You can easily subset a NC file using NCO tools. Check this tutorial:

http://jisao.washington.edu/data/nco/

What software do you plan to use for analysis?

Samiksha,

which type of data did you download? Modelled Spectra? Gridded?

About modelled data you will find more information and tutorials there

https://forge.ifremer.fr/plugins/mediawiki/wiki/ww3/index.php/En:using_ww3:2013_fall_waves_school:waves_101

and about the altimeter wave data, it is fully described here:

ftp://ftp.ifremer.fr/ifremer/cersat/products/swath/altimeters/waves/

Cheers,

Fabrice

Hi,

to manage nc files, an easy matlab tool is availble: http://mexcdf.sourceforge.net/

Check nc_varget function to retrieve 2-D data from a generic (n-D) set

Alvise

Thanks all for the help.

I am planning to use ferret.

But, when I try to open this file in ferret, it shows all data in one axis (i). with different datasets. Even lat, long is defined as dataset. Due to which I cannot extract data for my interested region. If anyone can help me in assigning lat and long to two axis then I can extract the data for my required region.

I am using altimeter wave data (global track data).

Samiksha

Hi,

there are 2 useful tools to check and view how netcdf files are organized (ncview - unix/Linux, ncbrowse - Windows). I always use them before I extract data. To extract data and dimensions from a netcdf file in matlab, I can highly recommend this function: http://www.mathworks.com/matlabcentral/fileexchange/15177-netcdf-reader. It works for 32bit netcdf files and does not require additional libraries. Hope this helps a little.

Cheers, Christian

Dar Samiksha,

the altimeter data you are looking at are measurements ALONG THE SATELLITE TRACK: these are time series. Ferret is not designed to plot time series. So you should use something else (matab or octave for example as suggested by Andres).

We actually did some tutorials on this type of data (Andres prepared all this):

ftp://ftp.ifremer.fr/ifremer/cersat/products/gridded/wavewatch3/pub/COURS/WAVES_SHORT_COURSE/TUTORIAL_ALTI_VALID.tar.gz

The version with Octave should work.

Hi Samiksha,

I do have some Octave code (easy to adapt to Matlab) that can extract the alongtrack altimeter data for an area and store it in NetCDF format. Please let me know if it is of your interest.

Hello

Look at the Matlab routines for .nc files and netCDF folder, may be you will find one to solve your problem

Samiksha,

Does the IFREMER FTP has any synthetic aperture radar wave(SAR) mode data..? i have looked into the ftp but couldnt find helpful information