Useful Tools
Climate Data Operators (CDO)
As stated by their creators, the Data Operators (CDO) are:
CDO is a collection of command line Operators to manipulate and analyse Climate and NWP model Data.
Note that for
Possible example uses of CDO are:
Display info about a file
CDO offers many operators that provide information about a file. The most important two are infon and sinfon. Note the n at the end: that means "display variable names". If you don't provide that, you'll still get information, but it'll be for variables -1, -2, -3, etc.
Short Information
If you just want a summary of what's in the file, use sinfon:
$ cdo sinfon stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4
File format: netCDF4
-1 : Institut Source Ttype Levels Num Gridsize Num Dtype : Parameter name
1 : unknown unknown instant 48 1 16380 1 F32 : CLCN
2 : unknown unknown instant 48 1 16380 1 F32 : CLLS
3 : unknown unknown instant 48 1 16380 1 F32 : CNVMF0
4 : unknown unknown instant 48 1 16380 1 F32 : CNVMFC
5 : unknown unknown instant 48 1 16380 1 F32 : CNVMFD
6 : unknown unknown instant 48 1 16380 1 F32 : EVAPC
7 : unknown unknown instant 48 1 16380 1 F32 : FCLD
8 : unknown unknown instant 1 2 16380 1 F32 : PHIS
9 : unknown unknown instant 48 1 16380 1 F32 : QI
10 : unknown unknown instant 48 1 16380 1 F32 : QICN
11 : unknown unknown instant 48 1 16380 1 F32 : QILS
12 : unknown unknown instant 48 1 16380 1 F32 : QL
13 : unknown unknown instant 48 1 16380 1 F32 : QLCN
14 : unknown unknown instant 48 1 16380 1 F32 : QLLS
15 : unknown unknown instant 48 1 16380 1 F32 : QR
16 : unknown unknown instant 48 1 16380 1 F32 : REVAN
17 : unknown unknown instant 48 1 16380 1 F32 : REVCN
18 : unknown unknown instant 48 1 16380 1 F32 : REVLS
19 : unknown unknown instant 48 1 16380 1 F32 : RH1
20 : unknown unknown instant 48 1 16380 1 F32 : RICE
21 : unknown unknown instant 48 1 16380 1 F32 : RLIQ
22 : unknown unknown instant 48 1 16380 1 F32 : RSUAN
23 : unknown unknown instant 48 1 16380 1 F32 : RSUCN
24 : unknown unknown instant 48 1 16380 1 F32 : RSULS
25 : unknown unknown instant 48 1 16380 1 F32 : SUBLC
26 : unknown unknown instant 48 1 16380 1 F32 : THIM
Grid coordinates :
1 : lonlat > size : dim = 16380 nlon = 180 nlat = 91
lon : first = -180 last = 178 inc = 2 degrees_east circular
lat : first = -90 last = 90 inc = 2 degrees_north
Vertical coordinates :
1 : pressure hPa : 1000 975 950 925 900 875 850 825 800 775 750 725
700 650 600 550 500 450 400 350 300 250 200 150
100 70 50 40 30 20 10 7 5 4 3 2 1 0.699999988 0.5
0.400000006 0.300000012 0.200000003 0.100000001
0.0700000003 0.0500000007 0.0399999991 0.0299999993
0.0199999996
2 : surface : 0
Time coordinate : 1 step
RefTime = 2000-04-15 09:00:00 Units = minutes Calendar = STANDARD
YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss
2000-04-15 09:00:00
cdo sinfon: Processed 26 variables over 1 timestep ( 0.02s )
Information and Simple Statistics
The other operator, infon, provides more information and some useful statistics:
$ cdo infon stock-G40U-Intel11-2013Jun10-1day-c48.geosgcm_moist.20000415_0900z.nc4
