[Wrf-users] grid ratio & map factor

[HEDDE Thierry 137147]

Hi Luciano,

Ratio between GFS and WRF : yes you may take a ratio of 3 between GFS and WRF grid : for example I'm using GFS 0.25° (~25km grid) and my mother domain for WRF is 9km. There is no need to keep the same grid size between GFS and WRF.

Map factor : the map factor has nothing to do with the grid resolution, as far as I know it's the deformation of the grid due to the geographic projection of the earth sphere on a plane (Lambert for example). 

Cheers
Thierry

-----Message d'origine-----
De : Wrf-users [mailto:wrf-users-bounces at ucar.edu] De la part de wrf-users-request at ucar.edu
Envoyé : samedi 2 décembre 2017 20:00
À : wrf-users at ucar.edu
Objet : Wrf-users Digest, Vol 160, Issue 1

Send Wrf-users mailing list submissions to
	wrf-users at ucar.edu

To subscribe or unsubscribe via the World Wide Web, visit
	http://mailman.ucar.edu/mailman/listinfo/wrf-users
or, via email, send a message with subject or body 'help' to
	wrf-users-request at ucar.edu

You can reach the person managing the list at
	wrf-users-owner at ucar.edu

When replying, please edit your Subject line so it is more specific than "Re: Contents of Wrf-users digest..."


Today's Topics:

   1. WRF DOMAIN AND MAP FACTOR (Luciano Ritter)


----------------------------------------------------------------------

Message: 1
Date: Sat, 2 Dec 2017 02:18:02 -0200
From: Luciano Ritter <nolascojr1465 at gmail.com>
To: wrf-users at ucar.edu
Subject: [Wrf-users] WRF DOMAIN AND MAP FACTOR
Message-ID:
	<CAGdSY1OSA24eVMMa9QOn8U2ktqGFQqTsW3aCc2g_CLy_+aZ5qw at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Hi,

I am starting with WRF model and I have a quest about the domain resolution (dx and dy).
In the manuals that i saw, they only specified that the dx and dy have to be in meters in ARW mode. Ok. But, there is some multiple value of the input data that we have to respect? For example, if I use GFS data with 1 degree of resolution, I must set dx and dy with 36 km? Some people that I know said that I have to calculate dx=(input data resolution)/(3 or 5 or 6)... This is right?

I found some things about map_factor, but in the tests that I made, all the resolutions set in dx and dy, the result is about 0.99999 and 1.002 or 1.009. They said that the map_factor should be about 1... But any resolution that I set, stays very closely to 1, so I don't understand that...

Can someone help me?

Sorry about my english problems, I am from Brazil and I am learning english.


Luciano Ritter
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ucar.edu/pipermail/wrf-users/attachments/20171202/d9abc4d0/attachment-0001.html>

------------------------------

Subject: Digest Footer

_______________________________________________
Wrf-users mailing list
Wrf-users at ucar.edu
http://mailman.ucar.edu/mailman/listinfo/wrf-users


------------------------------

End of Wrf-users Digest, Vol 160, Issue 1
*****************************************