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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
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Hi Simon- > Full Name: Simon Metcalf > Email Address: address@hidden > Organization: NSW Rural Fire Service > Package Version: 2.7u2 build date:2009-08-26 16:33 UTC > Operating System: Windows XP > Hardware: Java: home: C:\Program Files\IDV_2.7u2\jre version: 1.6.0_13 > j3d:1.5.2 fcs (build4) > Description of problem: Hi, > > IDV is not handling the units for its dewpoint depression function. The > function relies upon calculating dewpoint from temp and relhum in my data. > The unit for temp in my data is Kelvin, but IDV outputs dewpoint in degrees > Celsius, so when it attempts to calculate dewpoint depression, it uses temp > in Kelvin from the file and dewpoint in celsius from its calculation. It may > well be accounting for this in the calculation, but the resultant dewpoint > depression calculation thinks it's in Celcius when the data looks more like > Kelvin, leading to display and further calculation problems. It may well be > getting the function for dewpoint depression wrong because of the mixup in > units. The problem is that the IDV does not have a notion of "delta" units. So, it sees K and thinks it's absolute degrees so when it converts to Celsius, it adds ~273.15. > Is there a possible solution to this problem as intend to use dewpoint > depression in further calculations. The only suggestion I have is to use the noUnit procedure I sent yesterday to strip off the units once you've calculated the dewpoint depression. Don Murray Ticket Details =================== Ticket ID: IXS-684583 Department: Support IDV Priority: Critical Status: Open