-1 : Date Time Level Gridsize Miss : Minimum Mean Maximum : Parameter name
1 : 2000-04-15 09:00:00 1000 16380 7283 : 0.0000 0.00055663 0.053927 : CLCN
2 : 2000-04-15 09:00:00 975 16380 3443 : 0.0000 0.0053316 0.19191 : CLCN
3 : 2000-04-15 09:00:00 950 16380 2381 : 0.0000 0.021698 0.52759 : CLCN
4 : 2000-04-15 09:00:00 925 16380 2008 : 0.0000 0.046928 0.62649 : CLCN
5 : 2000-04-15 09:00:00 900 16380 1730 : 0.0000 0.068160 0.76086 : CLCN
6 : 2000-04-15 09:00:00 875 16380 1488 : 0.0000 0.083106 0.78922 : CLCN
7 : 2000-04-15 09:00:00 850 16380 1340 : 0.0000 0.082435 0.85127 : CLCN
8 : 2000-04-15 09:00:00 825 16380 1216 : 0.0000 0.064390 0.79455 : CLCN
9 : 2000-04-15 09:00:00 800 16380 1135 : 0.0000 0.049025 0.67987 : CLCN
10 : 2000-04-15 09:00:00 775 16380 1024 : 0.0000 0.039010 0.71728 : CLCN
11 : 2000-04-15 09:00:00 750 16380 927 : 0.0000 0.033034 0.67065 : CLCN
12 : 2000-04-15 09:00:00 725 16380 800 : 0.0000 0.028919 0.82533 : CLCN
13 : 2000-04-15 09:00:00 700 16380 680 : 0.0000 0.025265 0.71002 : CLCN
14 : 2000-04-15 09:00:00 650 16380 161 : 0.0000 0.023027 0.60691 : CLCN
15 : 2000-04-15 09:00:00 600 16380 21 : 0.0000 0.029113 0.79990 : CLCN
16 : 2000-04-15 09:00:00 550 16380 2 : 0.0000 0.031865 0.86731 : CLCN
17 : 2000-04-15 09:00:00 500 16380 0 : 0.0000 0.021714 0.86754 : CLCN
18 : 2000-04-15 09:00:00 450 16380 0 : 0.0000 0.016821 0.80432 : CLCN
19 : 2000-04-15 09:00:00 400 16380 0 : 0.0000 0.017517 0.82690 : CLCN
20 : 2000-04-15 09:00:00 350 16380 0 : 0.0000 0.029577 0.84485 : CLCN
21 : 2000-04-15 09:00:00 300 16380 0 : 0.0000 0.037508 0.84544 : CLCN
22 : 2000-04-15 09:00:00 250 16380 0 : 0.0000 0.048294 0.80001 : CLCN
23 : 2000-04-15 09:00:00 200 16380 0 : 0.0000 0.053185 0.77885 : CLCN
24 : 2000-04-15 09:00:00 150 16380 0 : 0.0000 0.035487 0.83891 : CLCN
25 : 2000-04-15 09:00:00 100 16380 0 : 0.0000 0.00044752 0.19931 : CLCN
26 : 2000-04-15 09:00:00 70 16380 0 : 0.0000 0.0000 0.0000 : CLCN
27 : 2000-04-15 09:00:00 50 16380 0 : 0.0000 0.0000 0.0000 : CLCN
28 : 2000-04-15 09:00:00 40 16380 0 : 0.0000 0.0000 0.0000 : CLCN
29 : 2000-04-15 09:00:00 30 16380 0 : 0.0000 0.0000 0.0000 : CLCN
30 : 2000-04-15 09:00:00 20 16380 0 : 0.0000 0.0000 0.0000 : CLCN
31 : 2000-04-15 09:00:00 10 16380 0 : 0.0000 0.0000 0.0000 : CLCN
32 : 2000-04-15 09:00:00 7 16380 0 : 0.0000 0.0000 0.0000 : CLCN
33 : 2000-04-15 09:00:00 5 16380 0 : 0.0000 0.0000 0.0000 : CLCN
34 : 2000-04-15 09:00:00 4 16380 0 : 0.0000 0.0000 0.0000 : CLCN
35 : 2000-04-15 09:00:00 3 16380 0 : 0.0000 0.0000 0.0000 : CLCN
36 : 2000-04-15 09:00:00 2 16380 0 : 0.0000 0.0000 0.0000 : CLCN
37 : 2000-04-15 09:00:00 1 16380 0 : 0.0000 0.0000 0.0000 : CLCN
38 : 2000-04-15 09:00:00 0.7 16380 0 : 0.0000 0.0000 0.0000 : CLCN
39 : 2000-04-15 09:00:00 0.5 16380 0 : 0.0000 0.0000 0.0000 : CLCN
40 : 2000-04-15 09:00:00 0.4 16380 0 : 0.0000 0.0000 0.0000 : CLCN
41 : 2000-04-15 09:00:00 0.3 16380 0 : 0.0000 0.0000 0.0000 : CLCN
42 : 2000-04-15 09:00:00 0.2 16380 0 : 0.0000 0.0000 0.0000 : CLCN
43 : 2000-04-15 09:00:00 0.1 16380 0 : 0.0000 0.0000 0.0000 : CLCN
