RAPID RESPONSE MEASUREMENTS OF HURRICANE WAVES AND STORM SURGE
By
URIAH MICHAEL GRAVOIS
A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE
UNIVERSITY OF FLORIDA
2010 °c 2010 Uriah Michael Gravois
2 I dedicate this to my family
3 ACKNOWLEDGMENTS I express my sincere gratitude to my advisors, Andrew Kennedy, Alexandru Sheremet and Robert Dean, for the priceless knowledge they have passed on to me during my time at the University of Florida. I also express sincere appriciation to everyone who has contributed to the success of this study. The following sentences attempt to recognize many of these contributions. Most of the preparation and fieldwork was completed by the University of Florida Coastal and Oceanographic Engineering Laboratory (COEL) staff including Vicktor Adams, Sidney Schofield, Jimmy Joiner, Danny Brown and Richard Booze. Extensive training and oversight of the studies’
fieldwork was provided by Cheryl Thacker, the Dive Saftey Officer for the The University of Florida Diving Science and Saftey Program (DSSP). Special recognitions go to the dive team including, Vicktor Adams, Andrew Kennedy, and Justin Marin. The United States Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center completed gauge retrievals for Tropical Storm Fay. The University of North Carolina at Chapel Hill Institute of Marine Sciences completed gauge deployment and retrieval for Hurricane Hanna. The Louisiana University Marina Consortium (LUMCON) and The Texas University Marine Consortium provided captains and boats for Hurricane Gustav and Hurricane Ike gauge retrievals respectively. The following helicopter companies were hired for pioloting gauge deployments; Helicopter Adventures (Tropical Storm Ernesto), Ocean Helicopters (Hurricane Noel, Tropical Storm Fay, and
Hurricane Gustav), Roni Avisar (Hurricane Hanna) and Austin Helijet (Hurricane Ike). I would also like to recognize my office mates during this study, Sergio Jaramillio, Ilgar Safik, with special thanks going out to Bryan Zachary as a visiting scholar. Further acknowlegements go out to other hurricane response teams for their help planning deployments including; The Florida Costal Monitoring Program wind tower team, The Texas Tech ”stick net” wind team and the USGS surge team. Also thanks go out to the past and future users of this study’s gauges including; Spencer Rodgers with
4 North Carolina Sea Grant, USGS surge teams, Jim Chen’s group at Louisiana State University, Brett Webb at The University of South Alabama and Rick Leutich’s group at The Univeristy of North Carolina at Chapel Hill. Finally, enormous thanks goes out to the study’s funding agency Florida Sea Grant under R/C-S-46.
5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...... 4
LIST OF TABLES ...... 8
LIST OF FIGURES ...... 9
ABSTRACT ...... 11
CHAPTER 1 INTRODUCTION AND METHODOLOGY ...... 13 1.1 Rapid Response Motivation ...... 13 1.2 Custom Wave and Surge Gauges ...... 13 1.2.1 Application Specific Requirements ...... 13 1.2.2 Basic Concepts ...... 14 1.2.3 Design Details ...... 15 1.2.4 Calibration and Resolution ...... 17 1.2.5 Gauge Housing and Anchoring Base ...... 18 1.3 Field Campaign ...... 20 1.3.1 Helicopter Company Relations and Safety ...... 20 1.3.2 Deployment ...... 21 1.3.3 Retrieval ...... 22 2 BACKGROUND AND GENERAL THEORY ...... 25 2.1 Overview of Hurricanes ...... 25 2.1.1 Climatology and Risk ...... 25 2.1.2 Wind and Pressure Characteristics ...... 26 2.2 The National Oceanic and Atmospheric Administration ...... 28 2.3 Waves ...... 29 2.3.1 Generation ...... 29 2.3.2 Linear Equations ...... 30 2.3.3 National Data Buoy Center ...... 31 2.4 Tides ...... 32 2.4.1 Harmonic Analysis of Tides ...... 32 2.4.2 Astronomical vs Storm Tide ...... 33 2.4.3 National Ocean Service ...... 33 2.4.4 United States Geological Survey ...... 34
3 DATA ANALYSIS TECHNIQUES ...... 35
3.1 Surge Processing ...... 35 3.2 Wave Data Processing ...... 35 3.3 Liability Statement and Data Access ...... 37
6 APPENDIX A ERNESTO ...... 38
B NOEL ...... 44
C FAY ...... 50 D GUSTAV ...... 56
E HANNA ...... 66 F IKE ...... 72 REFERENCES ...... 79
BIOGRAPHICAL SKETCH ...... 80
7 LIST OF TABLES Table page 1-1 Calibration Coefficients ...... 24
2-1 SAFFIR-SIMPSON HURRICANE WIND SCALE ...... 27
A-1 Tropical Storm Ernesto deployment locations ...... 38
B-1 Hurricane Noel deployment locations ...... 44
C-1 Tropical Storm Fay deployment locations ...... 50 D-1 Hurricane Gustav deployment locations ...... 56 E-1 Hurricane Hanna deployment locations ...... 66
F-1 Hurricane Ike deployment locations ...... 72
8 LIST OF FIGURES Figure page 1-1 Model 85 pressure sensor and TFX-11v2 data logger ...... 16
1-2 Custom PCB amplifier schematic design ...... 17
1-3 Example plot of study gauge cross-calibration with Paros Scientific pressure sensor ...... 19 1-4 Steel Anchor Base ...... 20
1-5 Helicopter deployment with detachable sled ...... 21 1-6 Helicopter deployment with folding leg base ...... 22 1-7 Scuba diver retrieval of pressure sensor ...... 23
2-1 HURISK category 3 hurricane 100 year return period map ...... 26
2-2 Satellite image of Hurricane Rita ...... 28 2-3 Wave forecasting chart developed by Bretschnieder ...... 30
2-4 Wave dispersion relation plot ...... 31 2-5 Map of National Data Buoy Center stations ...... 32 A-1 National Hurricane Center forecast tracks for Tropical Storm Ernesto ...... 39 A-2 Tropical Storm Ernesto track and Intensity ...... 40 A-3 Tropical Storm Ernesto deployment locations map ...... 41
A-4 Wave height measurements for Tropical Storm Ernesto ...... 42
A-5 Wave frequency measurements for Tropical Storm Ernesto ...... 43 B-1 National Hurricane Center forecast tracks for Hurricane Noel ...... 45 B-2 Hurricane Noel track and Intensity ...... 46
B-3 Hurricane Noel deployment locations map ...... 47 B-4 Wave height measurements for Hurricane Noel ...... 48
B-5 Wave frequency measurements for Hurricane Noel ...... 49 C-1 National Hurricane Center forecast tracks for Tropical Storm Fay ...... 51
C-2 Tropical Storm Fay track and Intensity ...... 52
C-3 Tropical Storm Fay deployment locations map ...... 53
9 C-4 Wave height measurements for Tropical Storm Fay ...... 54 C-5 Wave frequency measurements for Tropical Storm Fay ...... 55
D-1 National Hurricane Center forecast tracks for Hurricane Gustav ...... 57
D-2 Hurricane Gustav track and Intensity ...... 58 D-3 Hurricane Gustav deployment locations map 1 ...... 59
D-4 Hurricane Gustav deployment locations map 2 ...... 60 D-5 Hurricane Gustav deployment locations map 3 ...... 61 D-6 Wave height measurements for Hurricane Gustav 1 ...... 62
D-7 Wave frequency measurements for Hurricane Gustav 1 ...... 63 D-8 Wave height measurements for Hurricane Gustav 2 ...... 64
D-9 Wave frequency measurements for Hurricane Gustav 2 ...... 65
E-1 National Hurricane Center forecast tracks for Hurricane Hanna ...... 67 E-2 Hurricane Hanna track and Intensity ...... 68
E-3 Hurricane Hanna deployment locations map ...... 69 E-4 Wave height measurements for Hurricane Hanna ...... 70 E-5 Wave frequency measurements for Hurricane Hanna ...... 71 F-1 National Hurricane Center forecast tracks for Hurricane Ike ...... 73 F-2 Hurricane Ike track and intensity ...... 74
F-3 Hurricane Ike deployment locations map 1 ...... 75 F-4 Hurricane Ike deployment locations map 2 ...... 76
F-5 Wave height measurements for Hurricane Ike ...... 77 F-6 Wave frequency measurements for Hurricane Ike ...... 78
10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science RAPID RESPONSE MEASUREMENTS OF HURRICANE WAVES AND STORM SURGE By Uriah Michael Gravois August 2010 Chair: Alexandru Sheremet Major: Coastal and Oceanographic Engineering
Andrew (1992), Katrina (2005), and Ike (2008) are recent examples of extensive damage that resulted from direct hurricane landfall. Some of the worst damages from these hurricanes are caused by wind driven waves and storm surge flooding. The potential for more hurricane disasters like these continues to increase as a result of population growth and real estate development in low elevation coastal regions. Observational measurements of hurricane waves and storm surge play an important role in future mitigation efforts, yet permanent wave buoy moorings and tide stations are more sparse than desired. This research has developed a rapid response method using helicopters to install temporary wave and surge gauges ahead of hurricane landfall. These temporary installations, with target depths from 10-15 m and 1-7 km offshore depending on the local shelf slope, increase the density of measurement points where the worst conditions are expected. The method has progressed to an operational state and has successfully responded to storms Ernesto (2006), Noel (2007), Fay (2008), Gustav (2008), Hanna (2008) and Ike (2008). The temporary gauges are pressure data loggers that measure at 1 Hz continuously for 12 days and are post-processed to extract surge and wave information. For the six storms studied, 45 out of 49 sensors were recovered by boat led scuba diver search teams, with 43 providing useful data for an 88 percent success rate. As part of the 20 sensor Hurricane Gustav response, sensors were also deployed in lakes and bays in
