<div dir="ltr">
<p class="MsoNormal">hi, </p><p class="MsoNormal"><br></p><p class="MsoNormal">thank you Kyle</p><p class="MsoNormal"><br></p><p class="MsoNormal"><br></p><p class="MsoNormal"><br></p><p class="MsoNormal">I have calculated the divergence of wind at 850 hPa level and multiplied by specific humidity (q)
at 850 hPa level. </p>
<p class="MsoNormal">Moisture flux= q* wind(u,v)</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">div=</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(200,20,201)">uv2dvG_Wrap</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(u_850_clim,v_850_clim); divergence at pressure
level 850</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">moisture flux= div*psl_clim
;psl_clim –>specific humidity</span></p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Then I tried to use the function <span style="font-family:'Lucida Sans';color:rgb(9,63,124)">dpres_plevel_Wrap to find out the pressure level thickness and will be
planning to integrate the moisture flux as explained in the example number 2 (</span><a href="http://www.ncl.ucar.edu/Document/Functions/Contributed/dpres_plevel_Wrap.shtml">http://www.ncl.ucar.edu/Document/Functions/Contributed/dpres_plevel_Wrap.shtml</a>
<span style="font-family:'Lucida Sans';color:rgb(9,63,124)">)below the explanation for the
function dpres_plevel_Wrap.</span></p>
<p class="MsoNormal"><span style="font-family:'Lucida Sans';color:rgb(9,63,124)"> </span></p>
<p class="MsoNormal"><span style="font-family:'Lucida Sans';color:rgb(9,63,124)">When I try to find out </span><span style="font-size:13pt;font-family:Courier">dp = <a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/dpres_plevel.shtml"><b><span style="font-family:Verdana;color:rgb(0,29,255);text-decoration:none">dpres_plevel</span></b></a>(lev,
psfc, ptop, 0), I am getting the error as follows:</span></p>
<p class="MsoNormal"><span style="font-size:13pt;font-family:Courier"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">warning:dpres_plevel: At one or more
grid points the sum of the layer thicknesses is not equal to (psfc-ptop). Are
units of plev, psfc and ptop matching?</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">fatal:Mul: Number of dimensions do not match, can't continue</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">however, the units of all lev,psfc,ptop are all similar in the ncl
script.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">;==============================</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">lev = u_ctl ->z11_p_level ;17
pressure levels from u compont of wind data</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">ps_ctl= </span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(46,174,187)">addfile</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">"<a href="http://ps_197001_200112.nc">ps_197001_200112.nc</a>"</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">,</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">"r"</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">) ;surface
pressure data</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">psf = ps_ctl->ps</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">psfc =psf(:,</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">0</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">:</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">143</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">,:) ; in order
to get 144 lat points</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">ptop = lev(</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">14</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">) ; pressure
level 850hPa</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">dsize=</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(46,174,187)">dimsizes</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(psfc)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">lonn=dsize(</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">2</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">latn=dsize(</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">1</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">n2=</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">30</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black"></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">ps_jjas=</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">new</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">(/</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">n2,latn,lonn</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">/)</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">,</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">float</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">do</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> y=</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">0</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">,n2-</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">1</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black"></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">ps_jjas(y,:,:)=</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(200,20,201)">dim_avg_n_Wrap</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">((psfc((</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">4</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">+(y*</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">12</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">)):(</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">7</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">+(y*</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">12</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">)),:,:)),</span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">0</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">) ; seasonal