44 : 2000-04-15 09:00:00 0.07 16380 0 : 0.0000 0.0000 0.0000 : CLCN
45 : 2000-04-15 09:00:00 0.05 16380 0 : 0.0000 0.0000 0.0000 : CLCN
46 : 2000-04-15 09:00:00 0.04 16380 0 : 0.0000 0.0000 0.0000 : CLCN
47 : 2000-04-15 09:00:00 0.03 16380 0 : 0.0000 0.0000 0.0000 : CLCN
48 : 2000-04-15 09:00:00 0.02 16380 0 : 0.0000 0.0000 0.0000 : CLCN
49 : 2000-04-15 09:00:00 1000 16380 7283 : 0.0000 0.019079 0.97125 : CLLS
50 : 2000-04-15 09:00:00 975 16380 3443 : 0.0000 0.068198 0.94812 : CLLS
51 : 2000-04-15 09:00:00 950 16380 2381 : 0.0000 0.083635 0.93380 : CLLS
52 : 2000-04-15 09:00:00 925 16380 2008 : 0.0000 0.096190 0.83637 : CLLS
...
As you can see, you not only get information, but statistics. It provides the number of values on the grid, Gridsize; the number of Missing Values, Miss; and the Minimum, Mean, and Maximum for each Level for each value.
Diff two files
Extract variable(s) from a file
Extract time(s) from a file
To extract a single (or multiple) year from a multi-step file, you can use selyear,year. For multiple years, you can either do cdo selyear,1999,2000,2001 or cdo selyear,1999/2001.
$ cdo sinfon pchem.species.CMIP-5.1870-2097.z_91x72.nc4
File format: netCDF4
-1 : Institut Source Ttype Levels Num Gridsize Num Dtype : Parameter name
1 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : OX
2 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : N2O
3 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : CFC11
4 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : CFC12
5 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : CH4
6 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : HCFC22
7 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : H2O
Grid coordinates :
1 : lonlat > size : dim = 91 nx = 0 ny = 91
lat : first = -1.57079637 last = 1.57079625 inc = 0.0349065065 radians
Vertical coordinates :
1 : generic layer : 1.5 2.63499999 4.01500034 5.67999983 7.76499939
10.4499998 13.960001 18.5400009 24.4899979 32.1749992
42.0400009 54.6300011 70.5950012 90.7249985 115.995003
147.565002 186.790009 235.26001 294.829987 367.649994
456.169983 563.179993 691.830017 845.63501 1028.49011
1246.01501 1505.02502 1812.43494 2176.09985 2604.90991
3108.89014 3699.26978 4390.96533 5201.58984 6149.56494
7255.78467 8543.89941 10051.4355 11825 13911.501
16366.1504 19254.0977 22651.3496 26647.9004 31279.1504
35625 39375 43125 46875 50625 54375 58125 61875
65625 69375 73125.0156 76250 78750 81250.0156 83750.0156
85750.0156 87250.0078 88750 90249.9844 91749.9844
93250.0078 94750 96249.9766 97374.9766 98124.9922
98875 99625
Time coordinate : 2736 steps
RefTime = 1870-01-15 12:00:00 Units = hours Calendar = standard
YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss
1870-01-15 12:00:00 1870-02-14 22:00:00 1870-03-17 08:00:00 1870-04-16 18:00:00
1870-05-17 04:00:00 1870-06-16 14:00:00 1870-07-17 00:00:00 1870-08-16 10:00:00
1870-09-15 20:00:00 1870-10-16 06:00:00 1870-11-15 16:00:00 1870-12-16 02:00:00
1871-01-15 12:00:00 1871-02-14 22:00:00 1871-03-17 08:00:00 1871-04-16 18:00:00
...snip...