11 Louisiana, east of the Mississippi river delta. Gustav was the largest deployment to date. Generally efforts were scaled back for storms that were not anticipated to be highly destructive. For example, the cumulative total of sensors deployed for Ernesto, Noel,
Fay and Hanna was only 20. Measurement locations for Gustav spanned over 800 km of exposed coastline from Louisiana to Florida with sensors in close proximity to landfall near Cocodrie, Louisiana. Surge measurements between landfall and the Mississippi delta show 1.5 - 2 m of surge and values exceeding 2 m further from landfall north of the Mississippi delta. These observations demonstrate the importance of coastal geography on storm surge vulnerability. Waves measurements from Gustav show large waves of 5 m at all exposed locations from landfall to western Florida. Some smaller values were also recorded, likely to be due to depth limited breaking or sheltering from the
Mississippi delta. Two weeks after Hurricane Gustav, major Hurricane Ike entered the Gulf of Mexico threatening Texas. Unfortunately the sensors already deployed for Gustav reached the 12 day memory limit and did not catch the most extreme conditions of Ike. However, 9 additional sensors were deployed for Ike spanning 360 km of the Texas coast. These measurements show surge east of the Galveston, Texas landfall exceeding 4.5 m and wave heights greater than 5 m. Hurricane Ike was by far the most destructive of the 6 storms measured and has spawned separate work relating the extent of building damage to these measurements.
12 CHAPTER 1 INTRODUCTION AND METHODOLOGY
1.1 Rapid Response Motivation
In the absence of a hurricane or other violent storm, the waves and tides along the coast exhibit gradual spatial variation relative to the existing observational network of wave buoys and tide stations. These typical oceanic conditions are fairly well understood and can be predicted with reasonable accuracy through empirical relationships that are largely based on past and present observational wave and tide data. On the contrary, hurricane generated waves and tides vary substantially over small distances and over short timescales. These complexities are not fully resolved by the existing spacial density of permanent observation stations rendering them much more difficult to predict. The need for more systematic data collections during these extreme events has been recognized for many years (Harris, 1963), however, the infrequent nature of hurricane occurrences for a specific location has deterred most efforts. A solution was developed to create mobile monitoring networks at desired locations immediately before a critical event. Operational programs of this kind are in place to measure wind (Masters et al., 2010; Skwira et al., 2005) and surge (East et al., 2008), but none exist for wave measurements or offshore surge. This study was developed to fill this void through rapid response helicopter deployment of temporary observation stations, thus increasing the density of wave and tide measurements required to characterized a hurricane event.
1.2 Custom Wave and Surge Gauges
1.2.1 Application Specific Requirements
The decision was made in the proposal stages of this study to use sub-surface pressure sensors as the rapidly deployed gauge. Applying pressure sensors to measure waves and water levels is known to be a robust technique, which is a major requirement for this study. Other researchers have investigated the accuracy of sub-surface pressure sensors to measure surface waves (Bergan et al., 1968; Bishop & Donelan, 1987) with
13 co-located comparisons to surface buoys. The results agree that sub-surface pressure measurements of waves have an inherent error underestimating wave heights of less than 10 % and no errors for tide level measurements. These small errors are acceptable for this study given other advantages of applying sub-surface pressure sensors instead of surface buoys for hurricane response. The study’s finished pressure gauges and anchoring base together weigh only 50 pounds, however, proved to be immobile. In hurricane conditions, the tethering weight required to anchor surface buoys is an order of magnitude greater than sub-surface pressure sensors, yet they are still vulnerable to mobilization. As an example, National Data Buoy Center station 42035 was relocated 25 nautical miles by Hurricane Ike and on numerous other occasions surface buoys have gone adrift due to strong winds and large waves (Wang & Oey, 2008; Fan et al.,
2009; White & Buckingham, 1999). Other instances have been observed where measurements from surface buoys shut off or became unreliable in peak storm conditions. In comparison, this study’s response gauges deployed for Hurricane Ike and other storms, were immobile and collected continuous data throughout the storm. An optimum weight of the study’s sub-surface pressure sensor wave and tide gauges is heavy enough to be immobile but light enough for multiple units to be transported by helicopter and rapidly set up prior to a storm. In a fully operational state, this study requires 50-100 gauges to be available for response to several consecutive storms over a short time span. The study’s limited budget and the large number of gauges desired led to the design and fabrication of gauges in house. This resulted in an inexpensive cost per gauge, including parts and labor, of approximately 500 dollars.
1.2.2 Basic Concepts
For motionless water conditions there is a direct linear dependence between pressure and depth known as the hydrostatic principal. By this relationship the depth of
14 water η above the pressure sensors can be found from the equation
(Pabs − Patm) η = (1–1) ρg
where Pabs is the pressure timeseries measured by the gauges, Patm is the atmospheric or absolute sea level pressure, ρ is the depth averaged density of the water column above the measurement location and g is the acceleration of gravity. Note that the units Pa = N of pressure need to in Pascals ( m2 ). For the purposes of this study, density can be considered constant as it varies at most 3% in the most extreme ranges of temperature and salinity likely to be encountered. Therefore, water density can be estimated yielding very small uncertainty in the pressure-depth relationship. As a rule of thumb, 1 millibar (100 Pa) of air pressure is equivalent to 1 centimeter of water depth
100 Pa .01m = . (1–2) 1020 kg 9.81 m m3 s2
For non-hydrostatic conditions where the water is in motion and accelerating the mean pressure is equivalent to what would be the still water depth. This is commonly referred to as the mean water level. For wave calculations the water accelerations must be accounted, these procedures are described in section 3.2. 1.2.3 Design Details
Custom pressure gauge instruments were developed to fit the needs of this study. A major component of the gauges was the Model 85 pressure sensors from Measurement
Specialties (Figure 1-1a). These strain gauge type pressure sensors feature a small port to a stainless steel diaphragm for interfacing with seawater that is coupled to internal strain gauges through a thin silicon oil transfer medium. Attached to the strain gauges are two supply and two output wires. When force is applied to the diaphragm interface, as would result by increased water depth, this acts to stretch the Model 85’s
internal strain gauges changing their electrical resistance. When a small electrical
current is passed through the supply wires, the voltage across the output wires changes
15 linearly with the resistance of the internal strain gauges, and hence, the pressure on the diaphragm. This relationship between Voltage (V), Current (I) and Resistance (R) is given by Ohm’s Law
V = IR (1–3)
Another main component to the custom gauges designed in this study is the Tattletale TFX-11v2 remote data logger/ control engine made by Onset Computer Corporation shown in (Figure 1-1b). This data logger is a small programmable computer designed to autonomously run and record a device such as a pressure sensor. Custom
printed circuit boards (PCB) were made to interface between the TFX-11v2, the Model 85 pressure sensor, battery power and standard parallel and RS-232 desktop computer connections. This circuitry was modeled with a computer aided design program and sent to a PCB manufacturer. Surface mount electronic components are soldered onto the PCB’s resulting in a clean and reliable circuit. The important features of the custom PCBs are a low power supply current to the Model 85 and amplification of the pressure
sensor output voltage (Figure 1-2). The ratio of the PCB output to a regulated 5-volt reference is recorded by a 12-bit analog-to-digital converter on the TFX11-v2. This result is shifted 4 bits to the left and recorded as a 2-byte or 16-bit number into the TFX11-v2
internal flash storage. For example, an amplified pressure sensor output of 2.5 V is half the 5 V reference and is digitized as 212/2 *16 or 32768. The pressure gauges are
A Model 85 B TFX-11v2
Figure 1-1. Model 85 pressure sensor and TFX-11v2 data logger (A) Model 85 pressure sensor from Measurement Specialties (B) TFX-11v2 data logger by Onset Computer Corperation
16 powered with four 3.6 volt lithium ion batteries configured in two parallel pairs for a 7.2 volt supply.
