[Feature]: Consider adding vertical regridding feature to reconstruct pressure from hybrid #446
Comments
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Hey @jasonb5, can you follow the "Describe the solution you'd like" and see what we should do?
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@tomvothecoder I'll check this out and see if I can find anything existing otherwise I'll go off the original plan I had for this in #388. |
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Thanks @jasonb5! |
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I would happily merge this in cf-xarray. We already support a few ocean parametric coordinates. The code would go here https://github.com/xarray-contrib/cf-xarray/blob/c36a3687b3820176c394580f86a67ca53b9cadbd/cf_xarray/accessor.py#L2507 |
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Hey @dcherian, yes @jasonb5 came across that feature in cf-xarray! He mentioned it might be a good opportunity to make a PR to cf-xarray to support decoding other parametric vertical coordinates. Ideally, we'd like to have this feature out relatively soon so we can start refactoring some other packages with it. |
Yes, at the moment I just release when there's some nice new feature. |
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Hey @jasonb5 and @chengzhuzhang, I found these features from
Also MetPy has the |
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In testing
This is a clunky function (though it so far appears to be working on CMIP data...). I am absolutely sure you developers can come up with a better method for interpreting the hybrid formula on the fly, but I thought I'd put it here in case it is useful. I also recognize using def interprete_formula(f):
operator_chars = ['*', '(', ')', '+', '-', '/']
# first find/remove all parenthesis that are specifying axes
# p(n,k,j,i) = ap(k) + b(k)*ps(n,j,i) --> p = ap + b*ps
# get formula indices corresponding to a left hand parenthesis (
pinds = [i for i in range(len(f)) if f[i] == '(']
# initialize list to replace sections of formula (e.g., '(i,j,k)' --> '')
replace = []
# loop over left hand parenthesis instances
for p in pinds:
pref = '' # initialize parenthesis string
stopsearch = False # set stop flag to false
# loop from left hand parentheis to end of formula
for i in range(p, len(f)):
# if stopsearch, continue
if stopsearch:
continue
# get indexed character
c = f[i]
# check for close parenthesis )
# if closed, stopsearch
if c == ')':
pref += c # add character to parenthesis string
stopsearch = True
else:
pref += c # add character to parenthesis string
# check for arithmetic operators inside parenthesis string
ocs = [c for c in pref[1:-1] if c in operator_chars]
# if no arithmetic operators, queue parenthesis string for removal
if len(ocs) == 0:
replace.append(pref)
# remove all parenthesis strings with no arithmetic operators
for r in replace:
f = f.replace(r, '')
# further process formula
fout = '' # initialize blank formula
vid = '' # initialize blank variable
lhs = f.split('=')[0] # get lhs
f = f.split('=')[1] # get rhs
# loop over each char
for s in f:
# ignore blank spaces
if s == ' ':
continue
# if arithmetic operator, need to add to formula
if s in operator_chars:
# if a variable is not empty, write it out first
if len(vid) > 0:
fout = fout + 'ds["' + vid + '"]'
vid = '' # reset variable accumulator
# write out arithmetic operator
fout = fout + s
else:
# char must be part of a variable - add to variable accumulator
vid += s
# finished looping over all characters
# write out variable to formula
fout = fout + 'ds["' + vid + '"]'
# add lhs
fout = lhs + ' = ' + fout
# return formula
return fout |
tomvothecoder
modified the milestones:
FY24Q1 (10/01/23 - 12/31/23),
FY24Q2 (01/01/24 - 03/31/24)
tomvothecoder
modified the milestones:
FY24Q1 (10/01/23 - 12/31/23),
FY24Q2 (01/01/24 - 03/31/24)
tomvothecoder
modified the milestones:
FY24Q2 (01/01/24 - 03/31/24),
FY24Q3 (4/01/24 - 06/30/24)
tomvothecoder
modified the milestones:
FY24 Items to Work On,
FY24Q3 (4/01/24 - 06/30/24)
tomvothecoder
modified the milestones:
FY24Q3 (4/01/24 - 06/30/24),
FY24Q4 (07/01/24 - 09/30/24)
tomvothecoder
modified the milestones:
FY24Q3 (4/01/24 - 06/30/24),
FY24Q4 (07/01/24 - 09/30/24)
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@pochedls @tomvothecoder Created PR in the cf_xarray repo xarray-contrib/cf-xarray#528. |
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I think I have this started correctly. @jasonb5 – would I pulled your PR (in my normal xcdat environment) import cf-xarray and Syntax for testers (i.e., note to self): |
SummaryI made some progress on this. The main finding is that models with the formula I've broken the problem into two main chunks ("Decode Error" and "Silent Failures"): Decode ErrorThe following models produce an error ( UKESM* and HadGEM3-GC31-LL produce Silent failuresA number of models silently fail (i.e., CESM2-WACCM and CESM2 also silently fail with IPSL-CM6A-LR also silently fails. It has vertical coordinate presnivs with Dataset ListingsDatasets with no apparent problem
Dataset with an error on
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Now that is amazing. Given
perhaps we can check units to decide which representation to use. |
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FYI – I had focused on testing atmospheric vertical coordinates. Ideally we could get some help testing ocean coordinates (@durack1?); otherwise, this might take awhile to stress test. Although I think CMIP data I've used is mostly on depth coordinates: are there CMIP ocean variables that are typically on coordinate systems that would need to be "decoded" (ocean sigma, s-coordinate, etc.)? |
tomvothecoder
modified the milestones:
FY24Q4 (07/01/24 - 09/30/24),
FY25Q1 (10/01/24 - 12/31/24)
Is your feature request related to a problem?
Related to #45 and #388.
Discussed in #440
Originally posted by tomvothecoder March 27, 2023
Hi @xCDAT/core-developers or anybody in the xCDAT community. Have any of you come across a package that implements an xarray-based function similar to
cdutil.vertical.reconstructPressureFromHybrid? I am working on refactoringe3sm_diagsande3sm_to_cmipto use xarray/xCDAT and there are references to this function that I need to replace. Thanks!Docstring:
Examples Usages:
Describe the solution you'd like
First, check of any other xarray-based package includes this feature.
cdutil.vertical.reconstructPressureFromHybrid)Describe alternatives you've considered
No response
Additional context
No response
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