2.3.3. Baseline Data Processing with SWAT Weather Generator (SWAT-WGEN)

The weather data were statistically analyzed, and data qualities such as errors and outliers were assessed and adjusted by the weather database generator software (SWAT-WGEN). The data and their respective station coordinates (X, Y, and Z) were synchronized by the SWAT-WGEN. As a result, the SWAT model recognized the spatial distribution of the data supplied. SWAT-WGEN helps in statistical analyses, in data coding for SWAT use, and for data gap analyses as well as for spatial interpolation of the missed datasets. Special care was given to the input data within this study. The background data provided by the authorities were carefully checked and missing data were supplied if available. The data gaps in the collected baseline data were scattered, but on some days, they were sequential. These sequential data gaps ranged from one to only ten days maximum for some stations. The gaps were filled via interpolation by the software. These data gaps accounted for not

more than 65 days out of the total 27 years per station, which is less than 0.66% of the data items. Simple arithmetic means (taking the averages of the values of the data series available before and after the missed data dates) were also applied to those stations where the gaps were scattered and not sequential to restore the missing values.
