Tuesday 16 Oct 2018: Moisture Transport by extra-tropical cyclones in the Southern Hemisphere
Victoria Sinclair - University of Helsinki
Harrison 170 11:00-12:00
Extra-tropical cyclones are known to be responsible for a large proportion of the poleward moisture transport in the mid-latitudes. However, not all cyclones are equal; some transport significantly more moisture polewards than others. The aim of the work presented in this seminar is to identify which cyclone characteristic (genesis latitude, maximum vorticity and poleward propagation speed), leads to the greatest variability in meridional moisture transport per cyclone. We use ERA-Interim reanalysis combined with an objective cyclone tracking algorithm (TRACK), a cyclone masking method and cyclone composites. Interestingly, the results show that cyclone intensity, quantified by maximum vorticity, has a weaker influence on how much moisture a cyclone can transport than other cyclone characteristics. This result suggests that studies considering how extra-tropical cyclones will change in the future should focus on cyclone track as well as cyclone intensity and number.