Figure 1-2. Custom PCB amplifier schematic design. The labeled values indicate individual resistor and capacitor component values. The red circle indicates the location of the Model 85 pressure sensor and the label ”out” indicates the input to the TFX-11v2 analog to digital recorder
The data logger was programed to sample at 1 Hz or 1 sample per second. With each pressure sample requiring 2 bytes, the data logger’s 2 mega bytes of internal flash storage allowed 1,000,000 samples or 11.5 days of pressure samples to be recorded. This was enough memory to fully characterize a hurricane event which usually last 1-2 days, however, data storage expansion of the pressure gauges may be undertaken in future studies.
1.2.4 Calibration and Resolution
Each pressure gauge instrument was cross calibrated against a high precision
Paros Scientific transducer to obtain calibration coefficients. The coefficients are used to convert the recorded digital voltages to pressures. The basic procedure for
17 calibration connects the pressure sensor into a sealed loop that is shared with a high precision Paros Scientific transducer and two valves. The first valve is the feed and connects the loop to a regulated high pressure air tank, and the second valve is a bleed to release pressure from the loop. Starting with the bleed valve open, simultaneous samples are taken from the Paros and the custom pressure gauge. The bleed valve is then closed and the feed is opened inserting pressure into the loop and then closed. Another set of simultaneous samples are taken and recorded at this increased pressure. This process is continued up to 5000 millibars and then back down to ambient air pressure with the bleed valve open. Each calibration usually consisted of 10 to 15 points. The result after a least squares fit to the obtained points is a linear equation used to convert voltage to pascals. These least squares data fits were very good with the typical maximum absolute error between the fit and the data less than 5 millibars. The calibration coefficients for all deployments are listed in Table 1-1. The pressure wave and tide gauges resolution is found by dividing the 7500 millibar range of the transducer by the 12-bits A/D converter ( 4096 discrete values) for a result less than 2 millibars equivalent to 2 cm of water pressure. The true accuracy of the instrument is less than the resolution due to inherent noise in the circuitry. This noise has been measured to have a standard deviation of less than 4 millibars. There are other possible sources of error that will be discussed in the data processing section.
1.2.5 Gauge Housing and Anchoring Base
The data logger was isolated from moisture by sealing inside a water tight enclosure. This enclosure was made from 1.5 inch schedule 40 polyvinyl chloride (PVC) pipe. Machined threaded end caps allow the Model 85 pressure sensor (Figure 1-1) to screw in place and the diaphragm to interface with the external water pressure.
These threaded end caps also feature a rubber o-ring seat to further increase resistance to leakage. The opposite end of the enclosure remains open until the gauge is activated.
Inserting batteries activates the pressure gauges and this start time is documented
18 9000
8000
7000
6000
5000
4000
3000 Pressure in Milibars
2000
1000
0 0 1 2 3 4 5 6 7 4 A/D 2 byte conversion [0 − 65536] x 10 Figure 1-3. Example plot of study gauge cross-calibration with Paros Scientific pressure sensor. Red circles denote individual calibrations points and bold line is the least squares fit to data. The first order equation for this line gives the calibration coefficients to later synthesize a corresponding timeseries to the pressure data. After activation, a standard PVC end cap is fastened in place with blue waterproof PVC glue. The completed wave gauge is small at less than 8 inches in length. With more than 100 deployments and tests to date, zero gauges have leaked. The pressure sensors PVC enclosure housings are place inside weighted anchors bases. These 3 inch X 15 inch X 15 inch anchor bases are constructed with 3 inch channel steel and weigh approximately 50 pounds. The bases feature an armored compartment to hold the pressure sensor and an acoustic locator beacon. With only 3 inches height, this base design has proved to be low enough profile to withstand hurricane conditions. Another feature of the anchor bases is a 3 inch steel deployment ring and a tag line with small floats to aid in post storm recovery.
19 A B
Figure 1-4. (A) Pressure sensor and acoustic beacon inside anchor base with tag line and deployment ring (B) Underside of anchor base showing channels to mate with helicopter deployment sled
The first year of this study featured a different base design with four folding legs and a center post to carry the instrument. Four of these bases were deployed for tropical Storm Ernesto in 2006 but they are believed to have moved small distances during the wave event. Because the bases may have moved even though Tropical Storm Ernesto was not a very powerful storm, new improved low profile bases were designed and constructed for the following hurricane season.
1.3 Field Campaign
1.3.1 Helicopter Company Relations and Safety
There is only a small window of time availiable to deploy gauges ahead of an imminent hurricane landfall. This study relies on helicopters for expedient gauge deployment. Strict safety precautions are followed and the study is always placed behind maintaining the well being of the researchers. Each model helicopter has different characteristics such as top speed and cargo weight capacity, but all of the models generally observe the same upper limit for safe maximum wind conditions. If the conditions are not safe or at any time become unsafe, the deployment is canceled.
For cost issues several this study set up relations with several helicopter companies.
20 Ocean Helicopters Inc based out of Palm Beach is used for any storms near Florida. A tcomplication was finding Louisiana and Texas companies that are not presently obligated to shuttle oil rig workers back to land when for an approaching hurricane.
Austin Helijet did not have these oblication and is used for storms in Texas and western Louisiana. The project has also set up a relations with the Duke University out of North Caroline for hurricane strikes targeting further north along the east coast. Each separate company has to be met with for acquaintance with all aspects of the project. Setting up relations with helicopter companies ahead of time is crucial because departure notices were very short. Unexpected rapid hurricane intensification near coast may prove to be the most damaging as well as the hardest of the storms to intercept. With only a limited deployment budget, chasing weak storms or missing large ones are definite unwanted costs. Not executing a deployment for a large storm that comes in range is to be avoided at any price outside of safety. Preparation to be in position to execute well-informed decisions is all that can be asked for deployment.
1.3.2 Deployment
Figure 1-5. Helicopter deployment with detachable sled
The deployment of the pressure gauges requires the removal of one of the helicopters rear doors and installation of a custom seat. This seat features clips to attach a deployment sled when forward motion of the helicopter has eased (Figure 1-5).
21 This sled helps ensure the instrument clears the landing skids of the helicopter. The deployment process requires planned communication between the passenger and the helicopter pilot. Once the helicopter has reached the desired deployment location it lowers in to a hover at 20 feet elevation. The rear passenger records this location as a way point with hand held GPS. The instrument is placed onto the sled and held by a looped rope that has one end fasted to the helicopter (Figure1-5). When the instrument has been lowered to a level just above the water surface, the loose end of the rope is released and the instrument sinks to the sea bed. If there is any complications with tangling of the rope, sharp sheers are kept near by to cut the rope. Once the rope and sled are retrieved, the passenger informs the pilot to proceed to the next location”. The 2006 design featured bases with folding legs and did not used the deployment sled. These deployments required a self retrieving trigger string to activate the legs after the instrument had been lowered past the helicopter skids (Figure 1-6). Although these bases performed well they were deemed too bulky and improvement were made the following year.
