Hurricane Eye Research Articles

Geostationary Satellite–Derived Positioning of a Tropical Cyclone Center Using Artificial Intelligence Algorithms over the Western North Pacific

Abstract Artificial intelligence (AI) models were developed to determine the center of tropical cyclones (TCs) in the western North Pacific. These models integrated information from six channels of geostationary satellite imagery: the brightness temperature of four infrared (IR) and one shortwave IR channels, as well as the reflectivity of one visible channel. The first model is a convolutional neural network designed for spatial data processing, and the second is a convolutional long short-term memory model that effectively captures spatiotemporal information. For training, verification, and testing purposes, spatial images from six channels were obtained from the Japanese Himawari-8 satellite from 2016 to 2021. The position of the European Centre for Medium-Range Weather Forecasts 6- or 12-h prediction was assigned as an initial value to the AI models. Errors in the initial value were 20–50 km compared to the Joint Typhoon Warning Center best track, depending on TC intensity. Weak (strong) TCs exhibited large (small) errors. This error dependency was found in Automated Rotational Center Hurricane Eye Retrieval (ARCHER) product, which is currently used by several operational organizations. ARCHER errors were typically small when observations from both geostationary and polar-orbiting satellites were included. Significant errors remained in the absence of microwave channel information from polar-orbiting satellites. This study successfully developed two AI models that consistently determined the location of the TC center using only six-channel images from geostationary satellites. These models exhibited comparable or better performance than the ARCHER products. The newly developed AI models can potentially be implemented for operational use.

Detection and Three‐Dimensional Reconstruction of Concentric Traveling Ionosphere Disturbances Induced by Hurricane Matthew on 7 October 2016

AbstractThis paper reports the first high‐resolution 4‐dimensional ionospheric disturbance caused by hurricane Matthew on 7 October 2016. The temporal as well as vertical and horizontal variations of the concentric traveling ionospheric disturbances (CTIDs) were reconstructed using 3‐dimensional computerized ionospheric tomography (3DCIT) technology, based upon the Global Navigation Satellite System data from the dense receiver network over North America. The frequency range of disturbances was determined by spectrum analysis, and a Butterworth band‐pass filter was used to de‐trend the total electron content (TEC) sequences to determine TIDs. A remarkable CTID segment was detected at a distance of 1,000–1,500 km from the hurricane eye at ∼5:40–6:10 UT on 7 October 2016, moving westward with the horizontal phase velocity of ∼153.4 m/s, the period of ∼30 min and the horizontal wavelength of ∼276.1 km. The positive and negative wavefronts dominated the CITD at different times during the event. From 4:00 to 8:00 UT, the altitudinal variation of the CTIDs in electron density exhibited clear downward phase progression predominately in the range of 150–400 km altitudes; however, the percentage of electron density disturbances was larger below 250 km. The inverted cone‐like geometry of CTID wavefronts was presented. The vertical phase velocities of the CTIDs ∼1,100 km away from the hurricane eye in the northwest direction near 88°W, 34°N were ∼203.7–277.8 m/s, and at the same location, the horizontal phase velocities at 300 km altitude were ∼149.1–181.5 m/s, slightly larger than those at 200 km altitude (∼145.1–178.5 m/s).

The basic wind characteristics of idealized hurricanes of different intensity levels

In the current study, we conducted four idealized hurricane simulation cases to investigate the basic wind characteristics of hurricanes at different sea surface temperatures. First, the relationship of the minimum of sea surface pressure and the maximum of time-averaged wind speed shows good agreement with observational data and theoretical considerations. Then, the tangential, radial, and vertical wind field are analyzed, both the value and the height of the maximum tangential wind increase with increasing sea surface temperature. The peak value and the height of radial inflow also increase with sea surface temperature increases. An important feature is for the depth of the inflow layer, which always increases for weak hurricanes and beginning increases then decreases for intense hurricanes locates from hurricane eye to three times radius of maximum wind, this can also be seen in hurricane observation data. More importantly, this is the first study that found it begins to increase then becomes steady for medium-strength hurricanes. Furthermore, extreme updrafts are found for intense hurricanes, while not for weak and medium-strength hurricanes, and this also shows good agreement between the observational and simulation data, which is related to coherent subkilometer-scale vortices. Also, the average surface inflow angle is −22.1°, similar to −22.6° ± 2.2° and −23° that are obtained in other studies, and the distribution of surface inflow angle displays good agreement with previous studies. The relationship of tangential velocity and radial velocity is similar to the shape of a tilted infinity symbol. Finally, by analyzing the fluctuating wind characteristics, a 200 m grid size is sufficient except for the weak hurricane, which requires a 62 m grid size for turbulence structures. From the relationship of mean and fluctuating wind characteristics, the hurricane simulation results of different intensity levels converged for 185 m and 62 m grid size.

