Publication Date

2012-07-27

Availability

Open access

Embargo Period

2012-07-27

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Meteorology and Physical Oceanography (Marine)

Date of Defense

2012-05-08

First Committee Member

Bruce Albrecht

Second Committee Member

Frank Marks Jr.

Third Committee Member

Paquita Zuidema

Fourth Committee Member

Kevin Kloesel

Fifth Committee Member

Okhee Lee

Abstract

This dissertation investigates the wind structure observed in outer rainbands of three tropical cyclones in August and September 2008 in South Florida. Average wind profiles during fourteen stratiform periods are evaluated using a velocity-azimuth display (VAD) technique applied to Level-2 Miami (KAMX) WSR-88D data to study wind structure in high vertical resolution from a height of 65 meters to 6550 meters above ground level. The maximum horizontal wind speed in the rainbands is typically observed between 1000-1500 meters in height, with occasional evidence of a secondary horizontal wind maximum near 3500-5000 meters. This secondary maximum is found to be stronger than the low-level maximum in four cases of stronger storms observed at further distances (425-450 km) from storm center. Storm-relative wind components are calculated, and radial wind profiles show a mean switch from radial inflow at low levels to radial outflow around 2500-3000 meters AGL. The radial inflow maximum is around 500 meters, while maximum outflow is much more variable. Temporal variability within one four hour period is examined, and an ascending and strengthening low-level wind maximum is seen, along with a decrease in the low-level radial inflow over time.

Keywords

hurricane; stratiform rainband; radar; science education

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