Figure 1-6. Helicopter deployment of folding leg base
1.3.3 Retrieval
Returning to retrieve the gauges after a hurricane amongst the destruction debris can be an extensive process. The first step is to return by boat to the approximate
22 latitude and longitude recorded from Global Positioning System (GPS) during the deployment. There is usually no evidence of the pressure gauges from the sea surface.
The instruments are found by scuba divers carrying sonar receivers (Figure 1-7) that pick up the signal from the acoustic pinger locators attached to the pressure gauges. This recovery is added by a small line of marker floats attached to the pressure gauge. This has proven to be an effective method for instrument retrieval. Once located some minor digging is usually required to free the instruments, in a few cases a jet pump is was need to dig out the pressure sensors.
Figure 1-7. Scuba diver retrieval of pressure sensor
23 Table 1-1. Calibration Coefficients STORM SERIAL NUMBER SLOPE OFFSET ERNESTO 0942800 0.061347 924.15 ERNESTO 0942802 0.121501 195.26 ERNESTO 0942804 0.121644 221.92 ERNESTO 0942805 0.122397 197.25 NOEL 1109034 0.122169 251.95 NOEL 1109033 0.122960 219.39 NOEL 1005185 0.122214 200.86 NOEL 1031446 0.122354 179.73 NOEL 1109032 0.121657 202.73 NOEL 1109030 0.121743 228.20 FAY 1109038 0.121625 204.47 FAY 1031447 0.121640 072.63 FAY 1109032 0.121809 264.85 FAY 1181297 0.122348 -009.44 FAY 1005185 0.122708 170.81 GUSTAV 0942799 0.121325 207.88 GUSTAV 0942800 0.122741 201.25 GUSTAV 0942798 0.122170 222.32 GUSTAV 1031446 0.123388 011.58 GUSTAV 0942797 0.120890 213.26 GUSTAV 0942796 0.122582 181.41 GUSTAV 0942805 0.122195 262.25 GUSTAV 1181288 0.122058 -028.12 GUSTAV 1005190 0.121759 210.03 GUSTAV 1005189 0.121335 297.54 GUSTAV 1005183 0.122531 239.83 GUSTAV 0942802 0.122181 255.54 GUSTAV 1109030 0.121742 228.20 GUSTAV 1005191 0.121542 242.57 GUSTAV 1181283 0.121542 020.66 GUSTAV 1109036 0.120575 204.14 HANNA 1181287 0.122805 -006.06 HANNA 1181292 0.121585 113.58 HANNA 1031448 0.122137 219.14 HANNA 1181296 0.122311 089.73 IKE 1181300 0.122426 -009.70 IKE 1181298 0.122899 066.70 IKE 1181294 0.122022 203.46 IKE 1181304 0.122213 118.13 IKE 1109037 0.120712 403.35 IKE 1181301 0.120907 156.94 IKE 1109033 0.123082 216.94 IKE 1181295 0.121620 264.56 IKE 1181305 0.122179 592.29
24 CHAPTER 2 BACKGROUND AND GENERAL THEORY
2.1 Overview of Hurricanes
2.1.1 Climatology and Risk
The annual Atlantic hurricane season officially runs from June 1 through November 30 of each year and encompasses the North Atlantic Ocean, Caribbean Sea and the Gulf of Mexico. Hurricane activity in the Atlantic basin averages 4.2 named tropical storms and 5.2 hurricanes per year. Typically hurricanes form between the latitudes of 10◦and 30◦and require waters of at least 26◦C. The hurricane season coincides with high oceanic heat content in the Atlantic hurricane region, which peaks along with climatological hurricane activity a few weeks in advance of the sun’s autumnal equinox
in late September. The hurricane’s dependence on ocean heat as an energy source has
been analyzed as an atmospheric heat engine (Emanuel, 1988). It has been suggested that increases in hurricane activity in the Atlantic basin over the past decade was caused by anthropogenic climate change (Emanuel, 2005). Others argue that this man made
effect is very small and cannot be discerned from natural variability (Pielke et al., 2005). Aside from the total number of hurricanes, the greater concern of real consequence, is how many will hit land and affect inhabited coastal regions. In a given year, the chance of a major hurricane landfall at a specific coastal location is very small. The best estimate of this risk is based historical data are used for statistical calculation for hurricane return periods. As defined by the National Hurricane Center Risk Analysis Program (HURISK), the return period describes the average time expected between hurricanes occurrences within 75 nautical miles of a specific location. For example Galveston Texas has a return period of 25 years for a category 3 or greater storm, this means that on average 4 storms of at least this strength will pass within 75 nautical miles of that location in a 100 year period. Return periods are shown in figure 2-1 for locations from Texas to North Carolina. These values were estimated based on
25 historical tracks from 1886 to 1999 by HURISK. The 75 nautical mile radius used for the calculating the return period at a given location is based on a hurricane’s typical peripheral distance of influence.
Figure 2-1. HURISK category 3 hurricane 100 year return period map
2.1.2 Wind and Pressure Characteristics
The average pressure exerted by the earth’s atmosphere at sea level elevation is 1013 millibars 1 but can drop below 920 millibars in a very strong hurricane. Pressure gradients of this magnitude between the ambient sea level pressure and the hurricane central pressure can support surface wind speeds ( at 10 m elevation) exceeding 135 kt. An empirical relationship between the central pressure of a hurricane and the maximum wind speed (Stull, 1995) is given as
m V = 20 (kPa)−1/2 (P )1/2 , max s ∗ max (2–1)
1 The standard unit of pressure used by meteorologists, defined as 100 Pascals where Pa = N/m2
26 where Pmax is the difference between the ambient atmosphere and the central eye pressure. Hurricane winds rotate in a closed counter-clockwise cyclonic surface circulation about the storm eye or center that is visibly evident in satellite imagery.
The radial distance from the center of the hurricane to the strongest winds is called the radius to maximum winds Ro . This parameter is a simple measure of the hurricane size.
The wind speed decay beyond Ro can be approximated by (Stull, 1995)
V R0 1 = ( ) 2 . (2–2) Vmax R
According to this relation, wind speeds should be half that of the maximum at four times the radius to maximum winds. This maximum wind speed is relative to the center of the hurricane and must be superimposed with the forward translational speed of the entire storm. This usually leads to the most intense winds in the front right quadrant of a hurricane. Table 2-1. SAFFIR-SIMPSON HURRICANE WIND SCALE Wind Speed (kt) Classification 20-34 Tropical Depression 35-63 Tropical Storm 64-82 Category One Hurricane 83-95 Category Two Hurricane 96-113 Category Three Hurricane 114-135 Category Four Hurricane > 135 Category Five Hurricane
The Saffir-Simpson Hurricane Wind Scale (Table 2-1) classifies a storms destructive potential based on wind speed. This scale is not being used anymore for predicting storm surge since many other factors such as hurricane size, track, forward motion and coastal relief have proven to be of equal importance. After a storm has reached the threshold wind speed of a tropical storm, a name is assigned from a predetermined alphabetical list developed by the World Meteorological Organization. This naming system has the advantage of simplified communication and increased public awareness about storms that warrant caution. The names are reused every 6 years except for
27 any storm that causes catastrophe which is then replaced and retired. Three of the six storms studied for this research, Noel (2007), Gustav (2008) and Ike (2008) were retired from the list.
