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Arw_post from version 2.2<br>
<br>
Gisele<br>
<br>
<br>
Em 26/1/2010 14:44, Jeffrey Duda escreveu:
<blockquote
cite="mid:c0f1d7891001260844x2d933a04n7ae3f72d9b88d8@mail.gmail.com"
type="cite">What are you using to post-process the data?<br>
<br>
Jeff<br>
<br>
<div class="gmail_quote">On Tue, Jan 26, 2010 at 10:42 AM, Gisele
Zepka <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:gzepka@dge.inpe.br">gzepka@dge.inpe.br</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000">
I am running my own wrf simulations.<br>
<br>
Gisele<br>
<br>
<br>
Em 26/1/2010 14:40, Jeffrey Duda escreveu:
<div>
<div class="h5">
<blockquote type="cite">Are you performing your own WRF simulations
or are you
obtaining past data from operationally run models?<br>
<br>
Jeff<br>
<br>
<div class="gmail_quote">On Tue, Jan 26, 2010 at 10:36 AM, Gisele
Zepka <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:gzepka@dge.inpe.br" target="_blank">gzepka@dge.inpe.br</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000">I will use temperature
and relative humidity at surface from wrf model
(TMPsfc and <span style="font-size: 11pt;"></span>RHsfc). <br>
I think that I need to find the surface pressure from the variable
pressfc.<br>
<br>
Gisele<br>
<br>
<br>
<br>
Em 26/1/2010 14:23, Jeffrey Duda escreveu:
<div>
<div>
<blockquote type="cite">Which model data are you using?
American
models should
have data for surface pressure. It's usually called pressfc.<br>
<br>
Jeff Duda<br>
<br>
<div class="gmail_quote">On Tue, Jan 26, 2010 at 10:08 AM,
Gisele
Zepka <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:gzepka@dge.inpe.br" target="_blank">gzepka@dge.inpe.br</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Well
I
have
a problem then.<br>
I run the wrf model and it has 42 levels. The surface pressure is
defined as 1013. This is my lowest level when I set z=1.<br>
I really don't know how to get this Mb.<br>
<br>
Gisele<br>
<br>
<br>
Em 26/1/2010 13:59, Andrew Revering escreveu:
<div>
<div><br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">If
you're
using GRIB data, you should find a SFC level. You don't want
to<br>
set it to 1013 because that isn't necessarily the suface. In many cases
that<br>
will be an imaginary, extrapolation below ground (in the mountains for<br>
example).<br>
<br>
Look for 'SFC' in the inventory of your GRIB data for the proper level.
You<br>
should be able to find Tc, Td, RH for the 'SFC' level in there to do the<br>
calculations.<br>
<br>
So to clarify... MB would be the MB at the Surface. How that’s defined<br>
exactly in your data set you'll have to figure out, but you don’t want
it to<br>
calculate it for 1013, unless you wanted a geopotential height like
850mb<br>
done.<br>
<br>
Andrew Revering<br>
Convective Development, Inc.<br>
<a moz-do-not-send="true"
href="http://www.convectivedevelopment.com/" target="_blank">http://www.convectivedevelopment.com/</a><br>
<br>
<br>
-----Original Message-----<br>
From: <a moz-do-not-send="true" href="mailto:GRADSUSR@LIST.CINECA.IT"
target="_blank">GRADSUSR@LIST.CINECA.IT</a> [mailto:<a
moz-do-not-send="true" href="mailto:GRADSUSR@LIST.CINECA.IT"
target="_blank">GRADSUSR@LIST.CINECA.IT</a>] On Behalf Of<br>
Gisele Zepka<br>
Sent: Tuesday, January 26, 2010 9:50 AM<br>
To: <a moz-do-not-send="true" href="mailto:GRADSUSR@LIST.CINECA.IT"
target="_blank">GRADSUSR@LIST.CINECA.IT</a><br>
Subject: Re: equivalent potential temperature<br>
<br>
Thanks a lot Andrew.<br>
<br>
As I said before, I will use model data to calculate theta-e. If I set<br>
the surface in the model, it is 1013 hPa. Is this the level that I need<br>
to consider in Mb (station pressure). If not, what is Mb? All Tc, Td and<br>
RH are catch in Mb level, aren't they?<br>
<br>
Gisele<br>
<br>
<br>
Em 26/1/2010 12:59, Andrew Revering escreveu:<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">You
can
calculate the Theta-E from ANY level. The typical levels of<br>
<br>
</blockquote>
interest<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">for
severe
weather are 850mb and the surface. Values of 330K or greater<br>
<br>
</blockquote>
are<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">usually
indicative
of instability great enough for severe weather. If<br>
<br>
</blockquote>
you're<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">looking
at
severe weather, I probably would use the surface. Likewise,
you<br>
can use the gradient you get from Theta-E, overlay wind barbs at the
level<br>
