changes to run pyicon in picontrol period
in control period, there are many variables that do not exist in the era climatology file. Therefore the bias plots cannot be done. This MR put some conditions (bias plots only when var exists in refdata).
in control period, there are many variables that do not exist in the era climatology file. Therefore the bias plots cannot be done. This MR put some conditions (bias plots only when var exists in refdata).