Comparison of ARCHER MPERC to NHC Analysis

Eyewall replacement cycles (ERCs) are events that occur in intense tropical cyclones (TCs) and are difficult to predict. An ERC event involves a secondary outer eyewall that surrounds the inner eyewall. The outer eyewall slowly moves towards the eye and weakens the inner eyewall, eventually replacing the inner eyewall. During this process, wind speeds lower and the structure of a TC becomes disorganized, further weakening the storm. TCs often restrengthen after an ERC. Little is known about the process and as such, poses an obstacle to forecasters. The Automated Rotational Center Hurricane Eye Retrieval (ARCHER) Microwave-based Probability of Eyewall Replacement Cycle (MPERC) is an algorithm that uses 89-95 GHz passive microwave imagery and intensity estimates from the National Hurricane Center (NHC), Central Pacific Hurricane Center (CPHC), or the Joint Typhoon Warning Center (JTWC) to predict the possibility of an ERC. The effectiveness and ability of ARCHER MPERC was analyzed and compared to the NHC’s official reports on all Atlantic Basin tropical cyclones from 2017 to 2019. MPERC ultimately predicted seventeen ERCs in nine tropical cyclones. Of those, seven were valid ERCs. The algorithm works well, predicting approximately 41% of the total number of predictions correctly. However, MPERC did not predict five ERCs that were cited by the NHC. It was further found that it was true that MPERC produces incorrect results in sheared and dry environments.

Understanding the Effects of Wind Intensity, Forward Speed, Pressure and Track on Generation and Propagation of Hurricane Irma Surges around Florida

In this study, it is demonstrated that hurricane wind intensity, forward speed, pressure, and track play an important role on the generation and propagation of coastal storm surges. Hurricane Irma, which heavily impacted the entire Florida peninsula in 2017, is used to study the storm surge sensitivity to varying storm characteristics. Results show that the west coast experiences a negative surge due to offshore wind of the approaching storm, but the positive surge returns after the hurricane eye passes over a location and wind became onshore. In the west coast peak, surges are intensified by an increase in onshore wind intensity and forward speed. In the Florida Keys, peak surges are intensified by an increase in wind intensity, a decrease in forward speed and a decrease in pressure. In southeast and east Florida, peak surges are intensified by decrease in pressure, although overall surges are less significant as the water can slide along the coastline. In the recessed coastline of Georgia-Carolinas, maximum surge is elevated by an increase in onshore wind intensity. Shifting the track westward increases peak surges on the west coast, while shifting the track eastward increases peak surge on the east coast. The results demonstrate a new understanding about the sensitivity of surge to varying parametric conditions and the importance of considering changes in the coastline orientation in storm surge predictions.

Hurricane eye morphology extraction from SAR images by texture analysis

Hurricane eye morphology extraction from SAR images by texture analysis

Evaluation of parametric wind models for more accurate modeling of storm surge: a case study of Hurricane Michael

Storm surge induced by hurricane is a major threat to the Gulf Coasts of the United States. A numerical modeling study was conducted to simulate the storm surge during Hurricane Michael, a category 5 hurricane that landed on the Florida Panhandle in 2018. A high-resolution model mesh was used in the ADCIRC hydrodynamic model to simulate storm surge and tides during the hurricane. Two parametric wind models, Holland 1980 model and Holland 2010 model, have been evaluated for their effects on the accuracy of storm surge modeling by comparing simulated and observed maximum water levels along the coast. The wind model parameters are determined by observed hurricane wind and pressure data. Results indicate that both Holland 1980 and Holland 2010 wind models produce reasonable accuracy in predicting maximum water level in Mexico Beach, with errors between 1 and 3.7%. Comparing to the observed peak water level of 4.74 m in Mexico Beach, Holland 1980 wind model with radius of 64-knot wind speed for parameter estimation results in the lowest error of 1%. For a given wind model, the wind profiles are also affected by the wind data used for parameter estimation. Away from hurricane eye wall, using radius of 64-knot wind speed for parameter estimation generally produces weaker wind than those using radius of 34-knot wind speed for parameter estimation. Comparing model simulated storm tides with 17 water marks observed along the coast, Holland 2010 wind model using radius of 34-knot wind speed for parameter estimation leads to the minimum mean absolute error. The results will provide a good reference for researchers to improve storm surge modeling. The validated model can be used to support coastal hazard mitigation planning.

