[aspect-devel] temperature anomaly postprocessor

[Max Rudolph]

All,
I want to be able to be able to output the temperature anomaly
(temperature-average temperature at this depth). It looks like there are
some postprocessors that do similar things but nothing exactly like this.
For instance, the temperature-adiabatic temperature is similar, but not
applicable to an incompressible model, and only of limited relevance to
understanding the buoyancy structure in a compressible model. I do not see
a way to do this in VisIt either. Please let me know if this functionality
already exists!

I have a question about how to implement such a postprocessor. I think that
what I need to do is first calculate a depth-averaged temperature (similar
to the calculation of depth-averaged Vs in seismic anomalies.cc) and then
calculate and subtract the depth-average value from each temperature value.

If I make a new postprocessor that inherits from DataPostprocessorScalar,
my understanding is that evaluate_vector_field gets called on each cell, so
if I call get_lateral_averaging().get_temperature_averages() from within
this function, the code will be exceedingly slow as the depth averages
would be re-calculated for every cell. The only way that I can see to get
around this would be to calculate the depth-averaged temperature once in
the 'Initialize' method of my postprocessor. Do postprocessors get
re-initialized each timestep? If not, this would not work.

The other possibility seems to be to write something that inherits from
SimulatorAccess and CellDataVectorCreator, but then I will only get an
average temperature for each cell, which is not what I would prefer. Is
there something like CellDataVectorCreator that works with nodal values
instead of cell-centered values?

Thank you for any guidance that you can provide on this.

Max
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