The geomorphic significance of hurricanes on coral-fringed calcium carbonate coastlines: Hurricane Wilma 15-25 October 2005, northeastern Yucatan Peninsula, Mexico

<p>Hurricanes and tropical storms can cause large scale morphological changes to barrier beach systems in tropical environments. Many such systems are fronted by coral reefs; however, unlike siliciclastic barrier beaches, little is known about the significance of hurricanes to barrier beach evolution on coral-fringed calcium carbonate coastlines. This study provides a detailed assessment of the impacts of Hurricane Wilma, a major hurricane, on the reef-protected and exposed barrier beaches of northeastern Yucatan Peninsula, Mexico. The study considers both the short (0-8 months) and medium term (8-56 months) response, and postulates the significance of major storm events over the longer term. Hurricane Wilma made landfall in late October 2005 as a Category 4 hurricane, bringing sustained wind speeds of 67 ms-1, and storm waves with significant wave heights (HS) ≈ 13 m. The storm persisted for over 20 hours, while storm waves inundated the low lying barrier beaches and rainfall flooded inland wetlands and lagoons. To determine the impacts of Hurricane Wilma and quantify post-storm recovery of reef-protected and unprotected barrier beaches, geomorphic mapping and post-storm surveying (2006 and 2010) was completed at 49 locations between Punta Nizuc and Punta Maroma. In addition, 220 sediment samples were collected from across barrier beaches and the backreef lagoon for textural and petrographic analysis. Satellite imagery was also used to quantify immediate storm impacts and recovery of the shoreline. Barrier beaches were found to have responded to storm waves in two broadly different ways: reef-protected beaches accreted by between 2.1 and 24.6 m, as the beach and foredunes were reworked. In contrast, unprotected beaches underwent erosion of over 10 m. By 2006, reef-protected beaches had undergone rapid shoreface and beachface adjustment. Over the next four years, these beaches gradually transgressed landwards and aggraded subaerially as they readjusted to their pre-storm equilibrium beach profile. Exposed beaches responded much more rapidly than those protected by reefs, with shoreline adjustment occurring within eight months of the storm. Subaerial beach development was, however, much slower, requiring extended calm conditions to infill the eroded beach. The storm and post storm geomorphic responses were found to be highly variable alongshore, and influenced by several factors, including dune height, beach width, and wave exposure. The results indicate that under the contemporary climatic conditions hurricanes are key drivers of barrier beach evolution over the short (0-8 months) to medium terms (8-56 months), but are not so influential over longer time scales. However, an expected increase in the number of major storms (category 3-5) in the future may increase the significance of hurricanes to longer term barrier evolution, with the storm impacts likely to be greater and the recovery times longer. Understanding these responses is particularly critical as many areas continue to be developed, and as the coral reef protecting the coastline becomes threatened by the implications of climatic change.</p>

The geomorphic significance of hurricanes on coral-fringed calcium carbonate coastlines: Hurricane Wilma 15-25 October 2005, northeastern Yucatan Peninsula, Mexico

<p>Hurricanes and tropical storms can cause large scale morphological changes to barrier beach systems in tropical environments. Many such systems are fronted by coral reefs; however, unlike siliciclastic barrier beaches, little is known about the significance of hurricanes to barrier beach evolution on coral-fringed calcium carbonate coastlines. This study provides a detailed assessment of the impacts of Hurricane Wilma, a major hurricane, on the reef-protected and exposed barrier beaches of northeastern Yucatan Peninsula, Mexico. The study considers both the short (0-8 months) and medium term (8-56 months) response, and postulates the significance of major storm events over the longer term. Hurricane Wilma made landfall in late October 2005 as a Category 4 hurricane, bringing sustained wind speeds of 67 ms-1, and storm waves with significant wave heights (HS) ≈ 13 m. The storm persisted for over 20 hours, while storm waves inundated the low lying barrier beaches and rainfall flooded inland wetlands and lagoons. To determine the impacts of Hurricane Wilma and quantify post-storm recovery of reef-protected and unprotected barrier beaches, geomorphic mapping and post-storm surveying (2006 and 2010) was completed at 49 locations between Punta Nizuc and Punta Maroma. In addition, 220 sediment samples were collected from across barrier beaches and the backreef lagoon for textural and petrographic analysis. Satellite imagery was also used to quantify immediate storm impacts and recovery of the shoreline. Barrier beaches were found to have responded to storm waves in two broadly different ways: reef-protected beaches accreted by between 2.1 and 24.6 m, as the beach and foredunes were reworked. In contrast, unprotected beaches underwent erosion of over 10 m. By 2006, reef-protected beaches had undergone rapid shoreface and beachface adjustment. Over the next four years, these beaches gradually transgressed landwards and aggraded subaerially as they readjusted to their pre-storm equilibrium beach profile. Exposed beaches responded much more rapidly than those protected by reefs, with shoreline adjustment occurring within eight months of the storm. Subaerial beach development was, however, much slower, requiring extended calm conditions to infill the eroded beach. The storm and post storm geomorphic responses were found to be highly variable alongshore, and influenced by several factors, including dune height, beach width, and wave exposure. The results indicate that under the contemporary climatic conditions hurricanes are key drivers of barrier beach evolution over the short (0-8 months) to medium terms (8-56 months), but are not so influential over longer time scales. However, an expected increase in the number of major storms (category 3-5) in the future may increase the significance of hurricanes to longer term barrier evolution, with the storm impacts likely to be greater and the recovery times longer. Understanding these responses is particularly critical as many areas continue to be developed, and as the coral reef protecting the coastline becomes threatened by the implications of climatic change.</p>

