FAQ

Why does FLake not simulate the full depth of the lake?

• FLake assumes a rectangular shape of the basin and does not use the hypsograph file. The assumptions of FLake match best when using the mean depth of the lake. This is calculated from the hypsograph file inside export_location. So shallower depth of FLake is intended.
• Should you really wish to simulate the full depth of the lake, you can add “depth_w_lk: …” to the “FLake” section of the “model_parameters” section in the LER config file, with … the maximum depth of the lake.

Why am I getting the error “Error in get_meteo_time_step(… :Meteo file has irregular time steps!”?

• This error is thrown if the program registers irregular time steps in your meteo file. It would be good to check if this is indeed the case, but it can also be caused by not using the datetime format yyyy-mm-dd HH:MM:SS, in which case R reads the date in an incorrect manner.
• On many computers, Microsoft Excel is used as default when opening .csv files. Some versions of Excel automatically convert yyyy-mm-dd HH:MM:SS to dd/mm/yyyy HH:MM, which can cause this error. This can either be fixed a) in Excel by right-clicking the datetime cells, going to “Format Cells”, and then entering in the “Type” box: yyyy-mm-dd hh:mm:ss (this needs to be done every time opening the file in Excel and will be your local timezone) or b) by not using Excel and opening your input files in R or a text editor.
• Another common reason for this error is the absence of leap years. Some weather models give output always in 365 days a year without considering leap years, which will result in this error. So you would need to insert the missing leap days and fill in the missing forcing data on those dates (for example by interpolation).

What parameters can I enter in the model_parameters section of the LakeEnsemblR config file?

• You can specify any parameter that occurs in the model-specific configuration file of that model (check the model-specific directories). Functions inside LER will try to find the line where this parameter occurs and replace the value by the value you requested.
• You can either add one keyword, or two, split by “/” (e.g. “turb_params/k_min”). The first keyword is used to look for the section in which the parameter occurs, which can come in handy if the same parameter occurs in multiple sections.
• It is not yet possible to enter more than two keywords.
• A warning is thrown if the parameter cannot be found.

Can I enter a light-extinction coefficient (Kw) that varies over time?

• Yes, you can either add a value (i.e. constant over time) or a file name, in which you can vary Kw over time. Type LakeEnsemblR::get_template(“Light extinction”) to get the right format.

Can my outflow be different from my inflow?

• No, this functionality is not yet supported by LER. You can manually change the values of in- and outflow in the model-specific directories, but this might lead to unexpected differences between models.

How do I add additional members to my netcdf file?

• When you call run_ensemble, add the argument add = TRUE. This will add the run to the existing netcdf as a new member.