Hi,
There's a newer syntax which does the same operation as
zaxreplace function, which instead handles this as a regridding
operation. In one direction, regridding using an auxiliary
coordinate variable. This looks like:
yes? let new_var = file_var[gz(sigma)=zaxis]
Here's an FAQ about this sort of coordinate conversion. It
discusses the regridding syntax as well as the equivalent
zaxreplace function call.
https://ferret.pmel.noaa.gov/Ferret/faq/depth-axis-to-density-axis
And the general documentation about
Auxiliary Regridding
Ansley
On 2/26/2019 9:12 PM, vivek shilimkar
wrote:
Thank you all for your help.
As pointed out by Martin Schmidt, the newly defined
variable P does have four dimensions. and it is not suitable
to define an axis.
And I also understand about the auto-conversion of units is
not possible.
I am looking for way to convert the Z axis of CMIP5 model
data, which is on model grid, to standard pressure level.
I found the ZAXREPLACE(V,ZVALS,ZAX) function
in ferret may have solution to my problem.
If
you have any better and easier suggestion please let me
know.
Regards,
Vivek
Also, regarding units. Some measures of units are
automatically converted when working with coordinates; for
instance a variable with an on axis that has units of
meters can be regridded to an axis with units of meters
and Ferret/PyFerret will handle the conversion. And in the
horizontal directions, longitude/latitude are handled with
areas computed on the globe, and calendar time is
converted whether the units are seconds, days, etc. Other
units are allowed but would not be converted. So that's
all that this message about units is telling us:
*** NOTE: (fyi) units are not subject to
auto-conversion: PA
Ansley
On
2/22/2019 9:52 AM, Martin Schmidt wrote:
Dear all,
I think b*ps inherits all dimensions:
B vertical coordinate formul
... ... 1:95 ...
PS Surface Air Pressure
1:192 1:96 ... 1:120
So, p has dimension 192 x 96 x 95 x 120 and is not
suitable to define an axis.
It should be something like:
let zval = z[gz=B]
define axis/z/depth/unit="Pa" pax=zval
(depth means posive down, hopefully :-) not sure)
Best,
Martin
Am
22.02.2019 um 18:05 schrieb Satyesh Ghetiya:
Hi,
Following may give you some hints :
(1) Is pressure unit allowed ? (I think 'K'
means only depth is allowed in distance unit )
(2) In _expression_ "let P = ap+(b*ps)" . b*ps is
'missing data' everywhere. Because there are no
common valid points in 3 D which can give answer.
(missing data * good data = "" data)
^ This may not solve problem , but will give you
path to solve.
Regards,
Satyesh
Dear all,
I have been trying to define new vertical
axis for my data.
However, I am getting following error in
ferret.
AP vertical coordinate formul
... ... 1:95
...
B vertical coordinate formul
... ... 1:95
...
PS Surface Air Pressure
1:192 1:96 ...
1:120
AP_BNDS vertical coordinate formul
1:2 ... 1:95 ...
B_BNDS vertical coordinate formul
1:2 ... 1:95 ...
CL Cloud Area Fraction
1:192 1:96 1:95
1:120
define axis/from_data/z/unit="Pa"
pressure_axis=P[k=1:95]
*** NOTE: (fyi) units are
not subject to auto-conversion: PA
**ERROR: improper grid or axis
definition: data for DEFINE
AXIS/FROM_VARIABLE is ambiguous
define axis/from_data/z/unit="Pa"
pressure_axis=P[k=1:95]
Command file, command group, or
REPEAT execution aborted
Am I doing it right way? Or is it not
possible to define axis this way?
Regards,
Vivek
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