Nowcasting Wind, Wave, Current and Turbulence Intensity for Offshore Wind Power Operation and Maintenance

In order to improve offshore wind power operation and maintenance (O&M), particularly during tropical and non-tropical cyclones, short-term forecasts or nowcasts up to 6 hours of meteorological and oceanographic (met-ocean) parameters including wind, waves, currents and turbulence intensity are needed. On the basis of numerous air-sea and wind-wave interaction experiments, datasets are analyzed including those from simultaneous measurements of wind and waves during Hurricane Wilma. Formulas are presented for nowcasts of met-ocean parameters. For quality assurance, these proposed formulas are further verified by independent datasets as provided in the literature. This manual-like guide should be useful for offshore wind-power O&M technicians and operators.

Evaluation of the Surface Wind Field over Land in WRF Simulations of Hurricane Wilma (2005). Part I: Model Initialization and Simulation Validation

While global and regional dynamical models are used to predict the tracks and intensities of hurricanes over the ocean, these models are not currently used to predict the wind field and other impacts over land. This two-part study performs detailed evaluations of the near-surface, over-land wind fields produced in simulations of Hurricane Wilma (2005) as it traveled across South Florida. This first part describes the production of two high-resolution simulations using the Weather Research and Forecasting Model (WRF), using different boundary layer parameterizations available in WRF: the Mellor-Yamada-Janjić (MYJ) scheme and the Yonsei University (YSU) scheme. Initial conditions from the Global Forecasting System (GFS) are manipulated with a vortex bogussing technique to modify the initial intensity, size, and location of the cyclone. It is found possible through trial and error to successfully produce simulations using both the YSU and MYJ schemes that closely reproduce the track, intensity, and size of Wilma at landfall. For both schemes the storm size and structure also show good agreement with the wind fields diagnosed by H*WIND and the Tropical Cyclone Surface Wind Analysis (TCSWA). Both over water and over land, the YSU scheme has stronger winds over larger areas than MYJ, but the surface winds are more reduced in areas of greater surface roughness, particularly in urban areas. Both schemes produced very similar inflow angles over land and water. The over-land wind fields are examined in more detail in the second part of this study.

Evaluation of the Surface Wind Field over Land in WRF Simulations of Hurricane Wilma (2005). Part II: Surface Winds, Inflow Angles, and Boundary Layer Profiles

This is the second of a two-part study that explores the capabilities of a mesoscale atmospheric model to reproduce the near-surface wind fields in hurricanes over land. The Weather Research and Forecasting Model (WRF) is used with two planetary boundary layer parameterizations: the Yonsei University (YSU) and the Mellor-Yamada-Janjić (MYJ) schemes. The first part presented the modeling framework and initial conditions used to produce simulations of Hurricane Wilma (2005) that closely reproduced the track, intensity, and size of its wind field as it passed over South Florida. This part explores how well these simulations can reproduce the winds at fixed points over land by making comparisons to observations from airports and research weather stations. The results show that peak wind speeds are remarkably well reproduced at several locations. Wind directions are evaluated in terms of the inflow angle relative to the storm center, and the simulated inflow angles are generally smaller than observed. Localized peak wind events are associated with vertical vorticity maxima in the boundary layer with horizontal scales of 5-10 km. The boundary layer winds are compared to wind profiles obtained by velocity-azimuth display (VAD) analyses from National Weather Service Doppler radars at Miami and Key West; results from these comparisons are mixed. Nonetheless the comparisons to surface observations suggest that when short-term hurricane forecasts can sufficiently predict storm track, intensity, and size, they will also be able to provide useful information on extreme winds at locations of interest.

