3.3. Parameterization, calibration and validation of the model Realistic parameters are obtained from current field study and also from the previous works by different authors [7-9] [26]. Due to unavailability of some parameter values in real field, secondary data
source is used to calibrate the parameters. They have been calibrated from the works of similar type of system throughout the world by different authors [27-34]. During calibration, each parameter is modified and best fit is selected after analyzing the results of each run. First year data set is used for calibration followed by validation using second year data set. Parameters along with their descriptions and values
which have been used for the standard run of the model are given in Table 2. The monthly average values of all the state variables of first year and second year are being used for calibration and validation of the model respectively. Calibration is done by adjusting selected parameters in the model to obtain a best fit between the model calculations and the field data collected during first year (March 2005 to February
2006). Validation of the model is performed using data collected during second year (March 2006 to February 2007). The model was run on STELLA 6.0 computer software (High Performance Systems Inc.) and simulated for the period of 365 days to observe the dynamic behaviour of all the state variables of detritus food web.