Andrew Saulter

Use of field measurements to improve probabilistic wave overtopping forecasts

The paper investigates the practicalities and potential value of coupling offshore to nearshorewave models, and nearshore-wave and surge models to coastline overtopping models and floodrisk indicators. The available coupled models include Ensemble surge models, offshore wave models, hydrodynamic wave transformation models and empirical wave overtopping formulae. The uncertainty associated with an individual model output, and the propagation of this incertainty forward through the modelling chain is handled through Monte Carlo simulation from either discrete or continuous probability distributions, based on the information available on each of the variables involved. The paper will concentrate on the collection and analysis of measured overtopping discharges at a site in North-west England. At the same site inshore wave measurements will be recorded for selected high tide events. The results from these field measurements will be used to calibrate and refine the Monte Carlo simulations.

Quantification of bias of wave measurements from lightvessels

ABSTRACT Wave measurements are presently made by the Met Office from moored buoys and lightvessels around the UK and are used for coastal flooding prediction, marine forecasting, wave climate studies and validation of wave forecast models. However, it has long been suspected that the wave measurements from the lightvessels are less accurate than those from the buoys. This paper presents the results of a study comparing both lightvessel and buoy wave measurements for the period 2011–2014 inclusive against output from the Met Office wave model to examine whether there is a systematic deficiency in the lightvessel wave measurements. The analysis showed that moored buoys generally agreed well with the model data, but lightvessels consistently reported lower wave heights and higher wave periods than the model.