This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
> Yuan, > > And Equivalent Potential Temperature(Theta-E)? > > Thanks! This one is tricky, I can see the procedure of calculation is: AdiabaticEquivalentTemperature is calculated from the temp and mixingratio and PotentialTemperature is calculated from the pressure and AdiabaticEquivalentTemperaturet and EquivalentPotentialTemperature is PotentialTemperature. Yuan > > Stefan > -- > Stefan Cecelski > Ph.D. Candidate and Graduate Research Assistant > AOSC Department: University of Maryland College Park > 2343 Computer and Space Sciences Building(CSS #224) > 703.801.1370 > address@hidden > > On Tue, May 17, 2011 2:53 pm, Unidata IDV Support wrote: > >> Julien, > >> > >> That is ok. Here are two I keep getting questions about: > >> > >> Horizontal Flux Divergence > > > > horizontal scalar flux divergence defined as u*(dp/dx) + v*(dp/dy) + > > p*(du/dx + dv/dy) > >> Potential Temperature > > > > theta = t * (1000/p)** .286 > > > > The url of the user guide may have some information you are looking for: > > > > http://www.unidata.ucar.edu/software/idv/docs/userguide/tools/JythonLib.html > > > > > > Yuan > >> > >> Thanks! > >> > >> Stefan > >> -- > >> Stefan Cecelski > >> Ph.D. Candidate and Graduate Research Assistant > >> AOSC Department: University of Maryland College Park > >> 2343 Computer and Space Sciences Building(CSS #224) > >> 703.801.1370 > >> address@hidden > >> > >> On Fri, May 13, 2011 1:58 pm, Unidata IDV Support wrote: > >> >> Julien, > >> >> > >> >> Before we open another can of worms, I would like to make one > >> request. I > >> >> have convinced my research group at UMD to use IDV(~5 students). For > >> our > >> >> research, we NEED to know the formulas we use to calculate variables > >> >> such > >> >> as Theta-e, Horizontal Flux Divergence and so forth. There are > >> copious > >> >> ways of calculating these variables, and literature proves that some > >> >> ways > >> >> are more accurate than others. I would like to request that a PDF > >> >> document, or some literature is created that lists how the derived > >> >> variables in the IDV are calculated. I understand in the formula > >> editor > >> >> we > >> >> can see which variables are going into it, but we need documentation > >> on > >> >> the actual formulas used. For example, there are at least 3 different > >> >> ways > >> >> to calculate Theta-e(Equivalent Potential Temp). It has been shown > >> that > >> >> the method by Bolton(~1980) is the best. Documentation of which > >> formulas > >> >> are used are essential for research as in peer-reviewed papers, you > >> must > >> >> know the formulas, and will be asked about them for the very reasons > >> >> mentioned above. Thanks in advance. > >> >> > >> >> V/R, > >> >> > >> >> Stefan > >> >> -- > >> > > >> > > >> > Stefan, > >> > > >> > I believe there is no document available for these formulas. > >> Most > >> > formulas in the IDV were created by Don in Jython or Java, and I > >> > believed he referenced those formulas in the GEMPAK. With limit > >> > resources here, it is unlikely to spend more time to create the > >> > document for these formulas. However, I can provide more details > >> > information for specific formula if the request is raised. Sorry > >> > about the inconvenience. > >> > > >> > > >> > Yuan > >> > > >> > Ticket Details > >> > =================== > >> > Ticket ID: ZEO-881615 > >> > Department: Support IDV > >> > Priority: Normal > >> > Status: Open > >> > > >> > > >> > >> > >> > > > > > > Ticket Details > > =================== > > Ticket ID: ZEO-881615 > > Department: Support IDV > > Priority: Normal > > Status: Open > > > > > > > Ticket Details =================== Ticket ID: ZEO-881615 Department: Support IDV Priority: Normal Status: Open