5.7 Meteorological forcing

Within this tab (Figure 31) you need to specify which meteorological forcing variables you want to create for the SPHY model:

• Precipitation

• Temperature (average, maximum, and minimum)

If you already have created your own forcing data manually, then you can skip this section. Otherwise start by selecting the variables that you need to process (precipitation and/or temperature). After this step you need to tell the GUI where to find the data for your forcing variable. This can either be database based, or based on user-defined station data. For more information regarding the source of the database forcing data we refer to the Appendices. Temperature data is calculated using a lapse rate of -0.0065 °C/meter elevation increase. Both precipitation and temperature data are interpolated using bilinear[1] interpolation

The example of Figure 32 shows that both precipitation and temperature forcing will be created using the GUI, whereas precipitation data will be based on the database, and temperature data will be based on user-defined station data. If you select to use station data, then you need to select a station location csv-file, and a station data csv-file. It is important that the number of stations in the location file match the number of stations in the data file. The required csv file format is shown in Figure 33 through Figure 35. Make sure that the selected forcing period to process (Section 3.2.3) is covered by the database and/or user-defined station data. Finally click the Create forcing button to start creating the forcing data.

This may take a while depending on the length of the period to process, and the extent and spatial resolution of your selected area. During processing the GUI may look something similar like Figure 36. After this step has been completed you are done with processing all SPHY model input data.

Figure 31: Overview of the Meteorological forcing tab.

Figure 32: Setting the options in the Meteorological forcing tab, using precipitation data from the database and temperature data from user-defined stations.

Figure 33: Format of location csv-file, containing 5 stations. Elevation units are in MASL. Coordinates need to be provided in latitude (lat) and longitude (lon). Names can be dummy values.

Figure 34: Format of precipitation data csv-file, containing data for 5 stations. Precipitation units are in mm.

Figure 35: Format of temperature data csv-file, containing data for 5 stations. The order is from left to right: average, maximum, minimum temperature. Units of temperature are degrees Celsius.

Figure 36: Processing of meteorological forcing data.

[1] https://en.wikipedia.org/wiki/Bilinear_interpolation