Improved Climatology of Tropical Cyclone Precipitation from Satellite Passive Microwave Measurements

AbstractAccurate precipitation climatology is presented for tropical depression (TD), tropical storm (TS), and tropical cyclone (TC) over oceans using the recently-released, consistent and high quality precipitation datasets from all passive microwave sensors covering 1998-2012 along with the Automated Rotational Center Hurricane Eye Retrieval (ARCHER)-based TC center positions. Impacts with respect to the direction of both TC movement and the 200-850 hPa wind shear on the spatial distributions of TC precipitation are analyzed. The TC eyewall contraction process during its intensification is noted by a decrease in the radius of maximum rainrate with an increase in TC intensity. For global TCs, the maximum rainrate with respect to the direction of TC movement is located in the down-motion quadrants for TD, TS, and Cat 1-3 TCs, and in a concentric pattern for Cat 4-5 TCs. A consistent maximum TC precipitation with respect to the direction of the 200-850 hPa wind shear is shown in the down shear left quadrant (DSLQ). With respect to direction of TC movement, spatial patterns of TC precipitation vary with basins and show different features for weak and strong storms. The maximum rainrate is always located in DSLQ for all TC categories and basins, except the Southern Hemisphere basin where it is in the down shear right quadrant (DSRQ). This study not only confirms previously published results on TC precipitation distributions relative to vertical wind shear direction, but also provides a detailed distribution for each TC category and TS, while TD storms display an enhanced rainfall rate ahead of the down shear quadrants.

Evaluating the accuracy and uncertainty of atmospheric and wave model hindcasts during severe events using model ensembles

Various uncertainties exist in a hindcast due to the inabilities of numerical models to resolve all the complicated atmosphere-sea interactions, and the lack of certain ground truth observations. Here, a comprehensive analysis of an atmospheric model performance in hindcast mode (Hurricane Weather and Research Forecasting model—HWRF) and its 40 ensembles during severe events is conducted, evaluating the model accuracy and uncertainty for hurricane track parameters, and wind speed collected along satellite altimeter tracks and at stationary source point observations. Subsequently, the downstream spectral wave model WAVEWATCH III is forced by two sets of wind field data, each includes 40 members. The first ones are randomly extracted from original HWRF simulations and the second ones are based on spread of best track parameters. The atmospheric model spread and wave model error along satellite altimeters tracks and at stationary source point observations are estimated. The study on Hurricane Irma reveals that wind and wave observations during this extreme event are within ensemble spreads. While both Models have wide spreads over areas with landmass, maximum uncertainty in the atmospheric model is at hurricane eye in contrast to the wave model.

The NASA‐JAXA Global Precipitation Measurement mission – part II: New frontiers in precipitation science

The <scp>NASA‐JAXA</scp> Global Precipitation Measurement mission – part <scp>II</scp>: New frontiers in precipitation science

