<div dir="ltr"><div><div><div><div>This likely isn't a problem with grads. Grads is returning the undef value. If you take a look at the region around that point, at 1000mb most land points are undef. This is because MERRA does not extrapolate to pressure levels > Ps.<br>
<br><a href="http://gmao.gsfc.nasa.gov/research/merra/pressure_surface.php">http://gmao.gsfc.nasa.gov/research/merra/pressure_surface.php</a><br><br></div>So, check PS to see if it is < 1000mb. It maybe a land point. If a water point is OK to use in your work, move just a bit into the Meditterenean Sea and you should find real values. but it is possible that there may be undeffs over water, if the Ps becomes <1000.<br>
<br></div>If you really want data at this point, you can compute RH using surface data, or, there is a third party routine available to perform the extrapolation to values under the surface.<br><br><a href="https://reanalyses.org/atmosphere/extrapolation-merra-reanalyses-obtain-continuous-fields">https://reanalyses.org/atmosphere/extrapolation-merra-reanalyses-obtain-continuous-fields</a><br>
<br></div>If you find that this is not a grads issue, feel free to contact me offline, or use the <a href="mailto:merra-questions@lists.nasa.gov">merra-questions@lists.nasa.gov</a> listserv.<br><br></div>Mike<br></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Fri, Jul 19, 2013 at 5:51 AM, avi kojokro <span dir="ltr"><<a href="mailto:kojokroavi@gmail.com" target="_blank">kojokroavi@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="rtl"><div dir="ltr" style="text-align:left"><span lang="en"><span>I'm trying</span> <span>to calculate</span> <span>a monthly average of</span> <span>relative humidity,</span> <span>but the answer</span> <span>of</span> <span>Grads</span> <span>unreasonable</span><span>.</span><br>
<span>Is</span> <span>the script</span> <span>right?</span> <span>I attach</span> <span>it.</span><br><span>I am</span> <span>also</span> <span>attaching</span> <span>a</span> <span>screenshot</span> <span>of</span> <span>Grads</span> <span>answer</span><span>.<br>
<br></span></span></div><div dir="ltr" style="text-align:left"><span lang="en"><span>The </span></span><span lang="en"><span>Script: <br><br><br>'reinit'<br>
'c'<br>'set display color white'<br>'c'<br>'sdfopen <a href="http://goldsmr3.sci.gsfc.nasa.gov:80/dods/MATMCPCLD" target="_blank">http://goldsmr3.sci.gsfc.nasa.gov:80/dods/MATMCPCLD</a>'<br>
'set lev 1000'<br>
'set lat 32.0'<br>'set lon 35.0'<br>yr=1979<br>tt=''<br>while(yr<=2013)<br>'set time 1MAY'yr<br>'q time'<br>say ' 'result<br>*'set gxout print'<br>'d rh'<br>
tt1=subwrd(result,4)<br>tt=tt' 'tt1<br>say ' 'result<br>yr=yr+1<br>endwhile<br>say 'apr <a href="tel:%281979-2013%29%20850" value="+19792013850" target="_blank">(1979-2013) 850</a>_hgt [m] : 'tt<br>
<br><br><br><br></span></span></div></div>
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<br></blockquote></div><br></div>