<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>One option is to simply download vp data in a grads netcdf format from here:</span></div><div><span><a href="http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.DAILY/.Intrinsic/.PressureLevel/.vpot/">http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.DAILY/.Intrinsic/.PressureLevel/.vpot/</a></span></div><div><span></span> </div><div><span>or in monthly format:</span></div><div><span><a href="http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.MONTHLY/.Intrinsic/.PressureLevel/">http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.MONTHLY/.Intrinsic/.PressureLevel/</a></span></div><div><span></span> </div><div><span>You can subset and select various times and regions for your needs through this site as well. This does not necessarily answer your question of
how to accomplish this calculation in GrADS, but at least you will now have access to it and can use it in GrADS. </span></div><div><span></span> </div><div><span>good luck,</span></div><div><span>teddy </span></div><div></div><div> </div><div><a href="http://www.teddyallen.com/" rel="nofollow" target="_blank">http://www.teddyallen.com/</a></div><div>"To move quickly, go alone. To move far, go <font color="#ff0000"><i><strong>together</strong></i></font>." </div><div>African Proverb</div><div><br><blockquote style="padding-left: 5px; margin-top: 5px; margin-left: 5px; border-left-color: rgb(16, 16, 255); border-left-width: 2px; border-left-style: solid;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font size="2" face="Arial"> <div style="margin: 5px 0px; padding: 0px; border: 1px solid rgb(204, 204,
204); height: 0px; line-height: 0; font-size: 0px;" class="hr" contentEditable="false" readonly="true"></div> <b><span style="font-weight: bold;">From:</span></b> Arlindo Meque <mequitomz@yahoo.com.br><br> <b><span style="font-weight: bold;">To:</span></b> gradsusers <gradsusr@gradsusr.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, February 28, 2013 4:13 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> [gradsusr] How to calculate the velocity potential for a local domain ?<br> </font> </div> <br>
<div id="yiv189859028"><div><div style="color: rgb(0, 0, 0); font-family: times new roman, new york, times, serif; font-size: 12pt; background-color: rgb(255, 255, 255);"><div><span><br></span></div><div>
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<div style="margin-bottom: 0cm;">Dear all,</div>
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<div style="margin-bottom: 0cm;">I have wind fields covering only
the African domain and I want to calculate the velocity potential.</div>
<div style="margin-bottom: 0cm;"><br>
</div>
<div style="margin-bottom: 0cm;">To my knowledge, the classical “fish”
algorithm under the opengrads version works for a global domain.
</div>
<div style="margin-bottom: 0cm;"><br>
</div>
<div style="margin-bottom: 0cm;">Any suggestion?</div>
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<div style="margin-bottom: 0cm;">Arlindo
</div>
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