you're calculating (surface or 850) and you get a real nice idea of
where<br>
the boundaries are at that level.<br>
<br>
The disclaimer is there are a LOT of other parameters needed to really<br>
identify a situation as severe-worthy though.<br>
<br>
I don't know if GrADS has a function for it, but the 'saturated'
potential<br>
temperature (Theta-E) can be calculated with either of the following:<br>
<br>
Tc= temperature in degrees C<br>
Td = dew point temperature in degrees C (if needed)<br>
Mb = station pressure (be careful to note this is not sea level pressure<br>
<br>
</blockquote>
or<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">altimeter,
they
are all different)<br>
M = Mixing Ratio (calculations below if needed)<br>
RH = relative humidity<br>
Ms = Saturation Mixing Ratio (if needed, calculations below)<br>
Es = Dry Saturation Vapor Pressure (calculations below if needed)<br>
<br>
ThetaE = (Tc + 273.15) * ( 1000 / Mb ) ^ 0.286 + (3 * M)<br>
<br>
OR<br>
<br>
ThetaE = (273.15 + Tc) * ( 1000 / Mb ) ^ 0.286 + (3 * (RH * (3.884266 *
10<br>
<br>
</blockquote>
^<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">((
7.5
* Tc ) / ( 237.7 + Tc )) ) /100 ))<br>
<br>
<br>
M= RH*Ms/100<br>
OR<br>
M= ((0.622*E)/(Mb-E))*1000<br>
<br>
Ms = ((Val(RH) / 100) / Val(M)) * 100<br>
OR MORE ACCURATELY<br>
Ms = 0.622 * Es/(P - Es)<br>
<br>
Es = 6.1078 * exp([(9.5939 * Td) - 307.004]/[(0.556 * Td) + 219.522])<br>
<br>
Andrew Revering<br>
Convective Development, Inc.<br>
<a moz-do-not-send="true"
href="http://www.convectivedevelopment.com/" target="_blank">http://www.convectivedevelopment.com/</a><br>
<br>
-----Original Message-----<br>
From: <a moz-do-not-send="true" href="mailto:GRADSUSR@LIST.CINECA.IT"
target="_blank">GRADSUSR@LIST.CINECA.IT</a> [mailto:<a
moz-do-not-send="true" href="mailto:GRADSUSR@LIST.CINECA.IT"
target="_blank">GRADSUSR@LIST.CINECA.IT</a>] On Behalf<br>
<br>
</blockquote>
Of<br>
<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Gisele
Zepka<br>
Sent: Tuesday, January 26, 2010 8:40 AM<br>
To: <a moz-do-not-send="true" href="mailto:GRADSUSR@LIST.CINECA.IT"
target="_blank">GRADSUSR@LIST.CINECA.IT</a><br>
Subject: equivalent potential temperature<br>
<br>
Dear all,<br>
<br>
I am interested to analyse the atmospheric instability when a storm<br>
occurrs using equivalent potential temperature from mesoscale model.<br>
What atmospheric level do I need to check to get an idea of instability?<br>
I don't have a theta_e output, so I will calculate it from temperature<br>
and humidity data from model.<br>
<br>
Please, any help will be nice.<br>
<br>
Thanks.<br>
Gisele<br>
<br>
<br>
<br>
</blockquote>
<br>
<br>
</blockquote>
<br>
<br>
-- <br>
Msc. Gisele dos Santos Zepka<br>
Atmospheric Electricity Group (ELAT)<br>
National Institute for Space Research (INPE)<br>
Av. dos Astronautas, 1758<br>
São José dos Campos/ SP/ Brazil CEP 12227-010<br>
Phone ++55(12)39456841<br>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Jeff Duda<br>
Iowa State University<br>
Meteorology Graduate Student<br>
3134 Agronomy Hall<br>
<a moz-do-not-send="true"
href="http://www.meteor.iastate.edu/%7Ejdduda" target="_blank">www.meteor.iastate.edu/~jdduda</a><br>
</blockquote>
<br>
<br>
<pre cols="72">--
Msc. Gisele dos Santos Zepka
Atmospheric Electricity Group (ELAT)
National Institute for Space Research (INPE)
Av. dos Astronautas, 1758
São José dos Campos/ SP/ Brazil CEP 12227-010
Phone ++55(12)39456841 </pre>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Jeff Duda<br>
Iowa State University<br>
Meteorology Graduate Student<br>
3134 Agronomy Hall<br>
<a moz-do-not-send="true"
href="http://www.meteor.iastate.edu/%7Ejdduda" target="_blank">www.meteor.iastate.edu/~jdduda</a><br>
</blockquote>
<br>
<br>
<pre cols="72">--
Msc. Gisele dos Santos Zepka
Atmospheric Electricity Group (ELAT)
National Institute for Space Research (INPE)
Av. dos Astronautas, 1758
São José dos Campos/ SP/ Brazil CEP 12227-010
Phone ++55(12)39456841 </pre>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Jeff Duda<br>
Iowa State University<br>
Meteorology Graduate Student<br>
3134 Agronomy Hall<br>
<a moz-do-not-send="true"
href="http://www.meteor.iastate.edu/%7Ejdduda">www.meteor.iastate.edu/~jdduda</a><br>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Msc. Gisele dos Santos Zepka
Atmospheric Electricity Group (ELAT)
National Institute for Space Research (INPE)
Av. dos Astronautas, 1758
São José dos Campos/ SP/ Brazil CEP 12227-010
Phone ++55(12)39456841 </pre>
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