CCSM or CAM manipulation

[nickh07@yahoo_com_au]

Hi,

I am part of a group simulating the Miocene epoch and currently
we are seeing substantial ice formation which we would like to eliminate
for the purpose of our experiment. I have been told there were no glaciers
in the input files for the runs and they currently only consist of the CAM,
CLM and the SOM components (Can sea ice form in a model which isn't
running CSIM? And is the land model responsible for glaciation?).

I was wandering if there is a way of stopping ice and snow formation, say a
switch which doesn't allow water to freeze no matter how cold it gets. Also, how many possible types of ice
formations are there in CCSM as it is not clear to me from reading the CAM
and CLM documentation. There is snow, sea ice, and glaciers only correct?
As I have also seen cloud ice and so forth.

cheers in advance

 

[rneale]

I am presuming you are performing experiments in the CCSM modelling framework as opposed to the CAM modelling framework? If so the integration consists of the 4 modelling components (atmosphere, land, ocean and ice). Options exist to specify that each of these components is either an active component or a data component. It seems that you may be using the active version of the sea-ice model (csm) such that ice is building up preumeably in response to cold temeratures (but maybe you want to be ice-free because of the Miocene generally being warmer?). You may be able to control this by selecting a data ice model in CCSM configuration scripts (dice6?). This basically saya that the ice is constant on a monthly basis and boundary files will be including which provides the relevant ice parameters. Obviously these data files will be for present day, but there is no reason why you cannot change the data in these files to be consistant with your required Miocene ice estimates and run the model with fixed ice.

I hope this helps, but if I have presumed too much about how you are running the model then provide extra details and I may be able to help further.

 

[nickh07@yahoo_com_au]

We are currently only running CAM coupled to CLM using the SOM. We have managed to turn off glaciers from the source code however snow and presumedly sea ice forms making polar temps cold.

Is the data ice model you mentioned a part of CAM or CLM? or is it part of the CSIM (which we are then not using). Effectively we would like to stop any ice formation in our model. If we can hold polar SST's at say > -1.8 then that would stop sea ice formation presumedly however we would still have to contend with snow.

thanks for the help,

Nick

 

[rneale]

OK, if you are using the SOM in the CAM framework did you calculate the required QFLUX fields using a run of CAM with Miocene forcing (SSTs and solar parameters)? If not, and you are using present day Qflux files then ice will form according to present day.

If ice is still forming with the correct Qflux forcing then you may want cut the wires that are creating ice in the csim4 model code that runs in cam. Unfortunately I think if you select the SOM then you have to use this ice model.