<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Hi Brandt Naxwell,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">thank you very much for all your very clear explanations.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">It seems that, considering an ideal atmosphere we can inclusively from the hydrostatic equation set the model first level. I mean ... from the equation p(z) = po exp(-z/H), where H = RT/g0, z is given in km, and po = 101300,0 Pa (atmospheric pressure at surface), we can compute a pressure value related to any height and include it in the model. Is it correct?</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"> </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Thank you again.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"> </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_extra"><br clear="all"><div><div data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><font color="#333333"><span style="background-color:rgb(255,255,255)">José Augusto P. Veiga</span></font></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><span style="color:rgb(51,51,51);font-family:arial;font-size:small">CREA n.: 24161</span></span></div><div><span style="border-collapse:collapse"><font color="#333333"><font face="arial" size="2"><br></font>==============================<wbr>========</font></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><font color="#333333">Universidade do Estado do Amazonas <br>Departamento de Meteorologia<br><span style="border-collapse:separate;font-family:arial;font-size:small">Escola Superior de Tecnologia (EST)</span></font></span><span style="font-family:arial;font-size:small;color:rgb(51,51,51)"> </span></div><div><span style="color:rgb(51,51,51)">==============================<wbr>========</span><br></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><span style="border-collapse:separate;font-family:arial;font-size:small"><font color="#333333">Av. Darcy Vargas, 1200, Manaus-AM Brasil<br>Work phone: (92) 3878 4317, Ramal 4317<br>Skype:<span style="background-color:rgb(255,255,255)"> veiga_j.a.p.</span><br></font></span></span></div><div><span style="color:rgb(51,51,51)">==============================<wbr>========</span><font color="#333333"><br>CV: <a href="http://lattes.cnpq.br/4027612512091565" target="_blank"><font style="background-color:rgb(255,255,255)" color="#333333">http://lattes.cnpq.br/<wbr>4027612512091565</font></a><br>Site: </font><a href="https://scientificmet.wordpress.com" target="_blank">https://scientificmet.<wbr>wordpress.com</a><font color="#333333"><br></font><span style="color:rgb(51,51,51)">==============================<wbr>========</span></div><div><font color="#333333"><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></font></div><div><font color="#333333"><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></font></div><div><font color="#333333"><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></font></div></div></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Tue, Sep 6, 2016 at 3:06 PM, Brandt Maxwell - NOAA Federal <span dir="ltr"><<a href="mailto:brandt.maxwell@noaa.gov" target="_blank">brandt.maxwell@noaa.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div>Jose,<br><br></div>First of all, I think these should be sigma levels, even though they're called eta levels in WRF. The sigma levels are based on pressure, so one can calculate approximately how many levels would be below the pressure found at 1 km above the surface (though not this will vary based on surface elevation, temperature in the layer, among other things).<br><br></div>If you have a surface (for simplicity sake) of 1010 mb and a top of 10 mb (many of us will have a lower top), then 0,001 in the sigma coordinates would equate to about 1 mb. 1 km above the surface would be around 900 mb given the above surface pressure, so you can approximate anything between sigma levels of .890 and 1.000 to be below 1 km (you can use a standard atmosphere calculator to see how things like temperature can affect this). If your model top is really low, like 100 mb, then your 1 km sigma level would be more like .880.<br><br></div>Later...<br></div>Brandt Maxwell<br></div>National Weather Service/San Diego<br> <br><div><div><div><div><br><br></div></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Sun, Sep 4, 2016 at 4:03 PM, Jose Augusto Paixão Veiga <span dir="ltr"><<a href="mailto:veiga.uea@gmail.com" target="_blank">veiga.uea@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Dear all,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I am using the following eta levels in my runs with WRF (38 in this case). </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default"><p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b>eta_levels = 1.000, 0.995, 0.990, 0.985, 0.980, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.970, 0.960, 0.950, 0.940, 0.930, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.920, 0.910, 0.900, 0.880, 0.860, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.830, 0.800, 0.770, 0.740, 0.710, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.680, 0.640, 0.600, 0.560, 0.520, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.480, 0.440, 0.400, 0.360, 0.320, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.280, 0.240, 0.200, 0.160, 0.120, </b></p>
<p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><b> 0.080, 0.040, 0.000</b></p><p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><br></p><p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><br></p>However, I would like to know how many levels, in this example, are included (a) in the first km and (b) how can I identify the eta level representing the first km? </div><div class="gmail_default"><br></div><div class="gmail_default">I really appreciate any comment on this issue.</div><div class="gmail_default"><br></div><div class="gmail_default">Thanks.</div><div class="gmail_default"><br></div><div class="gmail_default"><br></div><div class="gmail_default"> <p style="font-family:'andale mono';margin:0px;font-size:13px;line-height:normal;color:rgb(195,55,32)"><br></p></div><div><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><font color="#333333"><span style="background-color:rgb(255,255,255)">José Augusto P. Veiga</span></font></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><span style="color:rgb(51,51,51);font-family:arial;font-size:small">CREA n.: 24161</span></span></div><div><span style="border-collapse:collapse"><font color="#333333"><font size="2" face="arial"><br></font>==============================<wbr>========</font></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><font color="#333333">Universidade do Estado do Amazonas <br>Departamento de Meteorologia<br><span style="border-collapse:separate;font-family:arial;font-size:small">Escola Superior de Tecnologia (EST)</span></font></span><span style="font-family:arial;font-size:small;color:rgb(51,51,51)"> </span></div><div><span style="color:rgb(51,51,51)">==============================<wbr>========</span><br></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><span style="border-collapse:separate;font-family:arial;font-size:small"><font color="#333333">Av. Darcy Vargas, 1200, Manaus-AM Brasil<br>Work phone: (92) 3878 4317, Ramal 4317<br>Skype:<span style="background-color:rgb(255,255,255)"> veiga_j.a.p.</span><br></font></span></span></div><div><span style="color:rgb(51,51,51)">==============================<wbr>========</span><font color="#333333"><br>CV: <a href="http://lattes.cnpq.br/4027612512091565" target="_blank"><font style="background-color:rgb(255,255,255)" color="#333333">http://lattes.cnpq.br/40276125<wbr>12091565</font></a><br>Site: </font><a href="https://scientificmet.wordpress.com" target="_blank">https://scientificmet.wo<wbr>rdpress.com</a><font color="#333333"><br></font><span style="color:rgb(51,51,51)">==============================<wbr>========</span></div><div><font color="#333333"><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></font></div><div><font color="#333333"><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></font></div><div><font color="#333333"><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><br></span></font></div></div></div></div></div></div></div></div></div></div></div>
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