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Add circulation calculation #662

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@jrleeman

Calculate circulation for a cross-section.

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  1. jthielen commented on Jul 10, 2018

    @jthielen
    Collaborator

    I have a question on this as I'm working through a potential implementation:

    Going on our past assumption of implementing GEMPAK's CIRC as projected_winds (finding the vertical and cross-section-tangential components of the 3D wind), I'm not sure that this would be that practical of a function until there is some form of systematic variable recognition. This is because, right now, this function would require the user specifying DataArrays for each of the 3 wind components, and if they have those picked out, they already have the vertical, and can just use a basic tangential_component function to get the tangential component of the horizontal wind.

    So, would it be okay to put this on hold until MetPy has some kind of systematic variable identification from a xr.Dataset? Or is there a use case that I'm missing?

  2. dopplershift commented on Jul 11, 2018

    @dopplershift
    Member

    That seems reasonable to me.

  3. added
    Status: On HoldAnother issue needs resolution for this issue to proceed
    on Jul 11, 2018
  4. sgdecker commented on Aug 23, 2021

    @sgdecker
    Contributor

    What the GEMPAK CIRC function does is take omega as the vertical component (so units of Pa/s or the like) and figures out how the arrows should look so that they are parallel to the trajectory of air parcels in the plane of the cross section. I don't see an example in the gallery showing a cross section with a vertical component (https://unidata.github.io/MetPy/latest/examples/cross_section.html#sphx-glr-examples-cross-section-py has barbs with an up-down component, but that doesn't represent vertical motion), but maybe its there and I just haven't found it?

    BTW, should I open an issue requesting a declarative interface to cross sections (analogous to GDCROSS for gridded data and SNCROSS for observed soundings)?

  5. dopplershift commented on Aug 23, 2021

    @dopplershift
    Member

    There's no example using wind barbs with a vertical component. You should be able to replace u/v in the call to barbs with an appropriately scaled version of omega/w.

    Regarding GDCROSS, #1709 is what you're looking for.

  6. sgdecker commented on Aug 23, 2021

    @sgdecker
    Contributor

    OK, thanks for this and your other comment!

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    Area: CalcPertains to calculationsArea: Cross-sectionsPertains to making cross-sections through dataGEMPAK ConversionNeeded to replicate GEMPAK functionalityStatus: On HoldAnother issue needs resolution for this issue to proceed

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