Re: [ferret_users] How to make a monthly composite?

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi,
A descriptor file would let you link all of these together into a virtual dataset, then you could read it and do any computations you want with the year-long time axis.

The tool make_des to create descriptor files:
http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/converting-to-netcdf/CREATING-A-MULTI-FILE-NETCDF-DATA-SET#_VPINDEXENTRY_1143

works with url's, but the way the datasets are named on the server, I don't think there's a way to specify the whole set of files. Make a file from the first two

make_des http://data.nodc.noaa.gov/thredds/dodsC/pathfinder/Version5.2/2010/20100101003725-NODC-L3C_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.2_NOAA18_G_2010001_night-v02.0-fv01.0.nc http://data.nodc.noaa.gov/thredds/dodsC/pathfinder/Version5.2/2010/20100102002639-NODC-L3C_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.2_NOAA18_G_2010002_night-v02.0-fv01.0.nc > night.des

You could add to the descriptor file yourself, listing each dataset name with its timestep. It looks like the times in the files aren't equally spaced, so you need to get the timesteps out of the remaining datasets. Either with Ferret

yes? use "http//data.nodc..."
yes? list/prec=10 t[gt=SEA_SURFACE_TEMPERATURE]

or with an ncdump command such as

> ncdump -v time http://data.nodc...

-Ansley

On 3/20/2014 1:16 PM, Luke M wrote:

Hi everyone

I would like to create nighttime SST monthly composites for the year 2010 using the data from the NOAA Pathfinder v5.2 (http://data.nodc.noaa.gov/thredds/catalog/pathfinder/Version5.2/2010/catalog.html), but I'm a bit unclear on how to do this. Does anyone have any examples that could help me achieve this?

Thanks,

      L.