Study Of The Wind Speed Rainfall And Storm Surges For The Scheldt Estuary In Belgium

Abstract The Belgian coast and the Scheldt estuary are important for the Belgian economy. Coastal flood risks tend to increase due to climate change. This study was set out to investigate the wind speed surges and rainfall in the Scheldt estuary. The study explored the changes in mean and extreme winds according to the recent ENSEMBLES climate models and examined the dependency of extremes between surge with wind speed and surge with rainfall. The dependence analysis between surge and wind speed aimed to investigate whether climatic changes in wind speed can be transferred to changes in surge while the existence of dependence between surge and rainfall would require climate scenarios for rainfall upstream in the Scheldt basin to be correlated with climate scenarios for the downstream surge boundary. A special dependence measure 26967 developed by Buishand 1984 and Coles et al 2000 was followed. Data was extracted and processed using Matlab and CDO. The analysis of wind speeds showed that future wind speeds in the estuary based on the climate models will remain stable in comparison with the past wind speeds. Also wind direction will be mainly from 180-300 although slight shifts might appear towards more frequent south western winds. From the study of dependency there was no significant dependency between sea surge at Oostende coast and rainfall at different stations. The definition of significant dependency is strong or conservative. Above all the extremes events are more or less dependent. While the study has not found significant changes in wind speed and only slight changes in wind direction it is important to further investigate the impact of these changes on the Scheldt estuary using hydrodynamic models. The assessment of changes in extreme rainfall and sea surge need to be further studied.