Dr. Nicolas Bruneau (NOC)
Ocean- and waves-induced feedbacks on tropical cyclone development
Tropical cyclones (TCs) are one of the most damaging natural catastrophes. Due to intense destructive winds and heavy rainfall associated with storm surges, large waves and flooding, TCs are a major threat to human lives and properties. Therefore, accurately forecasting their structure and track is crucial to be able to provide useful warnings, to improve global resilience and to preserve public confidence in forecasts. Although significant progress has been achieved over the past four decades, particularly reducing track errors, cyclone intensity forecasts have seen no large improvements and seasonal uncertainty of the performance still occurs in four- to five-day forecasts.
Air-sea heat and moisture exchanges are two key processes in TC intensification and are directly linked to ocean surface cooling / warming due to changes of mixed layer depth and upwelling / downwelling. Therefore, ocean models need to accurately predict the rate and pattern of sea surface temperature (SST) cooling and the upper-ocean characteristics more generally. Here, we investigate through a set of idealised experiments two different physical processes between the ocean and the atmosphere :
1 - The impact of wave-current interactions in mixing a stratified coastal ocean, before landfall using ocean-wave coupled experiments as well as the feedbacks to a TC with atmosphere-ocean-wave fully-coupled simulations.
2 - The impact of warm- or cold-core ocean eddies on the cyclone structure and intensity.