Role of Moisture on tropical cyclone development

What is the role of moisture on tropical cyclone development?
  •  Methodology: Utilized Dr. Brian Tang's Axisymmetric Simplified Pseudoadiabatic Entropy Conserving Hurricane (ASPECH) Model to simulate tropical cyclone development under varying moisture conditions.
  • Summary: The driest experiment had descending motion and dry air entrainment closer to the inner core compared to the moistest experiment, resulting in a reduced area of upward motions and an increased spinup timescale.
Time-averaged (24 hours before intensification) cross sections of the percentage of updrafts exceeding 0.05 m/s (shaded) and the mass streamfunction (contoured every 4x10^8 kg/s) of the driest and moistest initial moist entropy profiles.

African Easterly Waves and Tropical Cyclogenesis

Do African Easterly Waves (AEWs) that develop north of the African Easterly Jet (AEJ) contribute to tropical cyclogenesis? 

Dynamically, how do these waves cross to the south from the dry Sahara to the moisture-rich rainy region?
  • Methodology: Utilized the ECMWF ERA-Interim Reanalysis to track vortices north of the AEJ.
  • Methodology: Completed a vorticity budget to determine the crossing mechanism of the Northern Waves.
  • Summary: Northeasterly flow transported the shallow Northern Waves under the AEJ to the south. After crossing, these waves had the potential to undergo tropical cyclogenesis. 
Streamlines at 850 hPa (contours) and zonal wind at 600 hPa  (shaded) to represent the AEJ. Topography is shaded in green. The blue line displays the track of the AEW. This AEW ultimately became Hurricane Katrina (2005). 

Warm core development and tropical cyclone intensity change 

How does a varying height and/or depth of a warm core change a tropical cyclone's intensity?
  • Methodology: Theorized how the minimum sea level pressure (MSLP) of a tropical cyclone would change under varying heights, depths, and strengths of the warm core. 
  • Methodology: Used the Hurricane Weather Research and Forecasting (HWRF) model to examine the warm core of Hurricane Earl (2010) during its rapid intensification. 
  • Summary: Typically, forecasters look at the height of the warm core to estimate intensity. These results suggest that the depth of the warm core is also important.
Idealized parabolic warm cores with a vertical depth from 6000 m to 16000 m, (b) Vertical depth from 6000 m to 14000 m, (c) Vertical depth from 6000 m to 12000 m, and (d) Vertical depth from 10000 m to 16000 m. The resulting MSLP for each parabola is shown.