Opened 12 years ago

Closed 12 years ago

#206 closed help (fixed)

making netcdf files from irregular gridded data for reading with xconv

Reported by: anmcr Owned by: jeff
Component: UM Mesoscale Keywords: ancilliaries netcdf xconv
Cc: a.j.heaps@… Platform:
UM Version:

Description

Hello,

I want to create my own sea-ice ancillaries from daily SSMI data using the process of

1) use data to create a .nc file
2) read .nc file using xconv, interpolate to UM grid, save as .nc file
3) use .nc file and qrparm.mask.nc file to create ancillary using xancil

This technique was very effective at creating SST ancillary files based on regular gridded AVHRR data.

However, now I want to create seaice ancillaries using 'bootstrap' SSMI data which is on an irregular lat/lon grid, i.e. its lat, lon, and data are all 2d x-y arrays. I can read this data using IDL, but do not know how to, of if it is possible, to write the data as a netCDF file.

Is the only procedure to first interpolate the irregular data to a regular grid, using for example the IDL command, griddata?

Any suggestions would be very much appreciated.

Thanks,

Andrew (anmcr)

Change History (3)

comment:1 Changed 12 years ago by jeff

  • Cc a.j.heaps@… added
  • Owner changed from um_support to jeff
  • Status changed from new to assigned

Hi Andrew

If its irregular data then xconv won't be able to interpolate it, so you will need to interpolate the data to a regular grid first but if you are doing this you might as well interpolate onto the rotated pole LAM domain and not use xconv. We have a local IDL expert who can give you advice on writing netcdf files and interpolating to a rotated grid, but he is on holiday and not back until the 11 Dec. The idl netcdf routines are called NCDF_*.

Jeff.

comment:2 Changed 12 years ago by anmcr

Thanks Jeff for the reply.

I had a feeling that that was the case.

I guess from your message that the local IDL expert in Andy Heaps. I'II email hime once he's back if I still need some help.

Andrew

comment:3 Changed 12 years ago by jeff

  • Resolution set to fixed
  • Status changed from assigned to closed
Note: See TracTickets for help on using tickets.