Coastal Protection and Risk
Return level and confidence interval (CI) for storm surge and higher wave heights have a tendency to be misunderstood. People may believe the range of CI to be indicated as that the maximum value will take during the future return period with a certain probability. Prediction Interval (PI) should be distinguished with CI. Numerical examples are demonstrated with a historical record of a bay in Japan. In that practice, we examine also the dilemma of bias and variance by using the threshold to censor the troublesome lower values even in the annual maximum value of sea deviance.