Y. Peter Sheng

Relative influence of various water quality parameters on light attenuation in Indian River Lagoon

Abstract Six synoptic sampling events were conducted in the Indian River Lagoon (IRL) between April and June, 1997 to collect TSS (total suspended solids), color (dissolved organic matter), chl a (chlorophyll a ), and light (photosynthetically active radiation (PAR)) data. These data were used to develop our understanding of light attenuation dynamics in the IRL and for verification of a numerical light model. Data from our study show that tripton (non-algal particulate matter calculated from TSS and chl a corrected for pheophytin) has a dominant effect on light attenuation in the IRL. For each synoptic event, there exists a positive correlation between the event-averaged downwelling light attenuation coefficient, K d (PAR), and event-averaged tripton concentration. A negative correlation is found between the event-averaged K d (PAR) and the event-averaged color, while a positive correlation is found between event-averaged K d (PAR) and event-averaged chl a concentration. The correlation between event-averaged tripton and event-averaged K d (PAR) is the only one of the three to show significance at the 0.05 level. Relative contributions of color, chl a , and tripton to light attenuation were found to be 5–25%, 10–26%, and 59–78% of K d (PAR), respectively. These values depend on the method for partitioning K d (PAR) and the method for obtaining average value of relative partitioned K d (PAR) from all the data points. These values show that tripton has a more dominant influence on light attenuation in the IRL than in Tampa Bay and Charlotte Harbor, but comparable to that in Florida Bay. The effect of suspended chlorophyll on light attenuation in the IRL is less than that in Tampa Bay, comparable to Charlotte Harbor, but more than that in Florida Bay. A numerical process-based light attenuation model has been developed to calculate K d (PAR) based on measured or simulated values of TSS, color, and chl a . The model was found to give reasonable estimates of K d (PAR) throughout the IRL.

Evaluation of coastal inundation hazard for present and future climates

Coastal inundation from hurricane storm surges causes catastrophic damage to lives and property, as evidenced by recent hurricanes including Katrina and Wilma in 2005 and Ike in 2008. Changes in hurricane activity and sea level due to a warming climate, together with growing coastal population, are expected to increase the potential for loss of property and lives. Current inundation hazard maps: Base Flood Elevation maps and Maximum of Maximums are computationally expensive to create in order to fully represent the hurricane climatology, and do not account for climate change. This paper evaluates the coastal inundation hazard in Southwest Florida for present and future climates, using a high resolution storm surge modeling system, CH3D-SSMS, and an optimal storm ensemble with multivariate interpolation, while accounting for climate change. Storm surges associated with the optimal storms are simulated with CH3D-SSMS and the results are used to obtain the response to any storm via interpolation, allowing accurate representation of the hurricane climatology and efficient generation of hazard maps. Incorporating the impact of anticipated climate change on hurricane and sea level, the inundation maps for future climate scenarios are made and affected people and property estimated. The future climate scenarios produce little change to coastal inundation, due likely to the reduction in hurricane frequency, except when extreme sea level rise is included. Calculated coastal inundation due to sea level rise without using a coastal surge model is also determined and shown to significantly overestimate the inundation due to neglect of land dissipation.

Architecture of a Community Infrastructure for Predicting and Analyzing Coastal Inundation

The Southeastern Universities Research Association (SURA) has advanced the SURA Coastal Ocean Observing and Prediction (SCOOP) program as a multi-institution collaboration to design and prototype a modular, distributed system for real-time prediction and visualization of the coastal impacts from extreme atmospheric events, including hurricane inundation and waves. The SCOOP program vision is a community “cyberinfrastructure” that enables advances in the science of environmental prediction and coastal hazard planning. The system architecture is a coordinated and distributed network of interoperable, modularized components that include numerical models, information catalogs, distributed archives, computing resources, and network infrastructure. The components are linked over the Internet by standardized web-service interfaces in a service-oriented architecture (SOA). The design philosophy allows geographically disparate partnering institutions to provide complementary data-provider and integration services. The overall system enables coordinated sharing of resources, tools, and ideas among a virtual community of coastal and computer scientists. The distributed design builds on the notion that standards enable innovation, and seeks to leverage successes of the World Wide Web by creating an environment that nurtures interaction between the research community, the private sector, and government agencies working together on behalf of the nation.

