The Air‐Sea Response During Hurricane Irma's (2017) Rapid Intensification Over the Amazon‐Orinoco River Plume as Measured by Atmospheric and Oceanic Observations
Abstract
Hurricane Irma (2017) underwent rapid intensification (RI) while passing over the Amazon‐Orinoco River plume in the tropical Atlantic. The freshwater discharge from the plume creates a vertical salinity gradient that suppresses turbulent heat flux from the cool, ocean subsurface. The stability within the plume reduces sea surface temperature (SST) cooling and promotes energetic air‐sea fluxes. Hence, it is hypothesized that this ocean feature may have facilitated Irma's RI through favorable upper ocean conditions. This hypothesis is validated using a collection of atmospheric and oceanic observations to quantify how the ocean response influences surface flux and atmospheric boundary layer thermodynamics during Hurricane Irma's RI over the river plume. Novel aircraft‐deployed oceanic profiling floats highlight the detailed evolution of the ocean response during Irma's passage over the river plume. Analyses include quantifying the ocean response and identifying how it influenced atmospheric boundary layer temperature, moisture, and equivalent potential temperature (θE). An atmospheric boundary layer recovery analysis indicates that surface fluxes were sufficient to support the enhanced boundary layer θE (moist entropy) observed, which promotes inner‐core convection and facilitates TC intensification. The implicit influence of salinity stratification on Irma's intensity during RI is assessed using theoretical intensity frameworks. Overall, the findings suggest that the salinity stratification sustained SST during Irma's passage, which promoted energetic air‐sea fluxes that aided in boundary layer recovery and facilitated Irma's intensity during RI. Examination of the air‐sea coupling over this river plume, corresponding atmospheric boundary layer response, and feedback on TC intensity was previously absent in literature.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 17, 2020
- Source ID
- 10.1029/2019jd032368
Entities
People
- Elizabeth R. Sanabia
- Johna E. Rudzin
- Steven R. Jayne
- Sue Chen
Organizations
- National Academies of Sciences, Engineering, and Medicine
- National Oceanic and Atmospheric Administration
- National Research Council
- Office of Naval Research
- United States Naval Academy
- United States Naval Research Laboratory
- Woods Hole Oceanographic Institution