Figure 2-2. Satellite image of Hurricane Rita. This image depicts a well defined hurricane eye feature
2.2 The National Oceanic and Atmospheric Administration
The National Atmospheric and Atmospheric Administration (NOAA) serves as a public source of information on the ocean and atmosphere. NOAA is located directly under The United States Department of Commerce and houses 6 major line offices:
• Oceanic & Atmospheric Research (OAR)
• National Ocean Service (NOS)
• National Environmental Satellite, Date & Information Service (NESDIS)
• National Marine Fisheries Service (NMFS)
• National Weather Service (NWS)
• Program Planning and Integration (PPI)
28 Within the NWS is the National Centers for Environmental Prediction (NCEP) which houses the National Hurricane Center (NHC) / Tropical Prediction Center (TPC). The NHC/TPC makes public forecasts concerning hurricanes and is responsible for issuing watches and warnings for the public. This organizational structure prevents confusion about hurricanes by assigning one source for official guidance information. During this study, these updates were relied on to make decisions concerning response to a given storm. The NHC/TPC issues forecast track and intensity guidance every 6 hours for an active hurricane. The accuracy of these forecast is closely analyzed and current errors average 75 nautical miles for the 48 hour track forecasts. These errors have steadily improved from the 200 nautical mile averages only 2 decades ago. During this study, gauges were successfully positioned near landfall based on these forecasts. Typical deployments have had coastline coverage spanning well beyond the expected forecast errors ensuring the interception of the hurricane landfall. Although the track forecasting capabilities have improved considerably, the average intensity forecasts errors 48 hrs out has only slightly improved. Skill at forecasting rapid hurricane intensification 2 remains low. This can be a major concern near the coast as little time may remain for issuing watches, warnings or evacuation orders, and as this study is concerned, activating storm response.
2.3 Waves
2.3.1 Generation
Due to a strong relationship with wind, waves are considered to be part of the weather. Three basic principals are involved in the development of waves by wind:
• Intensity: The strength of the wind.
• Duration: The amount of time the wind blows.
2 A 30 knot increase in hurricane intensity within 24 hour period
29 • Fetch: The surface area affected by the wind.
Figure 2-3. Wave forecasting chart developed by Bretschnieder
2.3.2 Linear Equations
The major principal in linear wave theory is the dispersion relationship. This is basically a mathematical expression that relates the the wave length, the wave period and the water depth as follows.
σ2 = gktanh(kh) (2–3)
This relationship can also be displayed in graphical form, shown by figure 2-4.
30 50 320
140
220 60 160 380 120 260 280 360
180
100 240 45 300 340
200
20 40
40 80
35 Deep
320 30 220 140 260 280 60 160 300 240 120 180 25 100 200
Depth (m) 20 20 40 80
15 Transitional 220 140 160 180 200 10 120 60 100 5 80 Shallow 140 100 120 40 60 80 20 40 6040 020 04 06 08 10 12 14 16 18 20 Wave Period (s) Figure 2-4. Wave dispersion relation plot. Wavelength (m) as a function of wave period (s) and water depth (m)
2.3.3 National Data Buoy Center
Real-time observational marine and meteorological data are great importance to NOAA. The National Data Buoy Center (NDBC) is located within the NWS and maintains and operates over 100 operational real-time monitoring buoys and meteorological stations (Figure 2-5). This data is heavily used by the maritime community and NDBC has a close working relationship with the United States Coast Guard. The common parameters measured at NDBC stations are:
• WIND
• PRESSURE
• AIR AND WATER TEMPERATURE
• SOLAR RADIATION
31 • PRESSURE
• HUMIDITY
• WAVES
35º N
30º N
25º N
20º N
95º W 90º W 85º W 80º W 75º W
Figure 2-5. Map of National Data Buoy Center stations
Information gathered by these buoys is used by weather models and incorporated into the operational forecasts.
2.4 Tides
2.4.1 Harmonic Analysis of Tides
Tide observations from hardened land stations are combined and weighted to synthesize tides at the each study gauge site. From this point water levels are aligned before and post storm when there was little water level anomaly and conditions were
32 calm. With some certainty datum can be established and also predicted tides at stations gathered from the NOS synthetic. For Ike X the half meter settling is believed to have happened during the storm, this is corrected as linear settlement over several hours for the peak waves. Once this has been done the predicted tides can be subtracted from the study’s gauge stations to obtain the water level anomaly. Peak values above NAVD for absolute and also anomalous level can be gathered.
2.4.2 Astronomical vs Storm Tide
Following NOAA’s definitions, ”Storm surge is the onshore rush of sea or lake water caused by the high wind and the low pressure centers associated with a landfalling hurricane or other intense storm. The amplitude of the storm surge at any given location is dependent upon the orientation of the coast line with the storm track, the intensity, size and speed of the storm, and the local bathymetry. In practice, storm surge is usually estimated by subtracting the normal or astronomical tide from the observed storm tide at tide stations.” Storm surge is often confused with storm tide. This is defined by NOAA as, ”The maximum water level elevation measured by a water level station during storm events. Depending on location, the storm tide is the potential combination of storm surge, local astronomical tide, regional sea level variations and river runoff during storm events. Since wind generated waves ride on top of the storm surge (and are not included in the definition), the total instantaneous elevation may greatly exceed the predicted storm surge plus astronomical tide. It is potentially catastrophic, especially on low lying coasts with gently sloping offshore topography. NOAA measures storm tide elevations from a common reference datum of Mean Lower Low Water (MLLW) which is the U.S Nautical Chart Datum.” 2.4.3 National Ocean Service
Another NOAA agency that maintains real-time measurement stations is the
National Ocean Service (NOS). The NOS network essentially serves the same purpose as the NDBC, with each station collecting the same parameters with one major
33 distinction. NOS stations are located on shore in bays and estuaries or at the coast on structures and are surveyed to a vertical elevation datum. This reference datum is important for each station’s primary role of collecting tide measurements. Typically the
NOS tide stations do not measure wind waves. 2.4.4 United States Geological Survey
Located under the Department of the Interior, The United States Geological Survey (USGS) maintains an expansive network of real-time river level gauges. These act as an important tool monitoring floods and river discharge. When a hurricane impacts land heavy rainfall can occur over short periods of time and increase river levels substantially.
River flooding from inland rainfall and storm surge can combine at the coast and inside bays and estuary. The potential danger from these two processes acting together is an area of high interest. In addition to the permanent network of river stage monitoring stations the USGS has developed a rapid response storm surge program (McGee et al., 2005; East et al., 2008). The USGS program is focused on surge values overland and not at the open coast. These sensors are installed on hardened structures prior to hurricane landfalls. After the storm, the gauge sites are surveyed into an vertical elevation datum. These measurements are much like those available from the NOS stations and are not designed to measure waves. Collaboration between the this study and the USGS response team has already been establish. Wave surge pressure sensors will be installed at locations along with surge sensors at locations that may be impacted by waves. The USGS response teams have made deployments for Hurricanes Rita (2005), Wilma (2005), Ike (2008) and Gustav (2008). An excellent picture of sequence of events is available by combing the information obtained from this study’s nearshore stations and USGS stations at the coast.
34 CHAPTER 3 DATA ANALYSIS TECHNIQUES
3.1 Surge Processing
Atmospheric pressures oscillate slightly throughout the day, but are more heavily influenced by weather systems. Strong hurricanes have central pressures in the 950 millibar range, some 70 millibars below the surrounding atmospheric pressure. Therefore, in order to compute accurate water levels is crucial to use time dependent
atmospheric pressures Patm when calculating depth from the pressure timeseries Pabs
records. Ideally, as is done at National Ocean Service (NOS) stations, two gauges are
co-located with one recording Pabs and the other Patm to facilitate depth measurements. In the specific case of the project sites were offshore several km so having collocated
Patm gauges was not possible. Atmospheric pressure records from NOS stations are gathered at locations closest to the study gauge positions. These will not be exactly collocated with this study’s sites so some interpolations was required. The study’s gauge pressures that were measured
immediately prior to helicopter takeoff, maybe a half hour of readings, are compared with the atmospheric pressure measured at nearest NOS stations. A correction is applied so they match, this should be in the range of 1012 millibar standard atmospheric pressure. Next the interpolated NOS pressure files are subtracted from the study’s gauges pressures to get a differential pressure measurement between the atmosphere and the seabed. This pressure should start out at zero immediately prior to takeoff and then the rest of the record can be used for calculating water depths. This set of data is referenced to as water level data.
3.2 Wave Data Processing
Linear wave theory is the standard for most wave analysis applications. The principal behind linear wave theory is the ability to decompose waves into simple frequency components. The standard procedures behind this decomposition is spectral
35 analysis. The method typically used is know as the Fast Fourier Transform (FFT). The mathematical theory involved in the FFT is described by (Earle, 1996).