2096-07-21 20:00:00 2096-08-21 06:00:00 2096-09-20 16:00:00 2096-10-21 02:00:00
2096-11-20 12:00:00 2096-12-20 22:00:00 2097-01-20 08:00:00 2097-02-19 18:00:00
2097-03-22 04:00:00 2097-04-21 14:00:00 2097-05-22 00:00:00 2097-06-21 10:00:00
2097-07-21 20:00:00 2097-08-21 06:00:00 2097-09-20 16:00:00 2097-10-21 02:00:00
cdo sinfon: Processed 7 variables over 2736 timesteps ( 0.11s )
$ cdo selyear,1999,2000,2001 pchem.species.CMIP-5.1870-2097.z_91x72.nc4 ~/test.nc4
cdo selyear: Processed 1651104 values from 7 variables over 2736 timesteps ( 0.73s )
$ cdo sinfon ~/test.nc4
File format: netCDF4
-1 : Institut Source Ttype Levels Num Gridsize Num Dtype : Parameter name
1 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : OX
2 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : N2O
3 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : CFC11
4 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : CFC12
5 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : CH4
6 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : HCFC22
7 : unknown http://geos5.org/wiki/index.php?title=GEOS-5_Configuration_for_AR5 instant 72 1 91 1 F32 : H2O
Grid coordinates :
1 : lonlat > size : dim = 91 nx = 0 ny = 91
lat : first = -1.57079637 last = 1.57079625 inc = 0.0349065065 radians
Vertical coordinates :
1 : generic layer : 1.5 2.63499999 4.01500034 5.67999983 7.76499939
10.4499998 13.960001 18.5400009 24.4899979 32.1749992
42.0400009 54.6300011 70.5950012 90.7249985 115.995003
147.565002 186.790009 235.26001 294.829987 367.649994
456.169983 563.179993 691.830017 845.63501 1028.49011
1246.01501 1505.02502 1812.43494 2176.09985 2604.90991
3108.89014 3699.26978 4390.96533 5201.58984 6149.56494
7255.78467 8543.89941 10051.4355 11825 13911.501
16366.1504 19254.0977 22651.3496 26647.9004 31279.1504
35625 39375 43125 46875 50625 54375 58125 61875
65625 69375 73125.0156 76250 78750 81250.0156 83750.0156
85750.0156 87250.0078 88750 90249.9844 91749.9844
93250.0078 94750 96249.9766 97374.9766 98124.9922
98875 99625
Time coordinate : 36 steps
RefTime = 1870-01-15 12:00:00 Units = hours Calendar = standard
YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss
1999-01-14 22:00:00 1999-02-14 08:00:00 1999-03-16 18:00:00 1999-04-16 04:00:00
1999-05-16 14:00:00 1999-06-16 00:00:00 1999-07-16 10:00:00 1999-08-15 20:00:00
1999-09-15 06:00:00 1999-10-15 16:00:00 1999-11-15 02:00:00 1999-12-15 12:00:00
2000-01-14 22:00:00 2000-02-14 08:00:00 2000-03-15 18:00:00 2000-04-15 04:00:00
2000-05-15 14:00:00 2000-06-15 00:00:00 2000-07-15 10:00:00 2000-08-14 20:00:00
2000-09-14 06:00:00 2000-10-14 16:00:00 2000-11-14 02:00:00 2000-12-14 12:00:00
2001-01-13 22:00:00 2001-02-13 08:00:00 2001-03-15 18:00:00 2001-04-15 04:00:00
2001-05-15 14:00:00 2001-06-15 00:00:00 2001-07-15 10:00:00 2001-08-14 20:00:00
2001-09-14 06:00:00 2001-10-14 16:00:00 2001-11-14 02:00:00 2001-12-14 12:00:00
cdo sinfon: Processed 7 variables over 36 timesteps ( 0.00s )