4.2 Results of the Validation
81
a)
b)
0
50
100
150
200
250
300
350
400
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Impact (km)
Simulation number
Threshold high
Limit high
Impact
Limit Low
Threshold low
Overall mean: 73 km
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Impact (km)
Simulation number
Threshold high
Limit high
Impact
Limit Low
Threshold low
Overall mean: 423 km
Fig. 4.14 Estimated impact calculated in ERA Acute v.1.1.0.27 for shoreline from the 20 oil drift
simulations performed for the EVOS case in OSCAR. a Flora, b Fauna
not very representative for the incidents, exemplified by the impact area in simulation
no. 6 and 15 for EVOS, with wind mainly from southwest during the modelled oil
spill and an impact area limited to the Valdez Bay area. In DHOS, much of the oil was
apparently trapped in a large stationary eddy on the northern part of the Loop Current
that would not necessary be present each year and therefore is not reproduced by the
oil drift simulations used as input to ERA Acute.
4.3 Discussion of the Validation
Estimating the extent of injury on natural resources has historically been a
contentious, uncertain, and politically charged process. The testing and validation of
the ERA Acute model is based on data that have a high degree of uncertainty. This
includes oil drift data, data on distribution and abundance of VECs, historical field
assessments of injury and the establishment of model parameters. A probabilistic
81
a)
b)
0
50
100
150
200
250
300
350
400
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Impact (km)
Simulation number
Threshold high
Limit high
Impact
Limit Low
Threshold low
Overall mean: 73 km
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Impact (km)
Simulation number
Threshold high
Limit high
Impact
Limit Low
Threshold low
Overall mean: 423 km
Fig. 4.14 Estimated impact calculated in ERA Acute v.1.1.0.27 for shoreline from the 20 oil drift
simulations performed for the EVOS case in OSCAR. a Flora, b Fauna
not very representative for the incidents, exemplified by the impact area in simulation
no. 6 and 15 for EVOS, with wind mainly from southwest during the modelled oil
spill and an impact area limited to the Valdez Bay area. In DHOS, much of the oil was
apparently trapped in a large stationary eddy on the northern part of the Loop Current
that would not necessary be present each year and therefore is not reproduced by the
oil drift simulations used as input to ERA Acute.
4.3 Discussion of the Validation
Estimating the extent of injury on natural resources has historically been a
contentious, uncertain, and politically charged process. The testing and validation of
the ERA Acute model is based on data that have a high degree of uncertainty. This
includes oil drift data, data on distribution and abundance of VECs, historical field
assessments of injury and the establishment of model parameters. A probabilistic