XL−1 i 2πmn X (j, mf ) = t x(j, nt)e− L (3–1) n=0 where L m = 0, 1, 2..., Leven 2 (3–2) L 1 m = 0, 1, 2..., − Lodd. 2 (3–3)
The real and imaginary parts of X are given by
XL−1 2 mn Re[(j, mf )] = t x(j, nt)cos( π ) − L (3–4) n=0
XL−1 2 mn Im[(j, mf )] = t x(j, nt)sin( π ) L (3–5) n=0 Spectral estimates are obtained at Fourier frequencies, mf , where the interval between frequencies is given by 1 f = Lt (3–6)
PSD estimates for the jth segment are given by
X ∗(j, mf )X (j, mf ) X (j, mf ) 2 S [(j, mf )] = = | | xx Lt Lt (3–7)
Final spectral estimates are obtained by averaging the results for all segments to obtain
XJ Sxx [(mf )] = Sxx [(j, mf )] (3–8) j=1
After wave spectra are calculated some verification is possible by comparing the integral of the spectra to the variance of the processed timeseries. Essentially, spectral analysis done with the FFT decomposes the timeseries into the variances of the
individual components frequencies. The significant wave height, the common parameter
used to describe ocean wave size, is equal to four times the square root of the integral of
36 the spectra. The significant wave height is defined as the average height of the largest 1/3 of all the decomposed waves. Another common parameter is the peak wave period. This defined as the most energetic portion of the decomposed wave spectra. These typical parameters are shown for each of the 6 storms measured for this study in the appendix section.
3.3 Liability Statement and Data Access
The data presented in this study is for educational purposes only. Further verification is required before applying data. It is suggested for those interested in specific aspects of the data to complete their own analysis. This data is open to the public and access can be gained through the web at http://kraken.coastal.ufl.edu.
37 APPENDIX A ERNESTO
Table A-1. Tropical Storm Ernesto deployment locations SERIAL NUMBER LATITUDE LONGITUDE 942800 26◦45.2390 80◦01.8220 942802 26◦41.7310 80◦01.2240 942804 26◦25.6240 80◦03.2530 942805 26◦02.4200 80◦05.9830
38 A National Hurricane Center Ernesto Advisory 16 issued 11am EDT 8/28/2006
B National Hurricane Center Ernesto Advisory 19 issued 5am EDT 8/29/2006
Figure A-1. National Hurricane Center forecast tracks for Tropical Storm Ernesto. Shown here are the last available forecast advisory prior to (A) field team activation and (B) deployment. 39 35º N 09/01
30º N 08/31
08/30 25º N
08/29
20º N 08/28 95º W 90º W 85º W 80º W 75º W
A Track. Open circles show position midday, closed midnight Eastern Daylight Time
70
CAT1 60
50
40 Windspeed ( Knots )
08/28 08/29 08/30 08/31 09/01 09/02
Date ( Central Daylight Time ) B Intensity. Maximum sustained winds (knots)
Figure A-2. Tropical Storm Ernesto track and Intensity
40 NDBC 41009 −800 28.4º N Trident Pier NOS −400
−80
−40
28.0º N
08/30 −800 18:00 27.6º N −400
−400
27.2º N −400 −80 −40
−80
−40
26.8º N 08/30 E4 12:00 E3 −80 −40 −400
26.4º N E2 −400
E1 −400 26.0º N −80
−40 08/30 −80 −80 −40 06:00 −800 Virginia Key NOS −400 −800 80.6º W 80.2º W 79.8º W 79.4º W 79.0º W
Figure A-3. Tropical Storm Ernesto deployment locations map. Southeast Florida gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 40, 80, 400 and 800 meter depths
41 2.5 2.0 1.5 1.0 0.5 E4 0.0 2.5 2.0 1.5 1.0 0.5 E3 0.0 2.5 2.0 1.5 1.0 0.5 E2 0.0
2.5 Significant Waveheight (meters) 2.0 1.5 1.0 0.5 E1 0.0 08/30 08/31 00:00 00:00 Date (Eastern Daylight Time)
Figure A-4. Wave height measurements for Tropical Storm Ernesto
42 .20 .15 .10 .05 E4 42009 .00 .20 .15 .10 .05 E3 .00 .20 .15 .10 .05
E2 Frequency (Hz) .00 .20 .15 .10 .05 E1 .00 08/30 08/31 00:00 00:00 Date (Eastern Daylight Time)
Figure A-5. Wave frequency measurements for Tropical Storm Ernesto
43 APPENDIX B NOEL
Table B-1. Hurricane Noel deployment locations SERIAL NUMBER LATITUDE LONGITUDE 1109030 27◦33.1440 80◦18.0100 1109032 27◦11.2250 80◦08.4250 1031446 26◦45.2270 80◦01.7710 1005185 26◦36.7190 80◦01.7280 1109033 26◦25.5280 80◦03.4080 1109034 26 ◦03.6030 80◦05.4860
44 A - National Hurricane Center Noel Advisory 8 issued 11am EDT 10/29/2007
B - National Hurricane Center Noel Advisory 11 issued 5am EDT 10/30/2007
Figure B-1. National Hurricane Center forecast tracks for Hurricane Noel. Shown here are the last available forecast advisory prior to (A) field team activation and (B) deployment. 45 35º N 11/03
30º N
11/02
25º N 11/01
10/31 10/30
20º N 95º W 90º W 85º W 80º W 75º W 10/29 A Track. Open circles show position midday, closed midnight Eastern Daylight Time
80
70 CAT1 60
50
Windspeed ( Knots ) 40
10/29 10/30 10/31 11/01 11/02 11/03 11/04 Date ( Central Daylight Time )
B Intensity. Maximum sustained winds (knots)
Figure B-2. Hurricane Noel track and Intensity
46 NDBC−80 41009 −40 −800 28.4º N Trident Pier NOS
−400
28.0º N
−800
27.6º N N6 Scripps 41114 −400 −80
−40
−80 −400 −80 27.2º N N5 −400 −40
26.8º N N4
Lake Worth Pier NOS N3 −40−80 26.4º N N2
N1 −400
−40 26.0º N −80 −80 −400 −80 Haulover Pier NOS −400 −40 Virginia Key NOS −800 −800 80.6º W 80.2º W 79.8º W 79.4º W 79.0º W
Figure B-3. Hurricane Noel deployment locations map. Southeast Florida gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 40, 80, 400 and 800 meter depths
47 2.0 1.0 N64111442009 0.0 2.0 1.0 N5 0.0 2.0 1.0 N4 0.0 2.0 1.0 N3 0.0 Significant Waveheight (meters) 2.0 1.0 N2 0.0 2.0 1.0 N1 10/31 11/01 11/02 11/03 11/040.0 00:00 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure B-4. Wave height measurements for Hurricane Noel
48 .20 .15 .10 .05 N64111442009 .00 .20 .15 .10 .05 N5 .00 .20 .15 .10 .05 N4 .00 .20 .15 .10 Frequency (Hz) .05 N3 .00 .20 .15 .10 .05 N2 .00 .20 .15 .10 .05 N1 .00 10/31 11/01 11/02 11/03 11/04 00:00 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure B-5. Wave frequency measurements for Hurricane Noel
49 APPENDIX C FAY
Table C-1. Tropical Storm Fay deployment locations SERIAL NUMBER LATITUDE LONGITUDE 1005185 25◦52.82400 81◦14.01600 1181297 26◦23.01000 82◦55.89600 1109032 26◦54.21000 82◦38.44800 1031447 27◦25.03800 82◦18.63000 1109038 27◦43.73400 82◦12.58200
50 A - National Hurricane Center Fay Advisory 4 issued 11am EDT 08/16/2008
B - National Hurricane Center Fay Advisory 7 issued 5am EDT 08/17/2008
Figure C-1. National Hurricane Center forecast tracks for Tropical Storm Fay. Shown here are the last available forecast advisory prior to (A) field team activation and (B) deployment. 51 35º N
08/25 08/24 08/23 30º N 08/22 08/21 08/20
