Thanks for your
I spoke with my
supervisor and his suggestion solved the problem.
I used ferret to read in the World
Ocean Atlas data and filled in the land points with the @fav
command. I saved this as a new netcdf file.
I transferred the netcdf file into
python, together with the file containing the Oxygen
variable and its dimensions, and created a new variable
using those dimensions of O2 and the values of NO3
i. Python does
this step very well, as it is easy to create new variables
within an existing .nc file with existing dimensions
A new meaning
to the word PyFerret
You'll need to give Ferret more information about how the
lon/lat grid should map onto the grid that has simple indices
x=1:130 and y=1:114. Does the grid of the Oxygen data
represent a global dataset as well?
If the Oxygen grid should in fact be a global grid, then you
can redefine the coordinate axes so that they describe a
lon/lat map. For example (Here you will need to determine
what the start and end coordinates should be! This is just a
made-up example to show how it looks):
messages from Ferret warning you that redefining axes in a
dataset will alter the way Ferret treats the contents. Then
the regridding operation would do more what you expect. Again,
though, Ferret itself does not have enough information to
determine how to do the regridding automatically and so you
are intervening to make the definitions.
I notice that the Z axis has the same issues; in the first
datset it looks as if it's in meters, in the Oxygen dataset
it's simply z=1:21. You could redefine that axis as well. If
it's a depth axis use define axis/DEPTH so it will be
Note that for any of these definitions you can also define
irregularly-spaced axes by giving a list of values instead of
On 12/5/2015 9:49 PM, Pearse Buchanan
Currently using ferret v6.842.
I have a 3D matrix of nitrate
concentrations (N_AN) taken from the World Ocean Atlas 2013.
This dataset has the following grid coordinates:
I have ensured that all land points are
filled in with averages using the @fav command so that I
have a complete global dataset with no missing values where
the land might exist.
What I want to do is regrid this data,
represented in the figure on the left underneath this
paragraph, onto the same grid as my Oxygen data, represented
by the figure to the right underneath this paragraph. The
oxygen data has the following grid coordinates:
I have so far been unable to do this
because when I define a new grid, like so:
The old grid is placed onto the new grid
assuming that the new grid coordinates represent latitude
and longitude. This is the problem. Essentially, the new
grid only contains nitrate data from 0-130°E and from
0-114°N. Now, because latitudes between 90-114°N don’t
exist, there is no data for this region (Fig. below)
I’m really not sure how to fix this
problem. I want the original dataset of Nitrate[360,180,102]
to be placed within a new grid of Nitrate[130,114,21].
Thanks for any suggestions!
PhD Candidate /
CSIRO-UTAS Quantitative Marine Science
Marine and Antarctic Studies (IMAS), University of
deoxygenation: A Palaeo-Modelling Perspective” ~~~
Parts of the Ocean
are predicted to lose oxygen in the coming century. But
Looking into the
past, how does oxygen in the ocean change across climate
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