How to change geography and ice sheets?

[cmitas@rsmas_miami_edu]

Hello,

Which are the files that store the topography and the distribution of ice sheets?
May one modify these to, for example, run CCSM for an idealized continent configuration, and various ice sheet configurations?

Any guidance would be appreciated.

Cheers,
Chris

 

[jmccaa]

The distribution of ice sheets is a property of the land model, so you should probably either ask the land model liaison about that or post your question over in the CCSM part of the bulletin board, which land modelers might be more likely to see it.

The topography and land/ocean mask data for the standalone atmosphere resides in the initial conditions file (pointed to by the namelist variable NCDATA). You can change this as you see fit, but the model generally needs the topography to be filtered. There is a utility to handle these issues that is distributed with model in the directory models/atm/cam/tools/definesurf.

Jim

 

[jmccaa]

The following is incorrect:

There is a utility to handle [surface properties] that is distributed with model in the directory models/atm/cam/tools/definesurf

The code mentioned is not in the source distribution. It is, however, available via the CAM download page
http://www.ccsm.ucar.edu/php/ccsmAgreement.php?indexId=36

Please see the Utilities section at the bottom of the page. This code is distributed as is, with no user support.

Jim

 

[rnicholas@atmos_washington_edu]

The README file included in the definesurf package says...

The high resolution topography dataset used by definesurf is named topo.nc
and is included as part of the CAM distribution in the datasets tar
file. topo.nc was derived from the U.S. Navy Global Elevation 10-MIN dataset
DS754.0 Please refer to the following NCAR website for more information:

http://www.scd.ucar.edu/dss/catalogs/geo.html

...but the file topo.nc does not seem to exist within the CAM data distribution. And the informational URL is dead.

Any clue as to where topo.nc can now be found?

 

[hannay]

You can find the datasets for cam at on:
http://www.ccsm.ucar.edu/models/atm-cam/download/index.html


Near the bottom of the page, you will find

# topo10min.merged_c030506.nc (Updated: May/ 6/2003, Size: 27M)

A 10 minute averaged version of USGS gtopo30, with Caspian sea land mask merged from 10 minute Navy dataset (topo.nc).

 

[rnicholas@atmos_washington_edu]

Great -- thanks!

Perhaps someone could update the webpage and/or the definesurf package to indicate that this is the required dataset?

 

[rajkmsaini]

You can find the datasets for cam at on:
CAM 3.1 Download


Near the bottom of the page, you will find

# topo10min.merged_c030506.nc (Updated: May/ 6/2003, Size: 27M)

A 10 minute averaged version of USGS gtopo30, with Caspian sea land mask merged from 10 minute Navy dataset (topo.nc).

Hello Hannay,

I need to perform a simulation by flattening the maritime continent (i.e., 0.0 height of topography) with monthly mean climatological SST.

Can you tell me how I will prepare topo.....nc file?

Please suggest steps for that.

Thanks in advance.