From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>

Date: Sat, 29 Apr 2006 19:18:11 -0600 (MDT)

Date: Sat, 29 Apr 2006 19:18:11 -0600 (MDT)

*> I am wondering if there is a function, built-in or contributed,
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*> which can be used to calculate the advection of a given
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*> variable, like ECMWF or NCEP temperature, in NCL?
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I assume you mean:

u*(dT/dx) + v*(dT/dy)

--- If the data are global then use spherical harmonic functions to compute the gradients. gaussian grid: http://www.ncl.ucar.edu/Document/Functions/Built-in/gradsg.shtml regular [fixed] grid: http://www.ncl.ucar.edu/Document/Functions/Built-in/gradsf.shtml --- If the grid has missing data or is limited area then you can use "center_finite_dif" if you have a regular grid. The grid points need not be equally spaced. http://www.ncl.ucar.edu/Document/Functions/Built-in/center_finite_diff.shtml Example 6 shows how to compute dT/dx ; you can use the same process for latitude dT/dy. --- Godd luck D _______________________________________________ ncl-talk mailing list ncl-talk_at_ucar.edu http://mailman.ucar.edu/mailman/listinfo/ncl-talkReceived on Sat Apr 29 2006 - 19:18:11 MDT

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