Three-Dimensional Modeling of Storm Surge and Inundation Including the Effects of Coastal Vegetation

Two-dimensional (2D) and three-dimensional (3D) hydrodynamic models are used to simulate the hurricane-induced storm surge and coastal inundation in regions with vegetation. Typically, 2D storm surge models use an enhanced Manning coefficient while 3D storm surge models use a roughness height to represent the effects of coastal vegetation on flow. This paper presents a 3D storm surge model which accurately resolves the effects of vegetation on the flow and turbulence. First, a vegetation-resolving 1DV Turbulent Kinetic Energy model (TKEM) is introduced and validated with laboratory data. This model is both robust enough to accurately model flows in complex canopies, while compact and efficient enough for incorporation into a 3D storm surge-wave modeling system: Curvilinear Hydrodynamics in 3D-Surface WAves Nearshore (CH3D-SWAN). Using the 3D vegetation-resolving model, three numerical experiments are conducted. In the first experiment, comparisons are made between the 2D Manning coefficient approach and the 3D vegetation-resolving approach for simple wind-driven flow. In a second experiment, 2D and 3D representations of vegetation produce similar inundations from the same hurricane forcing, but differences in momentum are found. In a final experiment, varying inundation between seemingly analogous 2D and 3D representations of vegetation are demonstrated, pointing to a significant scientific need for data within wetlands during storm surge events. This study shows that the complex flow structures within vegetation canopies can be accurately simulated using a vegetation-resolving 3D storm surge model, which can be used to assess the feasibility for future wetland restoration projects.

Circulation and Flushing in the Lagoonal System of the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR), Florida

Abstract Circulation and flushing inside the lagoon system of Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR or GTM) have been studied using a three-dimensional numerical circulation model CH3D. The lagoon system includes two tidal inlets (St. Augustine Inlet and Matanzas Inlet). To ensure accuracy in model results, we extend the model domain to include a large portion of the coastal water and the Ponce de Leon Inlet in the south. Water levels on the open boundaries are provided by the East Coast (2001) ADCIRC Tidal Database. Model simulations of barotropic and baroclinic circulation from April 1 to May 31, 2004, produced reasonable water levels at numerous stations inside the GTM. Simulated salinity results are not as good because of the lack of freshwater inflow data inside the GTM and salinity data offshore. Using the simulated flow fields, we solve the three-dimensional transport equations for conservative species, and determine the flushing characteristics inside the GTM in terms of the 50% renewal time of the conservative species within each of eight segments, which are selected by considering the geographical features and proximity to tidal inlets and rivers. The flushing results indicate that tide is the most dominant flushing mechanism, while river and salinity are important flushing mechanisms for segments that are far from the tidal inlets. The normalized flushing times, defined as the 50% renewal time divided by the volume of the segment, are calculated for the eight segments and compared with each other. Comparing the “normalized” flushing time at all segments, a relative flushing ranking (RFR) is generated that ranks the “normalized” flushing time from the shortest to the longest as follows: segment 2 (includes St. Sebastian), segment 8 (near Ponce Inlet), segment 3 (includes Fort Matanzas), segment 7 (near Ponce Inlet), segment 1 (includes Pine Island), segment 4 (includes Pellicer Creek), segment 6 (includes High Bridge Road), and segment 5 (includes Bings Landing). This quantitative ranking of flushing characteristics inside the GTM is made possible because of the use of a three-dimensional numerical circulation and transport model that incorporates the effect of hydrodynamics on flushing. These results provide much more quantitative information than the simple empirical residence time indices (1–4) developed for the GTM in a previous study. CH3D was also applied to simulate the circulation during January 25 to February 3, 2006. Simulated currents inside the St. Augustine Inlet on February 2, 2006, compare favorably with the currents measured by Acoustic Doppler Current Profiler (ADCP). Model simulated flow rates through St. Augustine and Matanzas inlets reproduced measured data on July 1 and June 16, 2004, respectively. Model-simulated currents and water levels improved when the flooding-and-drying version of the model was used. The three-dimensional modeling approach can be used to provide sguidance on resource management and the development of sampling strategies for several ongoing and prospective biogeochemical studies in the GTM.

Toward the Probabilistic Simulation of Storm Surge and Inundation in a Limited-Resource Environment

Abstract To create more useful storm surge and inundation forecast products, probabilistic elements are being incorporated. To achieve the highest levels of confidence in these products, it is essential that as many simulations as possible are performed during the limited amount of time available. This paper develops a framework by which probabilistic storm surge and inundation forecasts within the Curvilinear Hydrodynamics in 3D (CH3D) Storm Surge Modeling System and the Southeastern Universities Research Association Coastal Ocean Observing and Prediction Program’s forecasting systems are initiated with specific focus on the application of these methods in a limited-resource environment. Ensemble sets are created by dividing probability density functions (PDFs) of the National Hurricane Center model forecast error into bins, which are then grouped into priority levels (PLs) such that each subsequent level relies on results computed earlier and has an increasing confidence associated with it. The PDFs are...

