Diagnosing radial ventilation in dropsonde observations of Hurricane Sam (2021)

We used this method to investigate ventilation changes over three consecutive sampling periods in Hurricane Sam (2021), which underwent substantial intensity changes over 3 days. During the first and last periods, coinciding with intensification, the ventilation was relatively small due to a lack of spatial correlation between radial flow and 9e e azimuthal asymmetries.

During the second period, coinciding with weakening, the ventilation was relatively large. The increased ventilation was caused by greater shear associated with an upper-level trough, tilting the vortex, along with dry, low-9e 9 e air wrapping in upshear. The spatial correlation of the radial inflow flow and anomalously low-9e 9 e air resulted in large ventilation at mid- to upper levels.