A new INTEXseas paper on extreme wet seasons

In a study led by Emmanouil Flaounas we identified and studied the occurrence and synoptic dynamics of extreme wet seasons unsing ERA-Interim and an extensive collection of weather feature identification climatologies. In this study we employed a temporally flexible definition of “wet seasons” and their extremes by identifying at each grid point the 90-day periods with the most accumulated precipitation. Connecting these extreme wet seasons to spatial objects (see figure below) then allows to study the dynamical drivers of these individual events. These analyses reveal a wide palette of synoptic storylines for extreme wet seasons that strongly vary in space. For example, an extreme wet season over the tropical Atlantic resulted from a single particularly strong tropical cyclone, while over Iberia and the US West Coast extreme wet seasons occurred due to anomalousely frequent tropical moisture exports and extratropical cyclones and an extreme wet season over Northern Australia resulted form a complex interplay between extratropical Rossby wave breaking, a landfalling tropical cyclone and anomalousely frequent surface cyclones. This paper is the first to comprehensively chracterize extreme wet seasons around to globe with regard to their weather feature characteirstics and is now in the discussion phase in Weather and Climate Dynamics.

The Figure above shows the 100 largest extreme wet season objects in the ERA-Interim period 1979-2018.