Tropical Cyclone Climatology from Satellite Passive Microwave Measurements

The satellite passive microwave (PMW) sensor brightness temperatures (TBs) of all tropical cyclones (TCs) from 1987–2012 have been carefully calibrated for inter-sensor frequency differences, center position fixing using the Automated Rotational Center Hurricane Eye Retrieval (ARCHER) scheme, and application of the Backus–Gilbert interpolation scheme for better presentation of the TC horizontal structure. With additional storm motion direction and the 200–850 hPa wind shear direction, a unique and comprehensive TC database is created for this study. A reliable and detailed climatology for each TC category is analyzed and discussed. There is significant annual variability of the number of storms at hurricane intensity, but the annual number of all storms is relatively stable. Results based on the analysis of the 89 GHz horizontal polarization TBs over oceans are presented in this study. An eyewall contraction is clearly displayed with an increase in TC intensity. Three composition schemes are applied to present a reliable and detailed TC climatology at each intensity category and its geographic characteristics. The global composition relative to the North direction is not able to lead a realistic structure for an individual TC. Enhanced convection in the down-motion quadrants relative to direction of TC motion is obvious for Cat 1–3 TCs, while Cat 4–5 TCs still have a concentric pattern of convection within 200 km radius. Regional differences are evident for weak storms. Results indicate the direction of TC movement has more impact on weak storms than on Cat 4–5 TCs. A striking feature is that all TCs have a consistent pattern of minimum TBs at 89 GHz in the downshear left quadrant (DSLQ) for the northern hemisphere basins and in the downshear right quadrant (DSRQ) for the southern hemisphere basin, regarding the direction of the 200–850 hPa wind shear. Tropical depression and tropical storm have the minimum TBs in the downshear quadrants. The axis of the minimum TBs is slightly shifted toward the vertical shear direction. There is no geographic variation of storm structure relative to the vertical wind shear direction except over the southern hemisphere which shows a mirror image of the storm structure over the northern hemisphere. This study indicates that regional variation of storm structure relative to storm motion direction is mainly due to differences of the vertical wind shear direction among these basins. Results demonstrate the direction of the 200–850 hPa wind shear plays a critical role in TC structure.

Comparison of Tropical Cyclone Center Positions Determined from Satellite Observations at Infrared and Microwave Frequencies

AbstractDetermining tropical cyclone (TC) center positions is of interest to many researchers who conduct TC analysis and forecasts. In this study, we develop and apply a TC centering technique to Cross-Track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) observations of brightness temperature and report on an improvement of accuracy by adding a TC spectral analysis to the state of the art [Automated Rotational Center Hurricane Eye Retrieval (ARCHER)], especially for ATMS. We show that the ARCHER TC center-fixing algorithm locates TC centers more successfully based on the infrared channel with center frequency at 703.75 cm−1 (channel 89) of the CrIS than the ATMS channel 22 (183.31 ± 1.0 GHz) due to small-scale features in ATMS channel’s brightness temperature field associated with strong convective clouds. We propose to first apply the ARCHER TC center-fixing algorithm to ATMS channel 4 (51.76 GHz) that is less affected by small-scale convective clouds, and then to perform a set of the azimuthal spectral analysis of the ATMS channel-22 observations with tryout centers within a squared box centered at the ATMS channel-4-determined center. The center that gives the largest symmetric component is the final ATMS-determined center. Compared to the National Hurricane Center best track, the root-mean-square center-fixing errors determined from the two ATMS channels (one single CrIS channel) are 29.9 km (35.8 km) and 28.0 km (30.9 km) for 104 tropical storm and 81 hurricane cases, respectively, in the 2019 hurricane season.

Structured CT reporting improves accuracy in diagnosing internal herniation after laparoscopic Roux-en-Y gastric bypass

ObjectivesTo confirm that structured reporting of CT scans using ten signs in clinical practice leads to a better accuracy in diagnosing internal herniation (IH) after gastric bypass surgery, compared with free-text reporting.MethodsIn this prospective study, CT scans between June 1, 2017, and December 1, 2018, were included from a cohort of 2606 patients who had undergone laparoscopic gastric bypass surgery between January 1, 2011, and January 1, 2018. The CT scans were made for a suspicion of IH and structured reports were made using a standardised template with ten signs: (1) swirl sign, (2) small-bowel obstruction, (3) clustered loops, (4) mushroom sign, (5) hurricane eye sign, (6) small bowel behind the superior mesenteric artery, (7) right-sided anastomosis, (8) enlarged nodes, (9) venous congestion, and (10) mesenteric oedema. Furthermore, an overall impression of IH likelihood was given using a 5-point Likert scale. CT scans performed in 2011 until 2017, without structured reporting, were included for comparison. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated using two-way contingency tables; the chi-square test was used for calculating p value. Reoperation and 3-month follow-up were used as reference.ResultsA total of 174 CT scans with structured reporting and 289 CT scans without structured reporting were included. Sensitivity was 81.3% (95% CI, 67.7–94.8%) and 79.5% (95% CI, 67.6–91.5%), respectively (p = 0.854); specificity was 95.8% (95% CI, 92.5–99.1%) and 88.6% (95% CI, 84.6–92.6%), respectively (p = 0.016); PPV was 81.3% (95% CI, 67.7–94.8%) and 55.6% (95% CI, 43.3–67.8%), respectively (p = 0.014); NPV was 95.8% (95% CI, 92.5–99.1%) and 96.0% (95% CI, 93.5–98.6%), respectively (p = 0.909); and accuracy was 93.1% (95% CI, 88.0–96.2%) and 87.2% (95% CI, 82.7–90.7%), respectively (p = 0.045).ConclusionStructured reporting for the diagnosis of internal herniation after gastric bypass surgery improves accuracy and can be implemented in clinical practice with good results.Key Points• Ten signs are used to aid CT diagnosis of internal herniation after gastric bypass surgery.• Structured reporting increases specificity and positive predictive value and thereby prevents unnecessary reoperations in patients without internal herniation.• Structured reporting by means of a standardised template can help less experienced readers.

