May 25, 2016

Peak precipitation intensity in relation to atmospheric conditions and large-scale forcing at midlatitudes

Loriaux, Jessica M., Lenderink, Geert, Siebesma, A. Pier
Journal of Geophysical Research: Atmospheres
  • Presents a statistical analysis of the relation between large-scale conditions and hourly precipitation at midlatitudes, by using observations of the Netherlands combined with a regional reanalysis
  • Aims to gain a better understanding of the typical large-scale atmospheric conditions and large-scale forcing associated with extreme hourly precipitation and determine the typical differences between cases of extreme precipitation and weaker events
  • Performs an event-based analysis, to avoid double-counting, and considers the hourly peak intensity, rather than all hourly data
  • Finds that atmospheric large-scale profiles consistently show a clear separation between precipitation deciles, characterized by increasing instability and moisture content of the atmosphere for more extreme precipitation
  • Finds stronger events are characterized by larger atmospheric forcing preceding the event, which primarily relates to vertical motions
  • Analyzes—based on these results—four atmospheric parameters, describing atmospheric moisture, stability and large-scale convergence as potential indicators of strong precipitation events
  • Finds their correlations are weak despite positive relations between these parameters and the peak intensity