Authors

Daniel Masia

Document Type

Internship Report

Publication Date

Spring 2019

Abstract

The purpose of this project was to use observational and forecast model data from Hurricane Irma (2017) to investigate its reflectivity structure during its second episode of rapid intensification (RI), which took place from 0900 UTC 3 September to 2000 UTC 5 September. The radar reflectivity and precipitation structure during Irma’s second episode of rapid intensification are described in detail, investigating possible processes that help us to clarify the radial, azimuthal, and temporal distribution of deep convection, and its relationship with intensity change. All the data used for this study was obtained from the Hurricane Research Division (HRD) / Atlantic Oceanographic and Meteorological Laboratory (AOML) of the National Ocean and Atmospheric Administration (NOAA). Observational data collected in hurricane Irma by the Stepped Frequency Microwave Radiometer (SFMR), the lower fuselage (LF) radar and the tail Doppler radar on the NOAA WP-3D aircraft were analyzed. Reflectivity fields demonstrated that the degree of symmetry is greater with increasing TC intensity. A detailed analysis of the mean rain rate (RR) areas related to every dBZ range showed that during RI most of the mean RR regions are greater in areal extent than the mean RR areas corresponding to the same dBZ ranges prior to RI. Calculations based on LF radar images revealed that net latent heat release (LHR) within 111 km of the circulation center increases by 34% during RI. Overall, the results of this project may be helpful in guiding toward a better understanding of rapid intensification, the mechanisms that drive it, and those which sustain it.

Comments

Department: ATM

MPS Track: WFC

Location: Hurricane Research Division / Atlantic Oceanographic and Meteorological Laboratory in National Oceanic and Atmospheric Administration

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