[Wrf-users] default sigma level settings

[Eric Altshuler]

Hello Jorge,

I think the point of the original question was this: What are the sigma levels chosen by default when eta_levels is NOT specified? Suppose I set e_vert = 41 but don't specify eta_levels. What is the resulting distribution of sigma level values? There must be some formula in the code that calculates the 41 sigma values in this case, but it isn't clear how the default levels are calculated for a given value of e_vert.

Best regards,

Eric L. Altshuler
Assistant Research Scientist
Center for Ocean-Land-Atmosphere Studies
4041 Powder Mill Road, Suite 302
Calverton, MD 20705-3106
USA

E-mail: ela at cola.iges.org
Phone: (301) 902-1257
Fax: (301) 595-9793

----- Original Message -----
From: "Jorge Alejandro Arevalo Borquez" <jaareval at gmail.com>
To: "anis 980" <anis_980 at sina.com>
Cc: wrf-users at ucar.edu
Sent: Thursday, January 8, 2009 12:37:39 PM GMT -05:00 US/Canada Eastern
Subject: Re: [Wrf-users] default sigma level settings

Hi,
In WRF you can give explicitly the values for vertical levels, to do this
you need add eta_levels values like this:

 &domains
 eta_levels   = 1.0000, 0.9960, 0.9940, 0.9920, 0.9900,
                0.9880, 0.9850, 0.9820, 0.9780, 0.9740, 0.97, 0.965,
                0.96,   0.949,  0.937,  0.924,  0.909,
                0.892,  0.873,  0.851,  0.826,  0.798,
                0.768,  0.736,  0.702,  0.666,  0.629,
                0.5915, 0.5536, 0.5153, 0.4773, 0.44,
                0.404,  0.3695, 0.3375, 0.3085, 0.2845,
                0.2645, 0.2465, 0.2305, 0.2165, 0.2035,
                0.1915, 0.1792, 0.1667, 0.1539, 0.1407,
                0.1272, 0.1134, 0.0995, 0.0855, 0.0713,
                0.0571, 0.0520, 0.0480, 0.0429, 0.038,
                0.032,  0.0287, 0.022,  0.018,  0.0145, 0.007, 0.000,
 time_step                           = 200,
...
...


Best regards

2008/12/25 <anis_980 at sina.com>

>  Hello,
>   I am trying to run WRF ideal case em_quarter_ss, and I set "s_vert=1,
> e_vert=41 " in namelist.input file. But I want to know the sigma value of
> each level, does anyone know how does WRF model generate sigma values
> according the total number of vertical levels? What is the default sigma
> value according vertical level settings?
>  Best,
>  Leo
>
> _______________________________________________
> Wrf-users mailing list
> Wrf-users at ucar.edu
> http://mailman.ucar.edu/mailman/listinfo/wrf-users
>
>


-- 
Atentamente
Jorge Arévalo Bórquez

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