Assessment of the Effects of Air-Sea-Land Interaction Processes on the Intensity and Impact of Modelled and Observed Coastal Extratropical Cyclones

摘要

This investigation compares observed values with global circulation model (GCM) predictions of those atmospheric forcing variables relevant to coastal flooding prediction. Both reanalysis and predictive GCMs models are investigated. While the limitations of these models in representing tropical storms are well established, in this investigation we have completed an assessment of their performance in more temperate regions as a function of latitude along the eastern United States and Australian coasts. The models represent the probabilities and extreme values of atmospheric pressure very well. Their performance in relation to wind and rainfall is less impressive but the modelled values are of similar magnitude to those observed. The models do simulate large-scale extreme events with mean surface pressures, winds and rainfalls that are of similar magnitude to those observed. Consequently, when combined with appropriate downscaling techniques, these models yield a direct method of defining the joint probability of the combinations of extreme low surface pressures, winds and rainfall in a way that has not previously been possible. GCM data provide a unique new means of determining the joint probability of those atmospheric variables primarily responsible for coastal inundation and storm damage in highly-populated temperate regions.