mean of 30 years</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">end</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(193,101,28)">do</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black"></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(46,174,187)">printVarSummary</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(psfc)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(46,174,187)">printVarSummary</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(ptop)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(46,174,187)">printVarSummary</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(lev)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">dp
= </span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(46,174,187)">dpres_plevel</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">(lev, ps_jjas, ptop, </span><span style="font-size:11pt;font-family:'Menlo Regular';color:rgb(180,36,25)">0</span><span style="font-size:11pt;font-family:'Menlo Regular';color:black">)</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Menlo Regular';color:black">After calculating dp, I would like to use the function </span><span style="font-family:Verdana"><a href="http://www.ncl.ucar.edu/Document/Functions/Contributed/dim_sum_n_Wrap.shtml"><b><span style="color:windowtext;text-decoration:none">dim_sum_n_Wrap</span></b></a> to integrate vertically.</span></p>
<p class="MsoNormal"><span style="font-family:Verdana"> </span></p>
<p class="MsoNormal"><span style="font-family:Verdana">But, I am not sure whether
I am moving in a correct way to find out vertically integrated moisture flux convergence
between two pressure levels. </span></p>
<p class="MsoNormal"><span style="font-family:Verdana"> </span></p>
<p class="MsoNormal"><span style="font-family:Verdana">I am very new to ncl, so I
hope some one will help me to sort out the problem.</span><span style="font-family:'Lucida Sans';color:rgb(9,63,124)"></span></p><p class="MsoNormal"><span style="font-family:Verdana"><br></span></p><p class="MsoNormal"><font face="Verdana">any help will be highly appreciated</font></p><p class="MsoNormal"><font face="Verdana"><br></font></p><p class="MsoNormal"><font face="Verdana">thanks</font></p><p class="MsoNormal"><font face="Verdana"><br></font></p><p class="MsoNormal"><font face="Verdana">thomas</font></p>
</div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Dec 27, 2014 at 1:02 PM, Kyle Griffin <span dir="ltr"><<a href="mailto:ksgriffin2@wisc.edu" target="_blank">ksgriffin2@wisc.edu</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">Thomas,<div><br></div><div>This is not an NCL issue, this is a science issue. The functions are well-documented, as you most definitely seem to understand what each function is calculating.</div><div><br></div><div>Only YOU can say whether your calculation should include or exclude the boundary levels - generally I would include them, but it depends on the science you want to do.</div><div><br></div><div>If you can calculate the moisture flux itself (a simple calculation), I would vertically integrate that and then calculate the divergence of the resulting field as this will be more efficient. However, I'm not sure if it would yield the same result as calculating the moisture flux divergence and then doing the vertical integral - you can certainly try both methods and be aware the second method will take longer to calculate.</div><div><br></div><div>Don't forget to look at the code that Dennis sent you in a previous email as well - some or all of it might help outline what you want to do.</div><div><br></div><div>Hope this helps. If not, consult the mathematical equations for this field and respond back to ncl-talk if you have issues implementing the calculations within your NCL scripts.</div><div><br></div><div><br></div><div>Kyle</div></div><div class="gmail_extra"><br clear="all"><div><div><div dir="ltr">----------------------------------------<div>Kyle S. Griffin</div><div>Department of Atmospheric and Oceanic Sciences</div><div>University of Wisconsin - Madison</div><div>Room 1421</div><div>1225 W Dayton St, Madison, WI 53706</div><div>Email: <a href="mailto:ksgriffin2@wisc.edu" target="_blank">ksgriffin2@wisc.edu</a></div></div></div></div>
<br><div class="gmail_quote"><div><div class="h5">On Thu, Dec 25, 2014 at 9:57 PM, tms_l <span dir="ltr"><<a href="mailto:littithomas@gmail.com" target="_blank">littithomas@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 class="h5"><div dir="ltr"><div style="font-size:13px">hi ncl users</div><div style="font-size:13px"><br></div><div style="font-size:13px">I have to calculate the moisture flux convergence between pressure levels 850hpa AND 200hpa pressure levels..and I THINK i need to consider the specific humidity at 850 & 200 hpa pressure levels too ...finally integrating between the two pressure levels to get the moisture flux convergence...</div><div style="font-size:13px"><br></div><div style="font-size:13px">I already calculated the wind divergence at two pressure levels using the function, uv2dvG_Wrap..I am not clear about the next step..</div><div style="font-size:13px"><br></div><div style="font-size:13px">can anyone describe it little more..which functions i need to select for calculating the moisture flux convergence..</div><div style="font-size:13px"><br></div><div> thanks in advance</div><div><br></div><div>thomas</div></div>
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