<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;color:rgb(0,0,0)">Thanks Eric! I will look into using 3 nests. <br>Just to clarify, if I use time step of 60sec for parent domain and parent_time_step_ratio of 6, the nest domain will run at 10sec, correct? I suspect a small time step (like 10 sec) is needed for such fine resolution domain (e.g. 1km). Why did you say that would make the time step too large on the nest domain?</div>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Jun 9, 2014 at 1:10 PM, Eric Altshuler <span dir="ltr"><<a href="mailto:ela@cola.iges.org" target="_blank">ela@cola.iges.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-family:arial,helvetica,sans-serif;font-size:12pt;color:#000000">I would think a nest grid ratio of 15 is too large. The recommended value is 3, and 5 can also be used. Also, your time step ratio is 6, which would probably make the time step too large on your nest domain with a grid ratio of 15. You need to use a triple nest if your high resolution domain is 1 km. One suggestion might be:<div>
<br></div><div>dx = 15000, 5000, 1000</div><div>dy = 15000, 5000, 1000</div><div>parent_grid_ratio = 1, 3, 5</div><div>parent_time_step_ratio = 1, 3, 5</div><div><br></div><div>or:</div><div><br></div><div><div>dx = 15000, 3000, 1000</div>
<div>dy = 15000, 3000, 1000</div><div>parent_grid_ratio = 1, 5, 3</div><div>parent_time_step_ratio = 1, 5, 3</div></div><div><br></div><div>I'm not sure which one is preferable.</div><div><br></div><div>Best regards,</div>
<div><br></div><div><br><br><div><span name="x"></span>Eric L. Altshuler<br>Research Scientist<br>Center for Ocean-Land-Atmosphere Studies<br>253 Research Hall, Mail Stop 6C5<div>George Mason University</div><div>4400 University Drive<br>
Fairfax, VA 22030 USA<br><br>E-mail: <a href="mailto:ela@cola.iges.org" target="_blank">ela@cola.iges.org</a><br>Phone: <a href="tel:%28703%29%20993-5725" value="+17039935725" target="_blank">(703) 993-5725</a><br>Fax: <a href="tel:%28703%29%20993-5770" value="+17039935770" target="_blank">(703) 993-5770</a></div>
<span name="x"></span><br></div><br><hr><b>From: </b>"Xin Xi" <<a href="mailto:xxi@gatech.edu" target="_blank">xxi@gatech.edu</a>><br><b>To: </b><a href="mailto:wrf-users@ucar.edu" target="_blank">wrf-users@ucar.edu</a><br>
<b>Sent: </b>Monday, June 9, 2014 11:12:26 AM<br><b>Subject: </b>[Wrf-users] Fwd: two way nest run crashes without errors<br><br><div dir="ltr"><div><div class="h5">Hi I am running wrf 3.6 with two way nesting. After the spinning up on outer domain, the program stopped without any warning or errors. in other words, the program simply stopped at the beginning of the nest domain start time. I wonder whether this is an issue of parent_grid_ratio (=15), time step or the vertical lvls. Please help. Thanks.<br>
<div class="gmail_quote"><div dir="ltr"><div dir="ltr"><div>
<br> Here is excerpt of namelist.input:<br><br> &time_control<br> run_days = 3,<br> run_hours = 13,<br> run_minutes = 0,<br> run_seconds = 0,<br>
start_year = 2013, 2013, 2000,<br> start_month = 03, 03, 01,<br> start_day = 10, 11, 24,<br> start_hour = 12, 00, 12,<br>
start_minute = 00, 00, 00,<br> start_second = 00, 00, 00,<br> end_year = 2013, 2013, 2000,<br> end_month = 03, 03, 01,<br>
end_day = 14, 14, 25,<br> end_hour = 00, 00, 12,<br> end_minute = 00, 00, 00,<br> end_second = 00, 00, 00,<br>
interval_seconds = 21600<br> input_from_file = .true.,.true.,.true.,<br> history_interval = 60, 60, 60,<br> frames_per_outfile = 24, 24, 1000,<br>
restart = .false.,<br> restart_interval = 5000,<br> io_form_history = 2<br> io_form_restart = 2<br> io_form_input = 2<br>
io_form_boundary = 2<br> debug_level = 5000<br> fine_input_stream = 0, 2, 2,<br> io_form_auxinput2 = 2<br> /<br><br> &domains<br> time_step = 60,<br>
time_step_fract_num = 0,<br> time_step_fract_den = 1,<br> max_dom = 2,<br> e_we = 50, 166, 94,<br> e_sn = 50, 166, 91,<br>
e_vert = 57, 57, 30,<br> p_top_requested = 5000,<br> num_metgrid_levels = 27,<br> num_metgrid_soil_levels = 4,<br> dx = 15000, 1000, 3333.33,<br>
dy = 15000, 1000, 3333.33,<br> grid_id = 1, 2, 3,<br> parent_id = 0, 1, 2,<br> i_parent_start = 1, 20, 30,<br>
j_parent_start = 1, 20, 30,<br> parent_grid_ratio = 1, 15, 3,<br> parent_time_step_ratio = 1, 6, 3,<br> feedback = 1,<br>
smooth_option = 0,<br> eta_levels = 1.000, 0.999, 0.998, 0.997, 0.996, 0.995, 0.994, 0.993,<br> 0.991, 0.988, 0.985, 0.982, 0.978, 0.974, 0.970, 0.965,<br>
0.960, 0.955, 0.950, 0.945, 0.935, 0.925, 0.915, 0.905,<br> 0.895, 0.875, 0.855, 0.840, 0.820, 0.800, 0.760, 0.720,<br> 0.680, 0.640, 0.600, 0.575, 0.525, 0.485, 0.445, 0.400,<br>
0.350, 0.300, 0.285, 0.251, 0.217, 0.192, 0.164, 0.141,<br> 0.119, 0.103, 0.083, 0.067, 0.055, 0.043, 0.033, 0.024,<br> 0.000,<br>
<br> /<br><br></div></div>
</div>
</div><br><br clear="all"><br></div></div><span class="HOEnZb"><font color="#888888">-- <br><font><i style="font-family:arial narrow,sans-serif">Xin Xi<br>School of Earth and Atmospheric Sciences<br>Georgia Institute of Technology<br>
311 Ferst Drive, Atlanta, GA 30332-0340</i></font><br>
</font></span></div><span class="HOEnZb"><font color="#888888">
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</font></span></div></div></div></blockquote></div><br><br clear="all"><br>-- <br><font><i style="font-family:arial narrow,sans-serif">Xin Xi<br>School of Earth and Atmospheric Sciences<br>Georgia Institute of Technology<br>
311 Ferst Drive, Atlanta, GA 30332-0340</i></font><br>
</div>