Grid-Stat is designed to be run once per output time. So you could
run
Grid-Stat multiple times, once for each output time. Or you could run
Grid-Stat once to verify multiple output times from the same file, but
your
config file will be longer.
Here's what the two options would look like:
(1) Run once per output time, listing a single "field", set the Grid-
Stat
config file like this:
fcst = {
field = [ { name="WIND"; level="Z2"; lead_time="12"; } ];
...
This would verify forecast lead time of 12 hours. Look in
met-5.2/data/config/README to see that "lead_time", "valid_time", and
"init_time" strings can all be used to specify how the data should be
filtered.
And rather then setting lead_time="12"; set lead_time="${FCST_LEAD}";
and
have the calling script define FCST_LEAD as an environment variable.
So
your script could loop through your lead times, set the environment
variable, and call Grid-Stat.
(2) Run once for all output times, listing multiple "fields", set the
Grid-Stat config file like this:
fcst = {
field = [
{ name="WIND"; level="Z2"; lead_time="00"; },
{ name="WIND"; level="Z2"; lead_time="06"; },
{ name="WIND"; level="Z2"; lead_time="12"; },
{ name="WIND"; level="Z2"; lead_time="18"; },
{ name="WIND"; level="Z2"; lead_time="24"; },
{ name="WIND"; level="Z2"; lead_time="30"; }
];
If you list 6 forecast fields, you'll need to list the 6 matching
observation fields. But for observation data, there "lead_time" will
always be zero. So in that case, you'll likely need to define the
"valid_time" instead.
So while MET *can* handle multiple output times in a single files, the
details get a lot trickier when you set up your data that way.
Thanks,
John
On Wed, Mar 22, 2017 at 11:11 AM, Ying Song via RT <met_help at ucar.edu>
wrote:
>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=79901 >
>
> Thanks for the reply! Good to know that MET contains the logic for
deriving
> wind speed. I checked my wrf.grb and rtma.grb2. And I do find the
log
> message:
> DEBUG 3: MetGrib1DataFile::data_plane_array() -> Attempt to
derive
> winds from U and V components.
>
> Since both wrf.grb and rtma.grb2 includes 12 hours' hourly wind
speed data,
> I got the message like following:
> WARNING: MetGrib1DataFile::data_plane() -> Found 12 matches for
VarInfo
> "WIND/Z10" in GRIB file "wrf.grib". Using the first match found.
> WARNING: MetGrib2DataFile::data_plane() - Multiple matching records
found
> for 'WIND/Z10' - 2, 3, 6, 7, 10, 11, 13, 15, 18, 19, 22, 24, 26, 27,
30,
> 31, 34, 35, 38, 39, 41, 43, 46, 47 - using 2
>
> looks like only the first hour data is plotted. How does MET handle
the
> time dimension? I saw the Stat-analysis tool can aggregate the
results
> through time, but what if my obs.grb and wrf.grb already have time
> dimension?
>
> Thanks!
>
> On Mon, Mar 20, 2017 at 4:31 PM, John Halley Gotway via RT <
> met_help at ucar.edu> wrote:
>
> > Ying,
> >
> > I see that you'd like to compute and verify wind speed using MET.
Good
> > news, MET already includes logic for deriving wind speed on the
fly. The
> > GRIB abbreviation for wind speed is WIND. If you request WIND
from a
> GRIB1
> > or GRIB2 file, MET first checks to see if it already exists in
your file.
> > If so, it'll use it as is. If not, it'll search for the
corresponding U
> > and V records and derive wind speed for you on the fly.
> >
> > Let's suppose your RTMA file is named rtma.grb2 and your UPP file
is
> named
> > wrf.grb, please try running the following commands to plot wind
speed:
> >
> > met-5.2/bin/plot_data_plane wrf.grb wrf_wind.ps
'name"WIND";
> > level="Z10";' -v 3
> > met-5.2/bin/plot_data_plane rtma.grb2 rtma_wind.ps 'name"WIND";
> > level="Z10";' -v 3
> >
> > In the first call, you should see this sort of log message:
> > DEBUG 3: MetGrib1DataFile::data_plane_array() -> Attempt to
derive
> > winds
> > from U and V components.
> >
> > In the second one, you won't since wind speed already exists in
the RTMA
> > file.
> >
> > Hope that helps clarify.
> >
> > Thanks,
> > John Halley Gotway
> > met_help at ucar.edu
> >
> > On Mon, Mar 20, 2017 at 2:33 PM, Ying Song via RT
<met_help at ucar.edu>
> > wrote:
> >
> > >
> > > Mon Mar 20 14:33:24 2017: Request 79901 was acted upon.
> > > Transaction: Ticket created by ysong4 at slu.edu
> > > Queue: met_help
> > > Subject: question about file-format and wind speed
calculation in
> > MET
> > > Owner: Nobody
> > > Requestors: ysong4 at slu.edu
> > > Status: new
> > > Ticket <URL:https://urldefense.proofpoint.com/v2/url?u=https-
> > 3A__rt.rap.ucar.edu_rt_Ticket_Display.html-3Fid-3D79901&d=
> > DwIDaQ&c=Pk_HpaIpE_jAoEC9PLIWoQ&r=DoGUCazxekmrzloEJ54sJA&m=
> > vsXEcuUWb_xJ6xQyUWhWmcLcq10-R__zyfMM-ZmNvg8&s=_CSrXQH9_p_
> > QwYf2K_mXUH5LRuQu5qN_8z2YLQ98D5w&e= >
> > >
> > >
> > > Hello,
> > >
> > > I just start to use MET. Here I have some questions when using
> Grid-stat
> > > tool to do the verification for wind speed.
> > >
> > > My observation is RTMA data, regridded into GRIB2 format using
wgrib2.
> > The
> > > forecast data are from WRF model forecast, I converted them into
GRIB1
> > > format using UPP. And observation and forecast data share common
grid
> > now.
> > >
> > > For my understanding, MET can read GRIB1&2 easily so I don't
have to
> > > convert wrfout from GRIB1 to GRIB2. Is it right?
> > >
> > > RTMA has wind speed data. However, wrfout has U10, V10
separately. I
> > think
> > > I need to calculate sqrt(u^2+v^2) to prepare data for Grid-stat.
Does
> MET
> > > has tool to do so?
> > > Currently the method I know is using NCL to read the original
> wrfout*.nc
> > > and calculate wind speed , write out into a new .nc file. Then
convert
> > the
> > > new .nc file to GRIB1 format using UPP. I wounder if MET has a
more
> > > efficient tool? Do you have any suggestions?
> > >
> > > Also, I checked the parameter table and believe the wind speed
in RTMA
> > > should be named as "WIND" in the config_file, obs dictionary.
should I
> > use
> > > the same name for WRF data in fcst dictionary?
> > >
> > > Thank you very much!
> > >
> > > --
> > > Ying Song, PhD, Post Doctoral Fellow
> > > Department of Earth and Atmospheric Sciences
> > > Saint Louis University
> > >
> > > ysong4 at slu.edu
> > >
> > >
> >
> >
>
>
> --
> Ying Song, PhD, Post Doctoral Fellow
> Department of Earth and Atmospheric Sciences
> Saint Louis University
>
> ysong4 at slu.edu
>
>
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