Pesticides Research, 64 – Technical Documentation of PestSurf, a Model describing Fate and Transport of Pesticides in Surface Water for Danish Conditions

Technical Documentation of PestSurf, a Model describing Fate and Transport of Pesticides in Surface Water for Danish Conditions

5 Statistical Functions Included

Statistical functions have not been implemented in the user interface, since the execution of one run last for about two days. Considering that the intelligent Monte Carlo simulation would demand about 25 runs a statistical evaluation of the model output was considered as unrealistic for practical purposes. However, a spread sheet deriving 25 sets of input parameters on the basis of the properties of the active substances and the framework for intelligent Monte Carlo analysis provided by (Styczen et al 2003) have been prepared. The spreadsheet consist of two input pages and an output page. The first input page is similar to the input page of the user interface. At the second input page the uncertainty of selected input parameters must be tabulated in terms of a standard deviation for the log transformed data. Hence it is assumed that the input parameters follows a log normal distribution. When the input pages have been filled out a suggestions for 25 data sets appear from the output menu. The data sets can then be entered to the user interface of the model and the output of these 25 model runs can be used for statistical evaluations.