My own atm. forcing file: replacing missing FLDS

[hannah0304]

Hello,

I am running a single-point simulation with my own atmospheric forcing files.
Due to the lack of data availability, I have missing values in FLDS, which is causing the problem..
Replacing missing values with 0 does not make sense because I believe the run is not possible with 0 or negative FLDS values.
I wonder if there is any suggestion for replacing missing FLDS values.

 

[slevis]

Suggestions for @hannah0304 are welcome from everyone in the community.

 

[oleson]

If FLDS is missing, the datm should supply incoming longwave according to a formulation by Idso (1981) as described here:

2.32. Land-Only Mode — ctsm CTSM master documentation

You would just need to tell the datm not to expect FLDS from your forcing files.

For example, for GSWP3V1 forcing there should be a file in your CaseDocs directory:

datm.streams.txt.CLMGSWP3v1.TPQW

If you copy that into your case directory and prepend "user_" to the file, e.g.,

cp CaseDocs/datm.streams.txt.CLMGSWP3v1.TPQW user_datm.streams.txt.CLMGSWP3v1.TPQW

and then remove the line:

FLDS lwdn

the longwave calculation should be invoked.

Of course, you could always derive downward longwave from other formulations in the literature and add it to your forcing files.

 

[wwieder]

To second Keith here, I often run single point cases without FLDS inputs to DATM to avoid this gap issue. If you're interested, then you can compare the model calculated incoming longwave with the observations (when they exist). It's a good sanity check to make sure the model is behaving correctly.

 

[hannah0304]

Thank you all for your suggestions!
@oleson I was able to solve the problem with your comments
@wwieder I strongly agree :) I should check over the periods where I have observation data