5.3 Uncertainty Scoring of the Parameters
95
Table 5.1 (continued)
Main parameter A: Strength of knowledge (function where it is used)
B: Belief that the value may deviate from the average assumption (natural
variation of parameter)
C: Sensitivity of function to parameter (sensitivity index)
Th
A Moderate/weak Due to lack of experimental data, it is difficult to assign
specific threshold levels for lethal oil film thickness
B Moderate
C High
Comments/recommendations:
A threshold value, lower value is conservative. Oil thickness is calculated by
the oil drift model. Use Best Practice for ODS to ensure comparable and
reliable predictions. Based on present knowledge, reducing Th from 10 to
2 µm, increases the impact with a factor of approximately 2.0–2.5, depending
on the distribution of the VEC and the distance to the release point
N per cell
A Moderate/weak
Depends on the quality of the data received from the data provider. The
quality of the data for the NCS is considered high
B High
C Moderate/high
Comments/recommendations:
Use the best available data to reduce uncertainty. Use the same data for
comparable studies. The definition of a “population” is important
5.3.2 Water Column Compartment
Results of the scoring and evaluation of water column parameters are given in
Table 5.3 for the impact parameters and Table 5.4 for recovery parameters.
5.3.3 Shoreline Compartment
Results of the scoring and evaluation of shoreline parameters are given in Table 5.5
for impact parameters and Table 5.6 for recovery parameters.
5.3.4 Seafloor Compartment
Results of the scoring and evaluation of seafloor parameters are given in Table 5.7
for impact parameters and Table 5.8 for recovery parameters.
95
Table 5.1 (continued)
Main parameter A: Strength of knowledge (function where it is used)
B: Belief that the value may deviate from the average assumption (natural
variation of parameter)
C: Sensitivity of function to parameter (sensitivity index)
Th
A Moderate/weak Due to lack of experimental data, it is difficult to assign
specific threshold levels for lethal oil film thickness
B Moderate
C High
Comments/recommendations:
A threshold value, lower value is conservative. Oil thickness is calculated by
the oil drift model. Use Best Practice for ODS to ensure comparable and
reliable predictions. Based on present knowledge, reducing Th from 10 to
2 µm, increases the impact with a factor of approximately 2.0–2.5, depending
on the distribution of the VEC and the distance to the release point
N per cell
A Moderate/weak
Depends on the quality of the data received from the data provider. The
quality of the data for the NCS is considered high
B High
C Moderate/high
Comments/recommendations:
Use the best available data to reduce uncertainty. Use the same data for
comparable studies. The definition of a “population” is important
5.3.2 Water Column Compartment
Results of the scoring and evaluation of water column parameters are given in
Table 5.3 for the impact parameters and Table 5.4 for recovery parameters.
5.3.3 Shoreline Compartment
Results of the scoring and evaluation of shoreline parameters are given in Table 5.5
for impact parameters and Table 5.6 for recovery parameters.
5.3.4 Seafloor Compartment
Results of the scoring and evaluation of seafloor parameters are given in Table 5.7
for impact parameters and Table 5.8 for recovery parameters.