# regrid Coupled Model Intercomparison Project 3 (CMIP 3) data

From: Anandhi Aavudai <AavudaiA_at_nyahnyahspammersnyahnyah>
Date: Sat, 3 Oct 2009 23:07:40 -0400

Hi,

I would like to regrid the daily data from the various AOGCMs in Coupled Model Intercomparison Project 3 (CMIP 3) having different gausian grids to a common grid at every 2.5 deg lat & 2.5 deg lon.

My sample program for regriding 1 AOGCM is

begin
;=========================================;
; step 1: read netcdf file
;=========================================;

orig = in->pr
time = in->time
lat = in->lat
lon = in->lon
;=========================================;
; interpolate to new grid
;=========================================;
newgrid = g2fsh_Wrap(orig,(/72,144/))
printVarSummary(newgrid)
print(lat)
end

Some questions in this regard

1. Is "g2fsh_Wrap" the appropriate function for this purpose?
2. If answer to question 1 is yes, the numbers 72 & 144 did not give me the regridded values at every 2.5 deg lat & lon (lat = -87.5,-85,....85, 87.5)
i obtained the numbers : 72 by dividing (all lat) 180 by 2.5;
144 by dividing (all lon) 360 by 2.5;

printing the summary of newgrid
printVarSummary(newgrid) gave me these results

Variable: newgrid
Type: float
Total Size: 151455744 bytes
37863936 values
Number of Dimensions: 3
Dimensions and sizes: [time | 3652] x [lat | 72] x [lon | 144]
Coordinates:
time: [58804.5..62455.5]
lat: [-90..90]
lon: [ 0..357.5]
Number Of Attributes: 7
long_name : Accumulated Total Precipitation
original_units : mm/day
units : kg m-2 s-1
missing_value : 1e+20
_FillValue : 1e+20
cell_methods : time: mean (interval: 30 minutes)
standard_name : precipitation_flux
-------printing lat---
print(lat) gave--
Variable: lat
Type: double
Total Size: 512 bytes
64 values
Number of Dimensions: 1
Dimensions and sizes: [lat | 64]
Coordinates:
lat: [-87.86380004999999..87.86380004999999]
Number Of Attributes: 5
long_name : Latitude
standard_name : latitude
axis : Y
units : degrees_north
bounds : lat_bnds
(0) -87.86380004999999
(1) -85.0965271
(2) -82.31291199
(3) -79.52560425
(4) -76.73690033
(5) -73.9475174
(6) -71.15775299000001
(7) -68.36775969999999

3. why did print(lat) not give fixed grid values at 2.5 degree spacing in latitudes? Are lat array values (printed above) represent the latitude values before the file is regridded?
4. how to access the values of 72 latitudes & 144 longitudes of newgrid array?

Thanks in advance for the help.

regards
anandhi
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Received on Sat Oct 03 2009 - 21:07:40 MDT

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