08/19 25º N
08/18
20º N 08/17 08/16 95º W 90º W 85º W 80º W 75º W
A Track. Open circles show position midday, closed midnight Eastern Daylight Time
CAT1 60
50
40 Windspeed ( Knots )
08/17 08/18 08/19 08/20 08/21 08/22 08/23 08/24 08/25
Date ( Central Daylight Time ) B Intensity. Maximum sustained winds (knots)
Figure C-2. Tropical Storm Fay track and Intensity
52 Clearwater NOS
−20
27.8º N −10 E SAPF1 C−Cut NOS ANMF1
27.4º N D Scripps 42099 84.245º W −40 VENF1 27.0º N −20 −10 B
26.6º N −80
B BGCF1
26.2º N −40 −10 Naples NOS 08/19 −20 06:00
A 25.8º N
25.4º N 08/19
00:00 −10
−80
−40 83.6º W 83.2º W 82.8º W 82.4º W 82.0º W
Figure C-3. Tropical Storm Fay deployment locations map. Southwest Florida gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 10, 20, 40 and 80 meter depths
53 1.5 1.0 0.5 E42099 0.0 1.5 1.0 0.5 D 0.0 1.5 1.0 0.5 C 0.0 1.5 1.0 0.5
B Significant Waveheight (meters) 0.0 1.5 1.0 0.5 A 0.0 08/18 08/20 08/22 08/24 08/26 08/28 00:00 00:00 00:00 00:00 00:00 00:00
Date (Eastern Daylight Time)
Figure C-4. Wave height measurements for Tropical Storm Fay
54 .20 .15 .10 .05 E42099 .00 .20 .15 .10 .05 D .00 .20 .15 Frequency (Hz) .10 .05 C .00 .20 .15 .10 .05 B .00 .20 .15 .10 .05 A .00 08/18 08/20 08/22 08/24 08/26 08/28 00:00 00:00 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure C-5. Wave frequency measurements for Tropical Storm Fay
55 APPENDIX D GUSTAV
Table D-1. Hurricane Gustav deployment locations NAME SERIAL NUMBER LATITUDE LONGITUDE 01 0942799 29◦00.0600 90◦51.9060 02 0942800 29◦11.7440 91◦15.1190 04 0942798 29◦44.6420 93◦15.4930 05 1031446 29◦34.3660 92◦43.4390 06 0942797 29◦29.9620 92◦03.1910 07 0942796 29◦13.4390 91◦34.8070 08 0942805 29◦00.4150 90◦31.5780 09 1181288 29◦04.9580 90◦12.9100 11 1005190 29◦18.3710 89◦45.5890 12 1005189 29◦35.4340 88◦50.6910 13 1005183 29◦34.8190 89◦36.3380 14 0942802 29◦47.9220 89◦48.1420 17 1109030 30 ◦13.7430 89◦01.7470 18 1005191 30◦21.9590 86◦55.2720 19 1181283 30◦07.6270 87◦42.9090 20 1109036 30 ◦20.4800 86◦55.1950
56 A - National Hurricane Center Gustav Advisory 19 issued 11am EDT 08/29/2008
B - National Hurricane Center Gustav Advisory 22 issued 5am EDT 08/30/2008
Figure D-1. National Hurricane Center forecast tracks for Hurricane Gustav. Shown here are the last available forecast advisory prior to (A) field team activation and (B) deployment. 57 35º N 09/03
09/02
30º N
09/01
25º N 08/31
20º N 08/30
95º W 90º W 85º W 80º W 75º W 08/27 08/29 08/28 A Track. Open circles show position midday, closed midnight Central Daylight Time 135 120 CAT4 105 CAT3 90 CAT2 75 CAT1 60 Windspeed ( Knots ) 45 08/28 08/29 08/30 08/31 09/01 09/02 09/03 Date ( Central Daylight Time )
B Intensity. Maximum sustained winds (knots)
Figure D-2. Hurricane Gustav track and Intensity
58 30.8º N
18 30.4º N PCLF1 NOS −10 DPIA1 −20 −10 20 −10 17 −20 −40 −10 NDBC 42007 −20 −80 30.0º N 19
−40 −40 −40 29.6º N −20 −80 12 −400
−80 −400 −10 −800 29.2º N NDBC 42040 −400 −40−80 −800
28.8º N −800
−800
28.4º N
88.7º W 88.3º W 87.9º W 87.5º W 87.1º W
Figure D-3. Hurricane Gustav deployment locations map 1. East of the Mississippi river gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 10, 20, 40, 80, 400 and 800 meter depths
59 30.8º N
30.4º N WYCM1 NOS
30.0º N SHBL1 NOS 14
29.6º N 13 09/01 12:00 AMRL1 NOS 11 LUMC1 GISL1 NOS 29.2º N 02 −10
09 −20 01 08 −10 −10 −20 −10 PSTL1 NOS −40 −40 −80 28.8º N −20 −80
−20 −400 −40 −40009/01 −40 06:00 28.4º N
−800 −80 −80
91.1º W 90.7º W 90.3º−400 W 89.9º W 89.5º W
Figure D-4. Hurricane Gustav deployment locations map 2. Eastern Louisiana gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 10, 20, 40, 80, 400 and 800 meter depths
60 30.8º N
30.4º N
30.0º N
CAPL1 NOS 04 29.6º−10 N −10 −10 05 06 −10 AMRL1 NOS 16 km 29.2º N −10 −20 −20 07 −20 −20 28.8º N
−40 −40 −40 28.4º N
−80 −80 −80 93.5º W 93.1º W 92.7º W 92.3º W 91.9º W
Figure D-5. Hurricane Gustav deployment locations map 3. Western Louisiana gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 10, 20, 40, and 80 meter depths
61 2.0
1.0
0405 0.0
2.0
1.0
0607 42035 0.0
2.0
1.0
0201 0.0
2.0
1.0 Significant Waveheight (meters)
1413 0.0 09/01 09/02 09/03 09/04 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure D-6. Wave height measurements for Hurricane Gustav 1
62 .20 .15 .10 .05 0405 42035 .00 .20 .15 .10 .05 0607 .00 .20
.15 Frequency (Hz) .10 .05 0201 .00 .20 .15 .10 .05 1413 .00 08/31 09/01 09/02 09/03 09/04 12:00 12:00 12:00 12:00 12:00 Date (Eastern Daylight Time)
Figure D-7. Wave frequency measurements for Hurricane Gustav 1
63 4.0 3.0 2.0 1.0 0809 0.0 5.0 4.0 3.0 2.0 1.0 1112 42040 0.0 5.0 4.0 3.0 2.0 Significant Waveheight (meters) 1.0 1719 42007 0.0 5.0 4.0 3.0 2.0 1.0 1820 09/01 09/02 09/03 09/04 0.0 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure D-8. Wave height measurements for Hurricane Gustav 2
64 .20 .15 .10 .05 0809 .00 .20 .15 .10 .05 1112 42040 .00 .20
.15 Frequency (Hz) .10 .05 1719 42007 .00 .20 .15 .10 .05 1820 .00 08/31 09/01 09/02 09/03 09/04 12:00 12:00 12:00 12:00 12:00 Date (Eastern Daylight Time)
Figure D-9. Wave frequency measurements for Hurricane Gustav 2
65 APPENDIX E HANNA
Table E-1. Hurricane Hanna deployment locations NAME SERIAL NUMBER LATITUDE LONGITUDE G 1181292 35◦04.8840 75◦57.8340 H 1031448 34◦57.0780 76◦09.7440 J 1181300 34◦43.6560 76◦25.3200 E 1181287 34◦39.1200 76◦36.4680
66 A - National Hurricane Center Hanna Advisory 26 issued 5am EDT 09/03/2008
B - National Hurricane Center Hanna Advisory 27 issued 11am EDT 09/03/2008
Figure E-1. National Hurricane Center forecast tracks for Hurricane Hanna. Shown here are the last available forecast advisory prior to (A) field team activation and (B) deployment. 67 35º N
09/06
30º N
09/05
25º N
09/04
09/02
09/03 20º N
95º W 90º W 85º W 80º W 75º W
A Track. Open circles show position midday, closed midnight Eastern Daylight Time
70
CAT1 60
50
40 Windspeed ( Knots )
09/03 09/04 09/05 09/06 09/07
Date ( Central Daylight Time ) B Intensity. Maximum sustained winds (knots)
Figure E-2. Hurricane Hanna track and Intensity
68 Oregon Inlet NOS
33.2º N
−80 33.6º N −40 G −20 NDBC 41025 H −400−800 34.0º N Beaufort NOS J −40 E −20 −80
NDBC 41035−20 34.4º N
NDBC 41036 −40 −400 −80 −800 34.8º N
38.2º N −40 −80 −400 NDBC 41013
38.6º N −800
77.0º W 76.6º W 76.2º W 75.8º W 75.4º W
Figure E-3. Hurricane Hanna deployment locations map. North Carolina gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 20, 40, 80, 400 and 800 meter depths