Simulating tropical storms in the Gulf of Mexico using analytical models

SUMMARY Different analytical models have been evaluated for estimating wind speed of the tropical storm, where the storm-induced wind velocity is calculated as a function of distance from the center of the hurricane. For these models, different parameters such as maximum wind speed, a radius of the maximum wind, hurricane shape parameter, hurricane translation speed and the orientation of the trajectory, etc., affect the shape of a hurricane. Hurricanes Lili (2002), Ivan (2004), Katrina (2005), Gustav (2008) and Ike (2008) from the Gulf of Mexico were used for skill assessment. The maximum wind radius was calculated using significant wind radii (R34, R50 and R64) reported by the National Hurricane Center. Different formulas for calculating the radius of maximum wind speed were evaluated. The asymmetric wind field for each hurricane was generated using analytic methods and compared with in situ data from buoys in the Gulf of Mexico and the H*Wind data. Analytical models were able to predict high wind speed under tropical cyclone conditions with relatively high precision. Among the analytical models evaluated in this research, the model proposed by Holland et al. (2010) showed excellent results. Dynamical wind models such as NCEP/NARR provide wind speed with the coarse spatial resolution which is acceptable for far-field locations away from the hurricane eye. In contrast, analytical models were able to produce sufficiently reliable wind speed within a particular radius from the center of the hurricane. Therefore blending of dynamical and analytical models can be used to provide accurate wind data during hurricane passage in the Gulf of Mexico.

A new technique for automatically locating the center of tropical cyclones with multi-band cloud imagery

A spiral cloud belt matching (SCBeM) technique is proposed for automatically locating the tropical cyclone (TC) center position on the basis of multi-band geo-satellite images. The technique comprises four steps: fusion of multi-band geo-satellite images, extraction of TC cloud systems, construction of a spiral cloud belt template (CBT), and template matching to locate the TC center. In testing of the proposed SCBeM technique on 97 TCs over the western North Pacific during 2012–2015, the median error (ME) was 50 km. An independent test of another 29 TCs in 2016 resulted in a ME of 54 km. The SCBeM performs better for TCs with intensity above “typhoon” level than it does for weaker systems, and is not suitable for use on high-latitude or landfall TCs if their cloud band formations have been destroyed by westerlies or by terrain. The proposed SCBeM technique provides an additional solution for automatically and objectively locating the TC center and has the potential to be applied conveniently in an operational setting. Intercomparisons between the Automated Rotational Center Hurricane Eye Retrieval (ARCHER) and SCBeM methods using events from 2014 to 2016 reveal that ARCHER has better location accuracy. However, when IR imagery alone is used, the ME of SCBeM is 54 km, and in the case of low latitudes and low vertical wind shear the ME is 45–47 km, which approaches that of ARCHER (49 km). Thus, the SCBeM method is simple, has good time resolution, performs well and is a better choice for those TC operational agencies in the case that the microwave images, ASCAT, or other observations are unavailable.

