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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Uncertainty due to choice of measurement scale in extreme value modelling of North Sea storm severity
AU - Reeve, D.T.
AU - Randell, D.
AU - Ewans, K.C.
AU - Jonathan, P.
PY - 2012
Y1 - 2012
N2 - Modelling extreme storm severity is critical to design and reliable operation of marine structures. Extreme hindcast storm peak significant wave heights (HS) for 816 locations throughout the North Sea are modelled, using the four parameter Poisson point process model of Wadsworth et al. (2010), incorporating measurement scale variability via a BoxCox transformation. The model allows estimation of the posterior distribution for measurement scale parameter and point process parameters within a Bayesian framework. The effect of measurement scale on return values of significant wave height (HS) is quantified by comparison with a three parameter Poisson point process model ignoring measurement scale uncertainty. It is found that the median value (over all locations) of the median posterior BoxCox parameter (per location) is approximately 0.7, suggesting that the appropriate measurement scale for extreme value analysis is HS0.7. The value of the median BoxCox parameter (per location) varies considerably between locations, with a 90% uncertainty band of approximately (0.2, 2.2) and quartiles of 0.4 and 1.2; the value of BoxCox parameter is also influenced by threshold choice for extreme value analysis in particular. The ratio (over all locations) of the (posterior median) return value from the four parameter model to the return value from the three parameter model (and a return period of 100 times the period of the hindcast) has a median value of 0.92, suggesting that median return values may be reduced for this data set by better modelling of measurement scale effects. The ratio of return values has a 90% uncertainty band of approximately (0.72, 1.37), illustrating the extra variability in return values that incorporation of measurement scale uncertainty introduces. © 2012 Elsevier Ltd. All rights reserved.
AB - Modelling extreme storm severity is critical to design and reliable operation of marine structures. Extreme hindcast storm peak significant wave heights (HS) for 816 locations throughout the North Sea are modelled, using the four parameter Poisson point process model of Wadsworth et al. (2010), incorporating measurement scale variability via a BoxCox transformation. The model allows estimation of the posterior distribution for measurement scale parameter and point process parameters within a Bayesian framework. The effect of measurement scale on return values of significant wave height (HS) is quantified by comparison with a three parameter Poisson point process model ignoring measurement scale uncertainty. It is found that the median value (over all locations) of the median posterior BoxCox parameter (per location) is approximately 0.7, suggesting that the appropriate measurement scale for extreme value analysis is HS0.7. The value of the median BoxCox parameter (per location) varies considerably between locations, with a 90% uncertainty band of approximately (0.2, 2.2) and quartiles of 0.4 and 1.2; the value of BoxCox parameter is also influenced by threshold choice for extreme value analysis in particular. The ratio (over all locations) of the (posterior median) return value from the four parameter model to the return value from the three parameter model (and a return period of 100 times the period of the hindcast) has a median value of 0.92, suggesting that median return values may be reduced for this data set by better modelling of measurement scale effects. The ratio of return values has a 90% uncertainty band of approximately (0.72, 1.37), illustrating the extra variability in return values that incorporation of measurement scale uncertainty introduces. © 2012 Elsevier Ltd. All rights reserved.
KW - Extreme value analysis
KW - Measurement scale
KW - Offshore design conditions
KW - Bayesian frameworks
KW - Box Cox transformation
KW - Data sets
KW - Effect of measurements
KW - Extreme value
KW - Four-parameter model
KW - Hindcasts
KW - Median value
KW - North Sea
KW - Offshore design
KW - Point process
KW - Poisson point process
KW - Posterior distributions
KW - Reliable operation
KW - Return periods
KW - Return value
KW - Significant wave height
KW - Three parameters
KW - Three-parameter models
KW - Threshold choice
KW - Measurements
KW - Offshore structures
KW - Storms
KW - Value engineering
KW - Water waves
KW - Uncertainty analysis
KW - Bayesian analysis
KW - hindcasting
KW - modeling
KW - severe weather
KW - significant wave height
KW - storm
KW - uncertainty analysis
KW - Atlantic Ocean
U2 - 10.1016/j.oceaneng.2012.07.001
DO - 10.1016/j.oceaneng.2012.07.001
M3 - Journal article
VL - 53
SP - 164
EP - 176
JO - Ocean Engineering
JF - Ocean Engineering
SN - 0029-8018
ER -