CDO

hi Kendy!

1) I dont know, what kind of values you expect to be there for each day out for a 5-day-mean. Constant? linear interpolation?

2) There are all kinds of seasonal operators - check the list with running

cdo -h seas

hth
ralf

Hi, Ralf Mueller
Firstly, thanks for your feedback.
Now, responding your question:

1. I would like to get daily values from that 5-day-mean and I guess for that should be used linear interpolation, is not it, Ralf Mueller?

Thanks

Silverio

AFAIK there is no such thing as interpolation along the time-axis in CDO.

sry
ralf

Hi Silverio,

may I make a remark here. Time interpolation from 5-daily (pentad) values to 1-daily values can be done using the inttime operator.

cdo inttime,1979-01-01,00:00:00,1day precip.pentad.mean.nc precip.daily.mean.nc

-Karin

awesome - didnt know about that operator,yet ;-)

thx @Karin

Hi, Karin
It worked perfectly.
Thank you very.

By the way, is there any suggestion for converting netcdf (.nc) data to binary (.ctl)?

Cheers,

Silverio

If you want to use GrADS you don't need to convert netCDF files, GrADS can read them. See http://cola.gmu.edu/grads/gadoc/SDFdescriptorfile.html

But of course CDO can create a .ctl file (which is not a binary file) using the gradsdes operator:

cdo gradsdes your_file.nc

The name of the .ctl file will be your_file.ctl in the same data directory.

-Karin

Dear Karin, I am trying to do as the operator suggest (cdo gradsdes precip.daily.mean.nc), but I am getting error (cdo gradsdes (Abort): Unsupported file format!). Any idea?

Tks,

Silverio

Without your data it is not possible to say what is going wrong. Which CDO version (cdo -V) are you using? Can you send us the output of the ncdump call or the file itself?

ncdump -h precip.daily.mean.nc

-Karin

The data I am using is from https://www.esrl.noaa.gov/psd/data/gridded/data.cmap.html, which through the command cdo inttime,1979-01-01,00:00:00,1day precip.pentad.mean.nc I got daily data (precip.daily.mean.nc) and then I tried to use cdo gradsdes your_file.nc to get .ctl data, but I am experiencing this issue (cdo gradsdes (Abort): Unsupported file format!) as I have reported you.

From ncdump -h precip.daily.mean.nc I get it:

netcdf precip.daily.mean {
dimensions:
lon = 144 ;
lat = 72 ;
time = UNLIMITED ; // (13876 currently)
variables:
float lon(lon) ;
lon:standard_name = "longitude" ;
lon:long_name = "Longitude" ;
lon:units = "degrees_east" ;
lon:axis = "X" ;
float lat(lat) ;
lat:standard_name = "latitude" ;
lat:long_name = "Latitude" ;
lat:units = "degrees_north" ;
lat:axis = "Y" ;
double time(time) ;
time:standard_name = "time" ;
time:long_name = "Time" ;
time:units = "hours since 1800-1-1 00:00:00" ;
time:calendar = "standard" ;
time:axis = "T" ;
float precip(time, lat, lon) ;
precip:long_name = "Average Pentad Rate of Precipitation" ;
precip:units = "mm/day" ;
precip:_FillValue = -9.96921e+36f ;
precip:missing_value = -9.96921e+36f ;
precip:precision = 2s ;
precip:least_significant_digit = 2s ;
precip:var_desc = "Precipitation" ;
precip:dataset = "CPC Merged Analysis of Precipitation Standard" ;
precip:level_desc = "Surface" ;
precip:statistic = "Pentad Mean" ;
precip:parent_stat = "Mean" ;
precip:actual_range = 0.f, 209.67f ;

// global attributes:
:CDI = "Climate Data Interface version ?? (http://mpimet.mpg.de/cdi)" ;
:history = "Fri Jul 13 13:19:46 2018: cdo inttime,1979-01-01,00:00:00,1day precip.pentad.mean.nc precip.daily.mean.nc\n",
"update 03/2017 V1701" ;
:source = "ftp ftp.cpc.ncep.noaa.gov precip/cmap/pentad" ;
:Conventions = "COARDS" ;
:title = "CPC Merged Analysis of Precipitation Pentad data (excludes NCEP Reanalysis I)" ;
:platform = "Analyses" ;
:hisotry = "Converted to chunked, deflated non-packed NetCDF4 Jul 2014" ;
:dataset_title = "CPC Merged Analysis of Precipitation" ;
:documentation = "https://www.esrl.noaa.gov/psd/data/gridded/data.cmap.html" ;
:References = "https://www.esrl.noaa.gov/psd/data/gridded/data.cmap.html" ;
:version = "V1701" ;
:Version = "V1701" ;
:CDO = "Climate Data Operators version 1.7.0 (http://mpimet.mpg.de/cdo)" ;
}

To get the version, version (cdo -V) I have got this info:

Data Operators version 1.7.0 (http://mpimet.mpg.de/cdo)
Compiler: gcc -g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wall -pedantic -fPIC -fopenmp 
 version: gcc (Ubuntu 5.3.1-9ubuntu2) 5.3.1 20160220
Features: DATA PTHREADS OpenMP4 HDF5 NC4/HDF5/threadsafe OPeNDAP SZ Z UDUNITS2 PROJ.4 MAGICS CURL FFTW3 SSE2
Libraries: HDF5/1.8.16 proj/4.92 curl/7.47.0
Filetypes: srv ext ieg grb grb2 nc nc2 nc4 nc4c 
     CDI library version : 1.7.0
GRIB_API library version : 1.14.4
  netCDF library version : 4.4.0 of Mar 29 2016 11:41:40 $
    HDF5 library version : 1.8.16
 SERVICE library version : 1.4.0
   EXTRA library version : 1.4.0
     IEG library version : 1.4.0
    FILE library version : 1.8.2

I am trying to convert the data to compute composite analysis, whose initial data should be in .ctl and .bin.

Thank you Mr. Karin in advance for your help.

Ok, you are using an old CDO version which maybe cause the problems. Please, update to the current version.

Here is what I did with the data:

cdo inttime,1979-01-01,00:00:00,1day precip.pentad.mean.nc out_time_interpolate.nc
cdo gradsdes out_time_interpolate.nc

* Generated by CDO operator gradsdes
*
DSET  ^out_time_interpolate.nc
DTYPE  NetCDF
XDEF 144 LINEAR 1.250000 2.500000
YDEF 72 LINEAR -88.750000 2.500000
ZDEF 1 LEVELS 0 
TDEF 13876 LINEAR 00:00Z01jan1979 1dy
TITLE  out_time_interpolate.nc  144x72 grid
OPTIONS yrev
UNDEF  -9.96921e+36
VARS  1
precip             0  t,y,x  Average Pentad Rate of Precipitation  [mm/day]
ENDVARS

-Karin

Thank you very much dear Karin for your help.

Cheers,

Kenedy