scholarly journals Fetch-limited surface wave growth inside tropical cyclones and hurricane wind speed retrieval

2016 ◽  
Author(s):  
Paul A. Hwang ◽  
Xiaofeng Li ◽  
Biao Zhang ◽  
Edward J. Walsh
Keyword(s):  
Surface Wave ◽  
Wind Speed ◽  
Tropical Cyclones ◽  
Wave Growth ◽  
Hurricane Wind ◽  
Limited Surface

scholarly journals Azimuthal and Radial Variation of Wind-Generated Surface Waves inside Tropical Cyclones

2016 ◽  
Vol 46 (9) ◽  
pp. 2605-2621 ◽  
Author(s):  
Paul A. Hwang ◽  
Edward J. Walsh
Keyword(s):  
Wind Speed ◽  
Half Plane ◽  
Wind Wave ◽  
Coverage Area ◽  
Wave Growth ◽  
Local Maxima ◽  
Growth Functions ◽  
Hurricane Wind ◽  
Energy And Momentum ◽  
The Right

AbstractFor wind-generated waves, the wind-wave triplets (reference wind speed, significant wave height, and spectral peak wave period) are intimately connected through the fetch- or duration-limited wave growth functions. The full set of the triplets can be obtained knowing only one of the three, together with the input of fetch (duration) information using the pair of fetch-limited (duration limited) wave growth functions. The air–sea energy and momentum exchanges are functions of the wind-wave triplets, and they can be quantified with the wind-wave growth functions. Previous studies have shown that the wave development inside hurricanes follows essentially the same growth functions established for steady wind forcing conditions. This paper presents the analysis of wind-wave triplets collected inside Hurricane Bonnie 1998 at category 2 stage along 10 transects radiating from the hurricane center. A fetch model is formulated for any location inside the hurricane. Applying the fetch model to the 2D hurricane wind field, the detailed spatial distribution of the wave field and the associated energy and momentum exchanges inside the hurricane are investigated. For the case studied, the energy and momentum exchanges display two local maxima resulting from different weightings of wave age and wind speed. Referenced to the hurricane heading, the exchanges on the right half plane of the hurricane are much stronger than those on the left half plane. Integrated over the hurricane coverage area, the right-to-left ratio is about 3:1 for both energy and momentum exchanges. Computed exchange rates with and without considering wave properties differ significantly.

scholarly journals Tropical cyclone simulations over Bangladesh at convection permitting 4.4 km & 1.5 km resolution

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Sea Level ◽  
Tropical Cyclones ◽  
Weather Forecasting ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Level Pressure ◽  
Medium Range ◽  
Gust Speed

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.

scholarly journals Topographic Speed-Up Effects and Observed Roof Damage on Bermuda following Hurricane Fabian (2003)

2013 ◽  
Vol 28 (1) ◽  
pp. 159-174 ◽  
Author(s):  
Craig Miller ◽  
Michael Gibbons ◽  
Kyle Beatty ◽  
Auguste Boissonnade
Keyword(s):  
Surface Roughness ◽  
Wind Speed ◽  
Surface Wind ◽  
Open Water ◽  
Clear Trend ◽  
Wind Speeds ◽  
Research Division ◽  
Hurricane Wind ◽  
Layer Flow ◽  
Observed Damage

Abstract In this study the impacts of the topography of Bermuda on the damage patterns observed following the passage of Hurricane Fabian over the island on 5 September 2003 are considered. Using a linearized model of atmospheric boundary layer flow over low-slope topography that also incorporates a model for changes of surface roughness, sets of directionally dependent wind speed adjustment factors were calculated for the island of Bermuda. These factors were then used in combination with a time-stepping model for the open water wind field of Hurricane Fabian derived from the Hurricane Research Division Real-Time Hurricane Wind Analysis System (H*Wind) surface wind analyses to calculate the maximum 1-min mean wind speed at locations across the island for the following conditions: open water, roughness changes only, and topography and roughness changes combined. Comparison of the modeled 1-min mean wind speeds and directions with observations from a site on the southeast coast of Bermuda showed good agreement between the two sets of values. Maximum open water wind speeds across the entire island showed very little variation and were of category 2 strength on the Saffir–Simpson scale. While the effects of surface roughness changes on the modeled wind speeds showed very little correlation with the observed damage, the effect of the underlying topography led to maximum modeled wind speeds of category 4 strength being reached in highly localized areas on the island. Furthermore, the observed damage was found to be very well correlated with these regions of topographically enhanced wind speeds, with a very clear trend of increasing damage with increasing wind speeds.

