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Intense sub-kilometer-scale boundary layer rolls observed in hurricane fran
1School of Meteorology, University of Oklahoma, 100 East Boyd Street, Norman, OK 73019, USA.
Science (New York, N.Y.)
|May 6, 1998
Summary
Intense, small-scale boundary layer rolls were observed during hurricane Fran using high-resolution radar. These structures explain hurricane gustiness and varying damage patterns, unlike lower-resolution radar data.
Area of Science:
- Meteorology
- Atmospheric Science
- Hurricane Research
Background:
- Landfalling hurricanes cause significant damage and gustiness.
- Surface damage patterns after hurricanes are often geographically variable.
- The role of small-scale atmospheric structures in hurricane impacts is not fully understood.
Purpose of the Study:
- To investigate the existence and impact of sub-kilometer-scale boundary layer rolls during hurricane landfall.
- To determine if these structures contribute to observed hurricane damage patterns and gustiness.
- To compare high-resolution radar data with operational radar data for low-level wind speed estimation.
Main Methods:
- Utilized the Doppler On Wheels (DOW) mobile weather radar for high-resolution observations.
- Conducted observations near the landfall point of Hurricane Fran (1996).
- Contrasted DOW data with lower-resolution data from an operational weather radar.
Main Results:
- Revealed intense, sub-kilometer-scale boundary layer rolls near the hurricane landfall.
- Demonstrated that these rolls strongly modulated near-surface wind speed.
- Operational radar underestimated peak low-level wind speeds compared to DOW.
Conclusions:
- Boundary layer rolls are a likely cause of geographically varying hurricane surface damage.
- These structures contribute significantly to hurricane gustiness by transporting high-velocity air downward.
- High-resolution radar is crucial for accurately assessing low-level wind speeds in hurricanes.