North Atlantic winter wind storm variability across different time scales

[摘要] In this thesis atmospheric and oceanic conditions important for the development of wind storms on different time scales are analysed. The potential usefulness and limitations of seasonal prediction models and long-term reanalyses with respect to wind storm frequency is investigated and sources of potential seasonal predictability of wind storm frequency are discussed. On the synoptic scale tropospheric growth conditions such as baroclinicity, latent heat and upper level divergence show greater magnitudes of one standard deviation on average compared to all extra-tropical cyclones. Mid-latitude Rossby waves show generally greater amplitudes for different wave numbers during wind storm events. Greater amplitudes are also found in wave numbers not typically associated with storm track activity. The analysis of extra-tropical cyclones and wind storms on the seasonal scale reveal positive, significant skill for some European regions in state-of-the-art seasonal prediction models. North Atlantic sea surface temperatures (SST) are shown to be a source of seasonal predictability and a potential reason for the achieved skill for wind storm frequency predictions in reanalysis and AMIP-type sensitivity experiments. The role of tropical Pacific and Atlantic SST for the record number of wind storms over the UK in winter 2013/14 is discussed.

[发布机构] University:University of Birmingham;Department:School of Geography, Earth and Environmental Sciences

[关键词] G Geography. Anthropology. Recreation;GE Environmental Sciences