<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000'>Hi, Giacomo.<br><br>1) I would suggest you to try low levels between 1000 and 700 hPa to see which one gives you the most significant signal, according your objectives.<br><br>2) As your mixr is multiplied by 1000, it must have units of grams per kilograms (please, display mixr to see if it is g/kg: something like 1, 5, 10, 20 g/kg is the expected magnitude for mixr in g/kg). So, the units of mconv is just (g/kg)/s, that is, how much water vapor in grams (in each kilogram of ar) is converging or diverging in each second on a point (x,y) at that level.<br><br>3) The answer is yes. Probably, the td field given by your (dynamical) model is more consistent than the "fitted curve" given by the formula in the script, which needs a lot of combinations between variables.<br><br>Hope this helps,<br>Ricardo<br><br><hr id="zwchr"><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;">
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<div dir="ltr">Hi, I've found a grads script for calculating Moisture Convergence (mconv.gs)<div>But I have 3 questions:</div><div><br></div><div>1)I have to set a level: which one should I use? Maybe 1000 hPa?</div><div><br></div><div>2)Which is the unit of measure of moisture convergence? Which range of values could I use (for example 0 to ?? And by steps of?)</div><div><br></div><div>This is the script:<br><pre style="word-wrap: break-word; white-space: pre-wrap;">* This is a script for displaying moisture convergence
* Written by Michael Maxwell
*
* rh = Relative Humidity in %
* t = Temp at *set level in degrees Kelvin
* tc = Temp in degrees C
* td = Dewpoint at *set level in degrees C
* e = Vapor pressure
* mixr = Mixing ratio
* u = U-wind in m/s
* v = V-wind in m/s
* mconv = moisture convergence/divergence. convergence is positive and divergence is negative.
'tc = (t-273.16)'
'td = tc-((14.55+0.114*tc)*(1-0.01*rh) + pow((2.5+0.007*tc)*(1-0.01*rh),3) + (15.9+0.117*tc)*pow((1-0.01*rh),14))'
'vapr = 6.112*exp((17.67*td)/(td+243.5))'
'e = vapr*1.001+(lev-100)/900*0.0034'
'mixr = 0.62197*(e/(lev-e))*1000'
'mconv = (-1)*hdivg(u*mixr,v*mixr)*1e4'
'd mconv'</pre><pre style="word-wrap: break-word; white-space: pre-wrap;"><span style="font-family: Calibri, sans-serif; white-space: normal;">3)Could I delete "td", since WRF-NMM already gives me it?<br><br>Thanks,</span></pre><pre style="word-wrap: break-word; white-space: pre-wrap;"><span style="font-family: Calibri, sans-serif; white-space: normal;">Giacomo</span></pre><pre style="word-wrap: break-word; white-space: pre-wrap;"><br></pre></div> </div>
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