INFLUENCE OF REGULARITY OF SATELLITE MICROWAVE RADIOMETER MEASUREMENTS ON THE ACCURACY OF BRIGHTNESS TEMPERATURE REPRODUCTION IN AREAS OF THE TROPICAL CYCLONES

An accuracy of reproduction of daily variations in the ocean–atmosphere system brightness temperature in the areas of development and movement of tropical hurricanes in the Caribbean Sea and Gulf of Mexico is analyzed. The analysis is based on the data of single and group satellite microwave radiometer measurements. The results are obtained using archival measurement data of SSM/I radiometers from the F11, F13, F14, and F15 DMSP satellites during the period of existence of tropical hurricanes Bret and Wilma. An example is given to demonstrate the use of daily brightness temperatures obtained from DMSP satellites for monitoring the development and propagation of hurricane Wilma.

Tracing Extreme Updrafts in Hurricane Wilma (2005) to Their Boundary Layer Roots Using Trajectories: A Thermodynamic and Structural Analysis

This study uses a recently developed trajectory model to trace eyewall updrafts in a high-resolution Hurricane Wilma (2005) prediction to their roots in the maritime boundary layer (MBL) in order to better understand their thermodynamics and how they interact with the swirling winds. Out of 97 020 four-hour backward trajectories seeded from the upper troposphere, the 45% of them originating from the MBL are stratified into five subsamples binned by peak vertical velocity wMAX. Of particular interest are the thermodynamic characteristics of parcels belonging to the wMAX-Extreme subsample (i.e., those with wMAX exceeding 20 m s−1) that ascend through Wilma’s strongest convective burst (CB) cores. A vertical momentum budget computed along a selected wMAX-Extreme trajectory confirms that the parcel possesses large positive buoyancy that more than compensates for negative hydrometeor loading to yield an upper-tropospheric wMAX ~ 30 m s−1. Comparing all 1170 wMAX-Extreme trajectories with all 19 296 secondary circulation trajectories shows that the former tends to originate from the MBL where equivalent potential temperature θe and ocean surface heat and moisture fluxes are locally enhanced. The wMAX-Extreme parcels become further differentiated from the background ascent in terms of their (i) greater updraft width and smaller θe reduction while ascending into the midtroposphere, implying lower environmental entrainment rates, and (ii) less hydrometeor loading in the z = 3–5-km layer. The Lagrangian analysis herein bridges two previous studies that focused separately on the importance of high SSTs and fusion latent heat release to the development of CBs, the latter of which may facilitate upper-level warm core development through their compensating subsidence.

Hurricane Preparedness and Response Along Florida's Central-East Coast: Indian River Mosquito Control District's Experiences Over the Years

ABSTRACT The hurricane is no stranger to longtime residents of Florida's east coast. In 1979, after about 15 years of local inactivity, Hurricane David made landfall in West Palm Beach. Thirteen years later and 100 miles south, category 5 Hurricane Andrew caused catastrophic damage when it hit the city of Homestead in the Miami-Dade area. In 2004, the counties along the east coast of central Florida were hit by 2 devastating hurricanes, Frances and Jeanne, that made landfall at Sewall's Point just 20 days apart. The very next year, Hurricane Wilma made landfall near Everglades City as a Category 3 storm. After a decade of relief, a glancing blow from Hurricane Matthew struck in 2016, only to be followed by the extremely devastating Hurricane Irma just 1 year later. Each of these hurricanes caused significant property damage and mosquito problems for the Florida residents affected by these storms. In 1997, the Indian River Mosquito Control District (IRMCD) developed a hurricane preparedness plan outlining the appropriate action to be taken depending on the severity of the approaching storm. The IRMCD has also learned to negotiate the intricacies of the Federal Emergency Management Agency's reimbursement program, thus reducing the financial impact to the District. This paper provides an overview of how IRMCD has prepared, reacted, and followed-up with the seemingly constant parade of hurricanes that have threatened and affected the east coast over time.