[gradsusr] MODIS DATA

[Joshua Ngaina]

 Dear GrADs Users,


 I am trying to extract MODIS aerosol product (AOD at 0.550 microns). These
file has no discernable time coordinate -- using default values. If I
display the contents of the file, I get something. I also can get a value
for specific grids. I have written a descriptor file to define my time
dimension and also combine the different files. This, I have successfully
done. However, if I try to display the contents, I get the error. Again if
I try to write the contents of the file to a text file, all the values
printed are missing.


 Kindly advise


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ga-> sdfopen
MOD08_M3.A2000061.051.2010273213159.pscs_000500501908.Optical_Depth_Land_And_Ocean_Mean_Mean.G3.nc

Scanning self-describing file:
MOD08_M3.A2000061.051.2010273213159.pscs_000500501908.Optical_Depth_Land_And_Ocean_Mean_Mean.G3.nc

SDF file has no discernable time coordinate -- using default values.

SDF file
MOD08_M3.A2000061.051.2010273213159.pscs_000500501908.Optical_Depth_Land_And_Ocean_Mean_Mean.G3.ncis
open as file 1

LON set to 0 360

LAT set to -89.5 89.5

LEV set to 0 0

Time values set: 1:1:1:0 1:1:1:0

E set to 1 1

 ga-> d optical_depth_l

Contouring: -0 to 5 interval 0.5

  ga-> open jos-all.ctl

Scanning description file: jos-all.ctl

Data file MOD08_M3.A20%y2%
mc.051.2010280204610.pscs_000500502115.Optical_Depth_Land_And_Ocean_Mean_Mean.G3.ncis
open as file 1

LON set to 0 360

LAT set to -89.5 89.5

LEV set to 0 0

Time values set: 2000:3:1:0 2000:3:1:0

E set to 1 1

 I checked the current dimension by

ga-> q dims

Default file number is: 1

X is varying Lon = 0 to 360 X = 180.5 to 540.5

Y is varying Lat = -89.5 to 89.5 Y = 1 to 180

Z is fixed Lev = 0 Z = 1

T is fixed Time = 00Z01MAR2000 T = 1

E is fixed Ens = 1 E = 1

 these are the content of my descriptor file

ga-> q ctlinfo

dset MOD08_M3.A20%y2%
mc.051.2010280204610.pscs_000500502115.Optical_Depth_Land_And_Ocean_Mean_Mean.G3.nc

title "MODIS Aerosol Optical Thickness"

undef -9999

dtype netcdf

xdef 360 linear -179.5 1

ydef 180 linear -89.5 1

zdef 1 linear 0 1

tdef 159 linear 00Z01MAR2000 1mo

vars 1

optical_depth_l 0 y,x Aerosol Optical Thickness at 0.55 microns for both
Ocean (best) and Land (corrected): Mean of Daily Mean

endvars

 I set t =1 and try to display and I get an error

 ga-> set t 1

Time values set: 2000:3:1:0 2000:3:1:0

ga-> d optical_depth_l

Cannot contour grid - all undefined values

 ga-> q dims

Default file number is: 1

X is fixed Lon = 30.5 X = 211

Y is fixed Lat = 1.5 Y = 92

Z is fixed Lev = 0 Z = 1

T is varying Time = 00Z01JAN0001 to 02:38Z01JAN0001 T = 1 to 159

E is fixed Ens = 1 E = 1


 ga-> fprintf optical_depth_l modis.txt

wrote 159 values to file "modis.txt"

159 -9.99e+08 ga->

=======================================================================


Regards

Joshua
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