A Real-Time Forecasting System for Hurricane Induced Storm Surge and Coastal Flooding

Hurricanes cause property damages and loss of lives in the U.S. every year. In 2004, four major hurricanes caused more than 5 billion dollars in damage each in Florida alone. Katrina in 2005 caused more than

Simulating complex storm surge dynamics: Three‐dimensionality, vegetation effect, and onshore sediment transport

200 billion dollars in damage. Major damage caused by a hurricane is usually associated with storm surge and coastal flooding. This paper presents CH3D-SSMS, a robust storm surge and coastal flooding forecasting system for tropical and extratropical storms. The basic forecasting system couples a storm surge and coastal flooding model (CH3D) with a shallow water wave model (SWAN) in a high resolution (50–500m) coastal/estuary/inland model grid. The coupled surge-wave model receives open boundary conditions of surge and wave from a global surge model (ADCIRC) and a global wave model (WAVEWATCH-III) which cover the Gulf of Mexico and Western Atlantic. Currently high resolution grids have been set up for the East Florida Coast (including St. Johns River, Indian River Lagoon, and adjacent coastal water), Tampa Bay and Charlotte Harbor, Florida Panhandle, and Chesapeake Bay and adjacent coastal waters. The forecast wind and atmospheric pressure information are provided by a number of NOAA wind models including NAM (North Atlantic Mesoscale), GFDL-Hurricane model, and an analytic model which uses GFDL hurricane parameters. Based on the forecast wind, the CH3D-SSMS produces an 84-hour forecast of water level, wave height/period/direction, flow field, and maximum of maximum (MOM) water level and inundation, every 6 hours. Prior to forecasting, the model performs a 24-hour nowcast using analysis wind. Performance of the CH3D-SSMS forecasting system has been demonstrated using results from 2003 (Isabel) and 2004 (Frances and Ivan) hurricanes. Forecasting of the impact of Hurricane Wilma on the Charlotte Harbor region is illustrated to reflect the current capabilities and weaknesses of the CH3D-SSMS as well as hurricane wind model. To improve the forecasting system, more accurate and efficient hurricane wind models and coupling of models of various processes and scales are needed. Hurricane-ground interaction should be incorporated into the hurricane wind model to produce more realistic near ground wind after hurricane landfall. Cyberinfrastructure should also be employed to facilitate regional and community collaboration.

Toward High-Resolution, Rapid, Probabilistic Forecasting of the Inundation Threat from Landfalling Hurricanes

The 3D hydrodynamics of storm surge events, including the effects of vegetation and impact on onshore transport of marine sediment, have important consequences for coastal communities. Here, complex storm surge dynamics during Hurricane Ike are investigated using a three-dimensional (3D), vegetation-resolving storm surge-wave model (CH3D-SWAN) which includes such effects of vegetation as profile drag, skin friction, and production, dissipation, and transport of turbulence. This vegetation-resolving 3D model features a turbulent kinetic energy (TKE) closure model, which uses momentum equations with vegetation induced profile and skin friction drags, a dynamic q2 equation including turbulence production and dissipation by vegetation, as well as vegetation-dependent algebraic length scale equations, and a Smagorinsky type horizontal turbulence model. This vegetation model has been verified using extensive laboratory tests, but this study is a comparison of 2D and 3D simulations of complex storm surge dynamics during Hurricane Ike. We examine the value of 3D storm surge models relative to 2D models for simulating coastal currents, effects of vegetation on surge, and sediment transport during storm events. Comparisons are made between results obtained using simple 2D formulations for bottom friction, the Manning coefficient (MC) approach, and physics-based 3D vegetation-modeling (VM) approach. Lastly, the role that the 3D hydrodynamics on onshore transport and deposition of marine sediments during the storm is investigated. While both the 3D and 2D results simulated the water level dynamics, results of the physics-based 3D VM approach, as compared to the 2D MC approach, more accurately captures the complex storm surge dynamics. This article is protected by copyright. All rights reserved.

A Regional Testbed for Storm Surge and Coastal Inundation Models - An Overview

AbstractState-of-the-art coupled hydrodynamic and wave models can predict the inundation threat from an approaching hurricane with high resolution and accuracy. However, these models are not highly efficient and often cannot be run sufficiently fast to provide results 2 h prior to advisory issuance within a 6-h forecast cycle. Therefore, to produce a timely inundation forecast, coarser grid models, without wave setup contributions, are typically used, which sacrifices resolution and physics. This paper introduces an efficient forecast method by applying a multidimensional interpolation technique to a predefined optimal storm database to generate the surge response for any storm based on its landfall characteristics. This technique, which provides a “digital lookup table” to predict the inundation throughout the region, is applied to the southwest Florida coast for Hurricanes Charley (2004) and Wilma (2005) and compares well with deterministic results but is obtained in a fraction of the time. Because of t...