Estimating the Key Parameter of a Tropical Cyclone Wind Field Model over the Northwest Pacific Ocean: A Comparison between Neural Networks and Statistical Models

Estimation of maximum wind speed associated with tropical cyclones (TCs) is crucial to evaluate potential wind destruction. The Holland B parameter is the key parameter of TC parametric wind field models. It plays an essential role in describing the radial distribution characteristics of a TC wind field and has been widely used in TC disaster risk evaluation. In this study, a backpropagation neural network (BPNN) is developed to estimate the Holland B parameter (Bs) in TC surface wind field model. The inputs of the BPNN include different combinations of TC minimum center pressure difference (Δp), latitude, radius of maximum wind speed, translation speed and intensity change rate from the best-track data of the Joint Typhoon Warning Center (JTWC). We find that the BPNN exhibits the best performance when only inputting TC central pressure difference. The Bs estimated from BPNN are compared with those calculated from previous statistical models. Results indicate that the proposed BPNN can describe well the nonlinear relation between Bs and Δp. It is also found that the combination of BPNN and Holland’s wind pressure model can significantly improve the maximum wind speed underestimation and overestimation of the two existing wind pressure models (AH77 and KZ07) for super typhoons.

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Analysis of Boundary Layer Wind Field Statistical Characteristics and Reference Wind Pressure in Wenzhou District

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.1424 ◽

2011 ◽

Vol 368-373 ◽

pp. 1424-1430

Author(s):

Jian Jia Wu ◽

Wen Hai Shi

Keyword(s):

Wind Speed ◽

Wind Field ◽

Wind Pressure ◽

Maximum Wind Speed ◽

Statistical Characteristics ◽

Annual Maximum ◽

Maximum Wind ◽

Wind Speed Maximum ◽

Mean Wind Speed ◽

Extreme Wind Speed

Based on large amount of meteorological wind field records observed in Wenzhou district, this paper analyzed the annual maximum wind speed (maximum 10 minute mean wind speed), annual extreme wind speed (maximum 3 seconds mean wind speed), reference wind pressure and wind field characteristics of typhoon in Wenzhou. The results shows that the annual maximum wind speed have a decreased trend on the whole in different areas of Wenzhou, and the trend in coastal area is more obvious than that in inland areas; the annual maximum wind speed in different areas of Wenzhou is unsteady and the typhoons have great effect on it; the value of reference wind pressure in Dongtou is greater than the value given by the design load code of China (GB50009-2001, 2002), but the values of other areas are less than the value of Code. Based on the wind field of three typhoon records, some significant results about the variation and routine characteristics of typhoon are also discussed.

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Application of SAR Data for Tropical Cyclone Intensity Parameters Retrieval and Symmetric Wind Field Model Development

Remote Sensing ◽

10.3390/rs13152902 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2902

Author(s):

Yuan Gao ◽

Jie Zhang ◽

Jian Sun ◽

Changlong Guan

Keyword(s):

Wind Speed ◽

Wind Field ◽

Maximum Wind Speed ◽

Wind Fields ◽

Maximum Wind ◽

Wind Field Model ◽

Wind Speeds ◽

Central Surface ◽

Intensity Parameters ◽

Wind Retrievals

The spaceborne synthetic aperture radar (SAR) is an effective tool to observe tropical cyclone (TC) wind fields at very high spatial resolutions. TC wind speeds can be retrieved from cross-polarization signals without wind direction inputs. This paper proposed methodologies to retrieve TC intensity parameters; for example, surface maximum wind speed, TC fullness (TCF) and central surface pressure from the European Space Agency Sentinel-1 Extra Wide swath mode cross-polarization data. First, the MS1A geophysical model function was modified from 6 to 69 m/s, based on three TC samples’ SAR images and the collocated National Oceanic and Atmospheric Administration stepped frequency microwave radiometer wind speed measurements. Second, we retrieved the wind fields and maximum wind speeds of 42 TC samples up to category 5 acquired in the last five years, using the modified MS1A model. Third, the TCF values and central surface pressures were calculated from the 1-km wind retrievals, according to the radial curve fitting of wind speeds and two hurricane wind-pressure models. Three intensity parameters were found to be dependent upon each other. Compared with the best-track data, the averaged bias, correlation coefficient (Cor) and root mean-square error (RMSE) of the SAR-retrieved maximum wind speeds were –3.91 m/s, 0.88 and 7.99 m/s respectively, showing a better result than the retrievals before modification. For central pressure, the averaged bias, Cor and RMSE were 1.17 mb, 0.77 and 21.29 mb and respectively, indicating the accuracy of the proposed methodology for pressure retrieval. Finally, a new symmetric TC wind field model was developed with the fitting function of the TCF values and maximum wind speeds, radial wind curve and the Rankine Vortex model. By this model, TC wind field can be simulated just using the maximum wind speed and the radius of maximum wind speed. Compared with wind retrievals, averaged absolute bias and averaged RMSE of all samples’ wind fields simulated by the new model were smaller than those of the Rankine Vortex model.

