T Matthews, C Murphy, G McCarthy, C Broderick, R L Wilby

Environmental Research Letters

Published date January 18, 2018

Super Storm Desmond: a process-based assessment

  • States that 'Super' Storm Desmond broke meteorological and hydrological records during a record warm year in the British–Irish Isles (BI)
  • States that the severity of the storm may be a harbinger of expected changes to regional hydroclimate as global temperatures continue to rise
  • Adopts a process-based approach to investigate the potency of Desmond, and explores the extent to which climate change may have been a contributory factor
  • Determines—using an Eulerian assessment of water vapour flux—that Desmond was accompanied by an atmospheric river (AR) of severity unprecedented since at least 1979, on account of both high atmospheric humidity and high wind speeds
  • Lagrangian air-parcel tracking and moisture attribution techniques show that long-term warming of North Atlantic sea surface temperatures has significantly increased the chance of such high humidity in ARs in the vicinity of the BI
  • Concludes that, given exactly the same dynamical conditions associated with Desmond, the likelihood of such an intense AR has already increased by 25% due to long-term climate change
  • States that the analysis represents a first-order assessment, and further research is needed into the controls influencing AR dynamics