scholarly journals Model estimates hurricane wind speed probabilities

Eos ◽  
2000 ◽  
Vol 81 (38) ◽  
pp. 433 ◽  
Author(s):  
Richard J. Mumane ◽  
Chris Barton ◽  
Eric Collins ◽  
Jeffrey Donnelly ◽  
James Eisner ◽  
...  
Keyword(s):  
Wind Speed ◽  
Hurricane Wind

scholarly journals Wave Glider Observations of Surface Waves During Three Tropical Cyclones in the South China Sea

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1331 ◽  
Author(s):  
Di Tian ◽  
Han Zhang ◽  
Wenyan Zhang ◽  
Feng Zhou ◽  
Xiujun Sun ◽  
...  
Keyword(s):  
Surface Wave ◽  
South China Sea ◽  
Surface Waves ◽  
Tropical Cyclones ◽  
South China ◽  
Tangential Direction ◽  
China Sea ◽  
Wave Forecast ◽  
Wave Glider ◽  
The Right

Surface waves induced by tropical cyclones (TCs) play an important role in the air–sea interaction, yet are seldom observed. In the 2017 summer, a wave glider in the northern South China Sea successfully acquired the surface wave parameters when three TCs (Hato, Pakhar, and Mawar) passed though successively. During the three TCs, surface wave period increased from 4–6 s to ~8–10 s and surface wave height increased from 0–1 m to 3–8 m. The number of wave crests observed in a time interval of 1024 s decreased from 100–150 to 60–75. The sea surface roughness, a key factor in determining the momentum transfer between air and sea, increased rapidly during Hato, Pakhar, and Mawar. Surface waves rotated clockwise (anti-clockwise) on the right (left) side of the TC track, and generally propagated to the right side of the local cyclonic tangential direction relative to the TC center. The azimuthal dependence of the wave propagation direction is close to sinusoidal in a region within 50–600 km. The intersection angle between surface wave direction and the local cyclonic tangential direction is generally smallest in the right-rear quadrant of the TC and tends to be largest in the left-rear quadrant. This new set of glider wave observational data proves to be useful for assessing wave forecast products and for improvements in corresponding parameterization schemes.

scholarly journals An Assessment of the Climatology of Florida Hurricane-Induced Tornadoes (HITs): Technology versus Meteorology

2011 ◽  
Vol 24 (20) ◽  
pp. 5218-5222 ◽  
Author(s):  
Ernest M. Agee ◽  
Alyssa Hendricks
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Doppler Radar ◽  
Wind Damage ◽  
National Weather Service ◽  
Hurricane Wind ◽  
Data Archives ◽  
Tornado Damage ◽  
Weather Service

Abstract The placement of operational Doppler radar at National Weather Service offices in Florida in 1994 and 1995 has produced a distinct climatological discontinuity in archived records of hurricane-induced tornado (HIT) events. During the period of this study (1979–2010), Florida experienced 91 named tropical cyclones (omitting years 1994 and 1995) that produced a total of 300 HITs, as recorded in the NOAA Storm Data climatological publication. The 30 years of records examined for 1979–2010 consisted of 15 years as the pre-Doppler period (1979–93) and 15 years as the Doppler period (1996–2010) and produced an average of 1.92 HITs per tropical cyclone for the pre-Doppler period and 3.85 HITs per tropical cyclone for the Doppler period. Additionally, the HIT statistics were further compiled as the number of HITs per potential HIT day, which yielded values of 0.52 and 1.14, respectively, for the pre-Doppler and Doppler periods. Normalized statistics are based on the total accumulated number of potential HIT days for each period (96 for pre-Doppler and 219 for Doppler). Further, it has been determined that (a) no HITs were recorded in the pre-Doppler period for hurricanes greater than category-2 intensity, ostensibly because of the inability to separate hurricane wind damage from tornado damage, whereas (b) the Doppler period averaged 5.0 and 11.7 HITs per category-3 and category-4 storms, respectively. Finally, this study has clearly documented the magnitude (and effect) of Doppler technology on HITs reported in Florida Storm Data archives. The Doppler era is much more accurate, whereas the pre-Doppler era HIT occurrences are severely underestimated.

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