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A Hurricane Boundary Layer and Wind Field Model for Use in Engineering Applications

Journal of Applied Meteorology and Climatology ◽

10.1175/2008jamc1841.1 ◽

2009 ◽

Vol 48 (2) ◽

pp. 381-405 ◽

Cited By ~ 152

Author(s):

Peter J. Vickery ◽

Dhiraj Wadhera ◽

Mark D. Powell ◽

Yingzhao Chen

Keyword(s):

Boundary Layer ◽

Wind Speed ◽

Drag Coefficient ◽

Wind Field ◽

Field Model ◽

Radial Dependence ◽

Surface Winds ◽

Wind Field Model ◽

Wind Speeds ◽

Hurricane Boundary Layer

Abstract This article examines the radial dependence of the height of the maximum wind speed in a hurricane, which is found to lower with increasing inertial stability (which in turn depends on increasing wind speed and decreasing radius) near the eyewall. The leveling off, or limiting value, of the marine drag coefficient in high winds is also examined. The drag coefficient, given similar wind speeds, is smaller for smaller-radii storms; enhanced sea spray by short or breaking waves is speculated as a cause. A fitting technique of dropsonde wind profiles is used to model the shape of the vertical profile of mean horizontal wind speeds in the hurricane boundary layer, using only the magnitude and radius of the “gradient” wind. The method slightly underestimates the surface winds in small but intense storms, but errors are less than 5% near the surface. The fit is then applied to a slab layer hurricane wind field model, and combined with a boundary layer transition model to estimate surface winds over both marine and land surfaces.

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Comments on “Reexamination of Tropical Cyclone Wind–Pressure Relationship”

Weather and Forecasting ◽

10.1175/2008waf2007068.1 ◽

2008 ◽

Vol 23 (4) ◽

pp. 758-761 ◽

Cited By ~ 2

Author(s):

Shyamnath Veerasamy

Keyword(s):

Wind Speed ◽

Tropical Cyclones ◽

North Atlantic ◽

Wind Pressure ◽

Maximum Wind Speed ◽

Central Pressure ◽

Southwest Indian Ocean ◽

Maximum Wind ◽

The North ◽

The North Atlantic

Abstract In their study on the wind–pressure relationship (WPR) that exists in tropical cyclones, Knaff and Zehr presented results of the use of the Dvorak Atlantic WPR for estimating central pressure and maximum wind speed of tropical cyclones. These show some fairly large departures of estimated central pressure and maximum surface winds from observed values. Based on a study carried out in the southwest Indian Ocean (SWIO), it is believed that improvements in the use of the Dvorak WPR can be achieved by using the size of a closed isobar (it is the 1004-hPa closed isobar in the SWIO) to determine whether to use the North Atlantic (NA), the western North Pacific (WNP), or a mean of the NA and WNP Dvorak WPR for estimating central pressure and maximum wind speed in tropical cyclones.

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Comparative assessment of validity of gradient wind models for a translating tropical cyclone

SN Applied Sciences ◽

10.1007/s42452-021-04406-w ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Yuzuru Eguchi ◽

Yasuo Hattori ◽

Mitsuharu Nomura

Keyword(s):

Wind Speed ◽

Tropical Cyclone ◽

Wind Field ◽

Comparative Assessment ◽

Maximum Wind Speed ◽

Observation Data ◽

High Wind ◽

Maximum Wind ◽

Gradient Wind ◽

The Difference

AbstractAccurate and conservative evaluations of the gradient wind in the free atmosphere are needed to account for high-wind hazards when designing wind resistance for critical infrastructure. This paper compared the validity of three existing gradient wind models to select an appropriate evaluation model, which enables us to accurately compute the asymmetric gradient wind field of a translating tropical cyclone under the condition of a symmetric pressure distribution and a constant translation velocity. The validity of the three models was assessed by evaluating the residuals in momentum conservation equations for the gradient wind under a specific tropical cyclone condition. The magnitude of the residuals was considered to be the measure of error in the gradient wind derived from each model. The results showed that the most frequently used model yielded the largest magnitude of residuals with the lowest maximum wind speed among the three models. The wind characteristics of the three models were validated using archived observation data of hurricanes. The physical reason for the difference in maximum wind speed among the three models was explained by the difference in the streamline feature of the gradient wind field. It was also revealed that the differences in maximum wind speed and magnitude of residuals became more pronounced as the translation speed and the intensity of a tropical cyclone increased. The comparative assessment of the three gradient wind models allowed us to identify the best model for use in conservative wind-resistant design and high-wind risk estimates.

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The Effect of the Surface Wind Field Representation in the Operational Storm Surge Model of the National Hurricane Center

Atmosphere ◽

10.3390/atmos10040193 ◽

2019 ◽

Vol 10 (4) ◽

pp. 193 ◽

Cited By ~ 4

Author(s):

Talea Mayo ◽

Ning Lin

Keyword(s):

Wind Speed ◽

Storm Surge ◽

Wind Field ◽

Wind Profile ◽

Storm Surges ◽

Maximum Wind Speed ◽

Field Representation ◽

Maximum Wind ◽

National Hurricane Center ◽

Surface Background

The Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is the operational storm surge model of the National Hurricane Center (NHC). Previous studies have found that the SLOSH model estimates storm surges with an accuracy of ±20%. In this study, through hindcasts of historical storms, we assess the accuracy of the SLOSH model for four coastal regions in the Northeastern United States. We investigate the potential to improve this accuracy through modification of the wind field representation. We modify the surface background wind field, the parametric wind profile, and the maximum wind speed based on empirical, physical, and observational data. We find that on average the SLOSH model underestimates maximum storm surge heights by 22%. The modifications to the surface background wind field and the parametric wind profile have minor impacts; however, the effect of the modification to maximum wind speed is significant—it increases the variance in the SLOSH model estimates of maximum storm surges, but improves its accuracy overall. We recommend that observed values of maximum wind speed be used in SLOSH model simulations when possible.

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