UEMS don't use hourly GFS data

Questions and other topics related to UEMS 18.
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meteo60
Posts: 117
Joined: Tue Apr 17, 2012 4:50 pm

UEMS don't use hourly GFS data

Post by meteo60 » Wed May 30, 2018 12:34 pm

Hi,
I updated UEMS to 18.4.2. Since I have this message in the log:
The 0.25 degree GFS dataset is 3-hourly beyond hour 84. Since your
simulation length is 93 hours, the default BC update frequency is to
3-hourly.
Before the update, UEMS used hourly data beyond hour 84.
How to force to use hourly data?

meteo60
Posts: 117
Joined: Tue Apr 17, 2012 4:50 pm

Re: UEMS don't use hourly GFS data

Post by meteo60 » Tue Oct 22, 2019 10:17 am

Simple:
Comment these lines in strc/Uprep/Pconf.pm:

Code: Select all

#----------------------------------------------------------------------------------
        #  This is a hack that may need to be replaced someday.  In 2018 th GFS 0.25
        #  degree dataset is hourly through hour 84 and then 3-hourly through hour 240.
        #  If the length of the forecast is greater than 84 hours, change the freqfh
        #  value from 1- to 3-hourly.
        #----------------------------------------------------------------------------------
        #
        # if ($dset =~ /gfsp25/i and $gribinfo{freqfh} == 1 and $Uprep{parms}{length} > 84) {
            # my $mesg = "The 0.25 degree GFS dataset is 3-hourly beyond hour 84. Since your ".
                       # "simulation length is $Uprep{parms}{length} hours, the default BC update ".
                       # "frequency is to 3-hourly.";
            # &Ecomm::PrintMessage(6,6+$Uprep{arf},88,1,2,'Just letting you know:',$mesg);

            # $gribinfo{freqfh} = 3;
        # } 

pattim
Posts: 199
Joined: Sun Jun 24, 2012 8:42 pm
Location: Los Angeles, CA, USA

Re: UEMS don't use hourly GFS data (FIX)

Post by pattim » Fri Feb 28, 2020 4:42 pm

This is my fix: I've noticed at least one other server has the change from some fine-grained hourly datasets to a coarser-grained dataset past some amount of hours. So you have to force coarse-grained from the beginning, like so:
--cycle :::3
...this forces 3 hourly BC updates throughout the simulation. The ":" characters are placeholders for other parameters which I'm ignoring in this example.

From the Userguide
:
Here is some more “--cycle” fun:

% ems_prep --dset gfsp25 --cycle 12:06:30:06

Translation: The above request is similar to the first example except that the cycle time (12
UTC), initialization forecast hour (06), final forecast hour (30), and boundary condition update
frequency (06 hourly)
are included as arguments to “--cycle” ...

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