CAM Tutorial -- Example 2 -- Increase orographic height

[rddixon@wisc_edu]

Thanks so much for putting all the tutorials from this summers session on the web including the videos of the presentations which went with each.

The other night I was screwing around with changing topography following the steps in the CAM tutorial and found that I couldn't access the specified topography file in the directory:

$DIN_LOC_ROOT = /fis/cgd/csm/cseg/inputdata

I found that the input data for my run was actually found in

$DIN_LOC_ROOT = /fs/cgd/csm/inputdata

More importantly, when I was talking with a colleague about altering topography in models he pointed out that there might be serious errors in mass balance if the initial pressure at the surface is not renormalized. In my case I was decreasing topography heights. Will this create a vacuum in effect that will send shock waves across the planet when I run the model with the altered terrain? I haven't done it yet and will post back when I do, but I was just curious as to what other's thoughts on this problem are. Thanks!

 

[andrew]

There may be initial waves generated from reductions in topography, but these should rapidly go away. It is usually good policy to allow any model run to spin up for 3-12 months before looking at any output.

You might want to alter initial surface pressure in the initial condition file when topography is removed or changed to better reflect the new surface height. That is one solution. My guess is that if you just let the model spin up for several months (like 12) before looking at the output, it will be fine.

 

[maythywinter@australia_edu]

Thank you for your sharing !