69 4.0 3.0 2.0 1.0 G 41025 0.0 4.0 3.0 2.0 1.0 H 0.0 4.0 3.0 2.0 1.0 J Significant Waveheight (meters) 0.0 4.0 3.0 2.0 1.0 E 41035 41036 41013 0.0 09/06 09/07 09/08 09/09 00:00 Date00:00 (Eastern Daylight00:00 Time) 00:00
Figure E-4. Wave height measurements for Hurricane Hanna
70 .20 .15 .10 .05 G 41025 .00 .20 .15 .10 .05 H .00 .20
.15 Frequency (Hz) .10 .05 J .00 .20 .15 .10 .05 E 41035 41036 41013 .00 09/05 09/06 09/07 09/08 09/09 00:00 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure E-5. Wave frequency measurements for Hurricane Hanna
71 APPENDIX F IKE
Table F-1. Hurricane Ike deployment locations NAME SERIAL NUMBER PROXIMITY TO INLET ACCESS LATITUDE LONGITUDE Z 1181305 29◦35.08200 94◦07.5180 Y 1181295 29◦29.7840 94◦23.3040 X 1109033 29◦16.8780 94◦42.5400 W 1181301 29◦04.2840 95◦02.3760 V 1109037 28◦52.2240 95◦18.9060 U 1181304 28◦37.5060 96◦45.1440 S 1181294 28◦12.4620 96◦33.0240 R 1181298 27◦37.7340 96◦07.0560
72 A - National Hurricane Center Ike Advisory 30 issued 11am EDT 09/08/2008
B - National Hurricane Center Ike Advisory 38 issued 10am CDT 09/10/2008
Figure F-1. National Hurricane Center forecast tracks for Hurricane Ike. Shown here are the last available forecast advisory prior to (A) field team activation and (B) deployment. 73 09/14 35º N
30º N 09/13
09/12
09/11 25º N
09/10
09/09 09/08 09/07
20º N
95º W 90º W 85º W 80º W 75º W
A Track. Open circles show position midday, closed midnight Central Daylight Time
120 CAT4 105 CAT3 90 CAT2 75 CAT1 60
Windspeed ( Knots ) 45
09/08 09/09 09/10 09/11 09/12 09/13 09/14 Date ( Central Daylight Time )
B Intensity. Maximum sustained winds (knots)
Figure F-2. Hurricane Ike track and intensity
74 09/13 33.2º N 06:00
Sabine Pass NOS 33.6º N −10 Z −10 Y −10 Galveston Pier NOS −10 X 34.0º N NDBC 42035
W −20 09/13 −20 00:00 −10 34.4º N V −20 −20
−40 34.8º N −40 −40 09/12 18:00 −80 38.2º N −80 −80 NDBC 42019 −400 −400 38.6º−400 N
77.0º W 76.6º W 76.2º W 75.8º W 75.4º W
Figure F-3. Hurricane Ike deployment locations map 1. Northern Texas gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 10, 20, 40, 80 and 400 meter depths
75 33.2º N
33.6º N
34.0º N −10 U
−20 34.4º N
−10S −40 −20 34.8º N −40 −80
−10 R −400 38.2º N Corpus NOS
−20 −80
38.6º N −10
−40
−10 NDBC 42020
−400
77.0º W 76.6º W 76.2º W 75.8º W 75.4º W −20
Figure F-4. Hurricane Ike deployment locations map 2. Southern Texas gauge locations shown with black circles, NOS stations with blue squares, NDBC buoys with blue diamonds. Also shown are contours for the 10, 20, 40, 80 and 400 meter depths
76 5.0 4.0 3.0 2.0 1.0 Y Z 0.0 5.0 4.0 3.0 2.0 1.0 W X 42035 0.0 5.0 4.0 3.0 2.0 Significant Waveheight (meters) 1.0 U V 42019 0.0 5.0 4.0 3.0 2.0 1.0 R S 42020 0.0 09/11 09/12 09/13 09/14 09/15 09/16 00:00 00:00 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure F-5. Wave height measurements for Hurricane Ike
77 .20 .15 .10 .05 Y Z .00 .20 .15 .10 .05 W X 42035 .00 .20
.15 Frequency (Hz) .10 .05 U V 42019 .00 .20 .15 .10 .05 R S 42020 .00 09/11 09/12 09/13 09/14 09/15 09/16 00:00 00:00 00:00 00:00 00:00 00:00 Date (Eastern Daylight Time)
Figure F-6. Wave frequency measurements for Hurricane Ike
78 REFERENCES Bergan, P. O., Torum, A., & Traetteburg, A. (1968). Wave measurements by a pressure type wave gauge. 10th Conference on Coastal Engineering.
Bishop, C. T., & Donelan, M. A. (1987). Measuring waves with pressure transducers. Coastal Engineering, 11, 309–328.
Earle, M. D. (1996). Nondirectional and directional wave data analysis procedures. NDBC Technical Document 96-01.
East, J. W., Turco, M. J., & Mason, R. R. (2008). Monitoring inland storm surge and flooding from hurricane ike. U.S. Geological Survey Open-file Report.
Emanuel, K. A. (1988). The maximun intensity of hurricanes. Journal of the Atmospheric Sciences, 45(7).
Emanuel, K. A. (2005). Emanual replies. NATURE, 438, E13. Fan, Y., Ginis, I., Hara, T., Wright, C. W., & Walsh, E. J. (2009). Numerical simulations and observations of surface wave fields under an extreme tropical cyclone. Journal of Physical Oceanography, 39, 2097–2116. Harris, D. L. (1963). Characteristics of hurricane storm surge. Tech. rep., U.S. Weather Bureau.
Masters, F. J., Tieleman, H. W., & Balderrama, J. A. (2010). Surface wind measurements in three gulf coast hurricanes of 2005. Journal of Wind Engineering and Industrial Aerodynamics, In press. McGee, B. D., Goree, B. B., Tollett, R. W., Woodward, B. K., & Kress, W. H. (2005). Hurricane rite surge data, southwestern louisiana and northeastern texas. U.S. Geological Survey Data Series 220.
Pielke, R. A., Lannsea, C., Mayfield, M., Laver, J., & Pasch, R. (2005). Hurricanes and global warming. Bulletin of the American Meteorological Society, 86(11), 1571–1575. Skwira, G. D., Schroeder, J. L., & Peterson, R. L. (2005). Surface observations of landfalling hurricanes. Monthly Weather Review, 133, 454–466. Stull, R. B. (1995). Meterology Today for Scientists and Engineers. West Publishing Company.
Wang, D., & Oey, L. (2008). Hindcast of waves and currents in hurricane katrina. Bulletin of the American Meteorological Society, (pp. 487–495). White, G., & Buckingham, B. (1999). Weather buoys are vital but vulnerable. Spaceport News, 38(26).
79 BIOGRAPHICAL SKETCH Uriah Gravois was born in Citra, Florida on the south shore of Orange Lake. Many of his childhood days were spent fishing and taking part in other outdoor activities.
Uriah attended high school at P.K. Yonge in Gainesville, Florida. He was proud to be a ”Blue Wave” and played on the soccer and golf teams. Golf continued to be a big part of his life and he worked at the golf course at the University of Florida for over 4 years, however, this hobby was replaced by a bigger love for surfing. After attending Santa Fe Community College for two years, Uriah earned an Associate of Science in biomedical engineering technology and a general Associate of Arts degree to transfer into the University of Florida’s College of Engineering. The electronics experience helped him gain a position as a University Scholar working with the Department of
Civil and Coastal Engineering. Now that Uriah has completed his bachelor’s degree and Master of Science, he plans to continue towards PhD Degree at the University of Florida’s College of Engineering in the Department of Civil and Coastal Engineering.
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