A new stochastic formulation for synthetic hurricane simulation over the North Atlantic Ocean

Hurricanes are among the most destructive weather phenomena in the United States (US) of America. Accurate modeling of hurricane trajectories, as they land ashore and approach the built environment, is important for public safety. This study presents a new stochastic model for the simulation of hurricane trajectories in the North Atlantic Ocean. Trajectory of the hurricane eye is modeled as a two-dimensional partially-correlated Brownian motion with drift term. Hurricane intensity is modeled as a second-order auto-regressive process, accounting for sea surface temperature.The model is validated by comparing the numerically-generated hurricane tracks against historical records, derived from the HurDat database (NOAA, National Oceanic and Atmospheric Administration). Simulated hurricane arrival and landing rates along the US Eastern coastline are also examined to demonstrate model validity. Finally, performance-based wind engineering (PBWE) application is presented by comparing simulated hurricane wind speeds against ASCE 7-16 recommendations.

In the Hurricane's Eye: The Genius of George Washington and the Victory at Yorktown

In the Hurricane's Eye: The Genius of George Washington and the Victory at Yorktown

Tropical Cyclone Center Fix Using CYGNSS Winds

AbstractA new method is described for determining the center location of a tropical cyclone (TC) using wind speed measurements by the NASA Cyclone Global Navigation Satellite System (CYGNSS). CYGNSS measurements made during TC overpasses are used to constrain a parametric wind speed model in which storm center location is varied. The “MTrack” storm center location is selected to minimize the residual difference between model and measurement. Results of the MTrack center fix are compared to the National Hurricane Center (NHC) Best Track, the Automated Rotational Center Hurricane Eye Retrieval (ARCHER), and aircraft reconnaissance fixes for category 1–category 3 TCs during the 2017 and 2018 hurricane seasons. MTrack produces storm center locations at intermediate times between NHC fixes with a factor of 5.6 overall reduction in sensitivity to uncertainties in the NHC fixes between which it interpolates. The MTrack uncertainty is found to be larger in the cross-track direction than the along-track direction, although this behavior and the absolute accuracy of position estimates require further investigation.

A New Hurricane Wind Direction Retrieval Method for SAR Images without Hurricane Eye

AbstractThis study presents a new approach for hurricane wind direction retrieval utilizing rainband streaks contained in synthetic aperture radar (SAR) images without hurricane eye information, based on the hurricane inflow angle. To calculate the wind direction field, a method for estimating the location of the hurricane center is given. In this paper, four Sentinel-1A (S-1A) images with a hurricane eye are used to clarify the center estimation method. Three S-1A SAR images without a hurricane eye are studied to evaluate the accuracy of the new method. The estimated locations of hurricane centers show good agreement with hurricane track data provided by the National Oceanic and Atmospheric Administration (NOAA)’s Atlantic Oceanographic and Meteorological Laboratory (AOML) Hurricane Research Division (HRD), HurricaneCity, and the National Institute of Informatics (NII). To validate the estimated wind directions, the NOAA HRD dropwindsonde observations for Tropical Storm Karl are collected and compared. The wind directions retrieved by our approach are more consistent with visual inspection than the fast Fourier transform (FFT) method in subimages. Moreover, the retrieved wind speeds utilizing C-band model 5.N (CMOD5.N) are compared with wind speed estimations observed by Stepped Frequency Microwave Radiometer (SFMR). The results suggest that the proposed method has good potential to retrieve hurricane wind direction from SAR images without a hurricane eye and external data.

A Global Climatology of Tropical Cyclone Eyes

Abstract Intense tropical cyclones (TCs) generally produce a cloud-free center with calm winds, called the eye. The Automated Rotational Center Hurricane Eye Retrieval (ARCHER) algorithm is used to analyze Hurricane Satellite (HURSAT) B1 infrared satellite imagery data for storms occurring globally from 1982 to 2015. HURSAT B1 data provide 3-hourly observations of TCs. The result is a 34-yr climatology of eye location and size. During that time period, eyes are identified in about 13% of all infrared images and slightly more than half of all storms produced an eye. Those that produce an eye have (on average) 30 h of eye scenes. Hurricane Ioke (1992) had the most eye images (98, which is 12 complete days with an eye). The median wind speed of a system with an eye is 97 kt (50 m s−1) [cf. 35 kt (18 m s−1) for those without an eye]. Eyes are much more frequent in the Northern Hemisphere (particularly in the western Pacific) but eyes are larger in the Southern Hemisphere. The regions where eyes occur are expanding poleward, thus expanding the area at risk of TC-related damage. Also, eye scene occurrence can provide an objective measure of TC activity in place of those based on maximum wind speeds, which can be affected by available observations and forecast agency practices.