Relative humidity is an optional forcing data. It can be used for calculation of potential evaporation. Several of the available model options for potential evaporation depend on vapor pressures and net radiation, which may be calculated with the help of relative humidity data.

The file is located in the forcingdir folder. Relative humidity (unitless value 0-1) is given for all time steps. The RHobs-file is read only if readhumid is set in info.txt.

The file may have comment rows in the beginning of the file. These rows have to begin with !!. The first row read is column headings. It holds a text string (e.g. 'date', no spaces allowed) for the first column, and integers in the form of station or subbasin ID numbers for the rest of the columns.

The first column is date-time. The default format is yyyy-mm-dd [HH:MM], where hour and minutes are necessary if the timestep is shorter than one day. The date-time is the beginning of the timestep. It is possible to use another date-time format: yyyymmdd[HHMM]. It is expected for all forcing files, if readformat 1 is set in info.txt.

The second to last columns are relative humidity for all stations or subbasins. The ID number (first row) may be rhobsid or subid. If rhobsid is used, several subbasins may use the same relative humidity time series. subid is defined in GeoData.txt. The order of subbasins in RHobs.txt does not have to be same as in GeoData.txt. rhobsid may be defined in ForcKey.txt.

Example snippet of RHobs.txt file:

date         1234  1245 
1990-01-01   0.7     0.75  
1990-01-02   0.8     0.65 
... 

RHobs_nnn.txt holds relative humidity forcing data for sequence with seqnr nnn. For seqnr 0 RHobs.txt is used.