Geomorphologic Recovery of North Captiva Island from the Landfall of Hurricane Charley in 2004

Hurricane Charley made landfall on the Gulf Coast of Florida on 13 August 2004 as a category 4 hurricane, devastating North Captiva Island. The hurricane caused a breach to occur to the southern end of the island, which naturally healed itself over the course of three years. By 2008, the cut was completely repaired geomorphologically. LiDAR data analysis shows the northern half of the island has been subjected to persistent erosion from 1998–2018, while the southern half experienced accretion since 2004, including the complete closure of the “Charley cut”. The maximum volume of sediment erosion in the northern sector of the island (R71–R73) from 2004–2018 was −85,710.1 m3, which was the source of southern accretion. The breached area of the island (R78b–R79a) obtained 500,163.9 m3 of sediments from 2004–2018 to heal the cut made by Hurricane Charley. Along with LiDAR data analysis, Google Earth Pro historical imageries and SANDS volumetric analysis confirmed the longshore transport of sediments from the northern to the southern end of the island. Winter storms are mainly responsible for this southerly longshore transport and are hypothesized to be the main factor driving the coastal dynamics that restored the breach and helps in widening the southern end of North Captiva Island.

A Rapid Forecasting and Mapping System of Storm Surge and Coastal Flooding

A prototype of an efficient and accurate rapid forecasting and mapping system (RFMS) of storm surge is presented. Given a storm advisory from the National Hurricane Center, the RFMS can generate a coastal inundation map on a high-resolution grid in 1 min (reference system Intel Core i7–3770K). The foundation of the RFMS is a storm surge database consisting of high-resolution simulations of 490 optimal storms generated by a robust storm surge modeling system, Curvilinear-Grid Hydrodynamics in 3D (CH3D-SSMS). The RFMS uses an efficient quick kriging interpolation scheme to interpolate the surge response from the storm surge database, which considers tens of thousands of combinations of five landfall parameters of storms: central pressure deficit, radius to maximum wind, forward speed, heading direction, and landfall location. The RFMS is applied to southwest Florida using data from Hurricane Charley in 2004 and Hurricane Irma in 2017, and to the Florida Panhandle using data from Hurricane Michael in 2018 and validated with observed high water mark data. The RFMS results agree well with observation and direct simulation of the high-resolution CH3D-SSMS. The RFMS can be used for real-time forecasting during a hurricane or “what-if” scenarios for mitigation planning and preparedness training, or to produce a probabilistic flood map. The RFMS can provide more accurate surge prediction with uncertainties if NHC can provide more accurate storm forecasts in the future. By incorporating storms for future climate and sea level rise, the RFMS could be used to generate future flood maps for coastal resilience and adaptation planning.

Showing Up after the Storm: Our "Fickle" Bleeding Heart?

While usually lauded, "empathic giving" may actually lead to suboptimal outcomes due in part to the enhancement of tribal sentiments in individual interactions, as well as by decisions driven more by emotional, rather than rational, considerations in the giving process. This point is linked to recent suggestions that government should reform social safety nets in order to decrease these negative interactions, and increase their efficacy. To this end, we use analyses of the September Supplements to the Current Population Survey in order to explore and find a negative change in individual-level volunteering subsequent to hurricanes Katrina and Ike, but not after hurricane Charley. We also find variations by region, and in particular, in "Deep Blue" states, as well as by whether individuals were located in the hurricane-affected states. Our findings are consistent with the notion that empathy may lead to more problems, including burnout and stratified giving, with implications for a public or private call to action.

A Novel Financial Market for Mitigating Hurricane Risk. Part I: Market Structure and Model Results

A novel financial market for hedging the effects of landfalling hurricanes is described and illustrated. The structure of the market is one sided and parimutuel, so that participants buy contracts pertaining to hurricane landfall locations from an exchange rather than from other market participants, and settlements for contracts associated with the landfall location are funded by purchases in all other outcomes. Contract prices are updated automatically and objectively using a recently developed adaptive control algorithm that responds to inferred aggregate probability assessments of the market participants. The market is intended to supplement insurance by providing a mechanism to shift risk for costs not covered under existing windstorm insurance. Operation of the market mechanism is illustrated in an idealized setting and in a spatially explicit historical simulation for Hurricane Charley (2004). A companion paper in this issue describes empirical validation of this market mechanism in an experimental market setting.

The Gradient Velocity Track Display (GrVTD) Technique for Retrieving Tropical Cyclone Primary Circulation from Aliased Velocities Measured by Single-Doppler Radar

The ground-based velocity track display (GBVTD) technique was developed to estimate the primary circulations of landfalling tropical cyclones (TCs) from single-Doppler radar data. However, GBVTD cannot process aliased Doppler velocities, which are often encountered in intense TCs. This study presents a new gradient velocity track display (GrVTD) algorithm that is essentially immune to the Doppler velocity aliasing. GrVTD applies the concept of gradient velocity–azimuth display (GVAD) to the GBVTD method. A GrVTD-simplex algorithm is also developed to accompany GrVTD as a self-sufficient algorithm suite. The results from idealized experiments demonstrate that the circulation center and winds retrieved from GrVTD with aliased velocity and GBVTD with dealiased velocity are in good agreement, but GrVTD is more sensitive to random observation errors. GrVTD was applied to Hurricane Charley (2004) where the majority of the Doppler velocities of the inner-core region were aliased. The GrVTD-retrieved circulation pattern and magnitude are nearly identical to those retrieved in GBVTD with manually dealiased velocities. Overall, the performance of GrVTD is comparable but is more sensitive to the data distribution than that of the original GBVTD using dealiased velocity. GrVTD can be used as a preprocessor for dealiasing velocity in TCs before the data are used in GBVTD or other algorithms.