Dr. Collimore presented a seminar titled “The Impact of High Aerosol Concentrations on Tropical Cyclone Formation”.
ABSTRACT:
Prior studies have shown that high levels of aerosols in the environment of convective clouds can cause the convection to become more vigorous through a five step process. Tropical cyclones (TCs) start as clusters of convective clouds and vigorous convection is important for the development of a cluster into a TC. This study tests the hypothesis that high aerosol content in the vicinity of a tropical convective cloud cluster increases the chance that the cluster will develop into a TC by invigorating its convection. To test this hypothesis, this study centers on 63 clusters that developed into TCs (developers) and 98 clusters that dissipated before becoming a TC (nondevelopers). Using aerosol observations from the MODIS satellite instrument, it was established that the average aerosol content surrounding developers was significantly higher than that surrounding nondevelopers. Furthermore, other satellite measurements (from MODIS and AIRS) provide evidence that each of the five steps associated with convective invigoration by aerosols took place in the developers, suggesting that the large aerosol content surrounding developers invigorated their convection. Altogether, the data suggest convective cloud clusters embedded in regions with elevated aerosol levels have a greater likelihood of developing into TCs because the aerosols invigorate their convection.
A recording of the presentation (blank screen for the first 56 s) is available on the anonymous ftp site: ftp://ftp.aoml.noaa.gov/hrd/pub/blog/seminars/2019/Collimore_HRD_Seminar_20190305.mp4
