Cyclones : Background, History and Impact [1 ed.] 9781608767113, 9781606920640

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Copyright © 2009. Nova Science Publishers, Incorporated. All rights reserved.

NATURAL DISASTER RESEARCH, PREDICTION AND MITIGATION SERIES

CYCLONES: BACKGROUND, HISTORY AND IMPACT

Copyright © 2009. Nova Science Publishers, Incorporated. All rights reserved.

No part of this digital document may be reproduced, stored in a retrieval system or transmitted in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.

NATURAL DISASTER RESEARCH, PREDICTION AND MITIGATION SERIES The Phoenix of Natural Disasters: Community Resilience Kathryn Gow and Douglas Paton (Editors) 2008. ISBN: 978-1-60456-161-6 Natural Disasters: Public Policy Options for Changing the Federal Role in Natural Catastrophe Insurance United States Government Accountability Office 2008. ISBN: 978-1-60456-717-5 Solar Activity and Forest Fires Milan Rodovanovic and Joao Fernando Pereira Gomes 2009. ISBN: 978-1-60741-002-7 National Emergency Responses Paul B. Merganthal (Editor) 2009. ISBN: 978-1-60692-354-2 Earthquakes: Risk, Monitoring and Research Earl V. Leary (Editor) 2009. ISBN: 978-1-60692-648-2 Hurricane Katrina: Impact, Recovery and Lessons Learned Nessa P. Godfrey (Editor) 2009. ISBN: 978-1-60692-478-5

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Cyclones: Background, History and Impact Terrance G. LaBeau (Editor) 2009. ISBN: 978-1-60692-064-0

NATURAL DISASTER RESEARCH, PREDICTION AND MITIGATION SERIES

CYCLONES: BACKGROUND, HISTORY AND IMPACT

TERRANCE G. LABEAU

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EDITOR

Nova Science Publishers, Inc. New York

Copyright © 2009 by Nova Science Publishers, Inc. All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Available upon request

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ISBN: 978-1-60876-711-3 (E-Book)

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CONTENTS Preface Chapter 1

Cyclones: Facts and History Hurricane Research Division

Chapter 2

The Ability of Climate Models to Generate Tropical Cyclones: Implications for Prediction Kevin Walsh

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Effect of Uncertainties in Modeling Tropical Cyclones on Pricing Excess of Loss Reinsurance Siamak Daneshvaran and Robert E. Morden

207

The Impacts of an Increase in Tropical Cyclone Activity on Tourism in Mauritius Sobhee Sanjeev

221

Chapter 3

Chapter 4

Chapter 5 Index

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vii

Cyclone Nargis and Burma’s Constitutional Referendum Michael F. Martin and Rhoda Margesson

1

237 257

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PREFACE In meteorology, a cyclone refers to an area of closed, circular fluid motion rotating in the same direction as the Earth[1][2]. This is usually characterized by inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth.Cyclogenesis describes the process of cyclone formation and intensification. Extratropical cyclones form as waves in large regions of enhanced midlatitude temperature contrasts called baroclinic zones. Weather fronts separate two masses of air of different densities and are associated with the most prominent meteorological phenomena. Air masses separated by a front may differ in temperature or humidity. Strong cold fronts typically feature narrow bands of thunderstorms and severe weather, and may on occasion be preceded by squall lines or dry lines. They form west of the circulation center and generally move from west to east. Warm fronts form east of the cyclone center and are usually preceded by stratiform precipitation and fog. They move poleward ahead of the cyclone path. Occluded fronts form late in the cyclone life cycle near the enter of the cyclone and often wrap around the storm center. Chapter 1 - This FAQ (Frequently Asked Questions) web site attempts to address various questions regarding hurricanes, typhoons and tropical cyclones that have been posed to us as hurricane researchers over the years. While it is not intended to be a technical guide, references are given throughout the FAQ for those that would like additional, detailed information. Also, there is no guarantee that all that is in here is completely accurate (we're human!). If you do see an item that needs correction, or if you have any additional questions that you think should be added to this FAQ, please contact us directly. Chapter 2 - Climate models are the main tools used for predicting the effect of global warming. Recently, these models have developed an increasingly sophisticated ability to simulate tropical cyclones, a very demanding task due to the relatively small size and the intense convection of these storms. This paper gives an evaluation of the state of the art of tropical cyclone climate modeling, including an examination of our current ability to simulate the correct numbers, structure and intensities of cyclones. The shortcomings of present models are outlined as well as specific recommendations for ways in which they can be improved. Additionally, a summary of current model-based predictions of the effects of global warming on tropical cyclones is given, including an assessment of how the uncertainty of these predictions might be reduced through improved simulation. Chapter 3 - Recently, improved understanding of catastrophe exposure is providing the private sector with better tools to quantify their risk. Many insurance companies realize the

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Terrance G. LaBeau

level of their exposure concentration and reinsurance companies immediately respond to this increase in exposure by radically raising rates. This increase in rate along with the increase of the attachment points/retentions pressures the insurance companies and as result the policyholders. The probable scenario losses estimated by catastrophe models for Florida are on the order of $70 billion. Given their capacity, insurance industry in general is reluctant/unable to absorb losses due to such large events and the majority of the loss will be self insured by the owners. In an effort to reduce/mitigate this risk, reinsurance is widely used. In this study the focus is a typical excess of loss reinsurance. Among the benefits of the excess of loss reinsurance is helping to stabilize the losses to the primary insurers and enable them to write larger risks. Catastrophe modeling software is generally used as an input to estimate the price of insurance layers. These models, in a probabilistic framework, use science and engineering methods in combination with the observed/recorded data. These models are capable of producing scenario results as well as probabilistic results (PML curves). Both the average annual loss and PML curves (results of probabilistic analysis) are important in pricing reinsurance layers Chapter 4 - This chapter tries to fill up a specific gap in the literature on climate change and tourism. Generally speaking, research works in this area tend to focus more on the potential threats of climate change to Small Island Developing States (SIDS), and their tourism sector, in particular, through sea-level rise, loss of bays and distorted coastal morphology. However, we take a different approach by ascertaining potential marginal losses of the tourism sector for the island of Mauritius should there be an increase in tropical cyclone activity in the South West Indian Ocean. Indeed, two objectives are set to achieve this aim and to fill up this gap. Firstly, an empirical demand function for tourism is estimated and, secondly, alternative scenarios of tropical cyclone are created and simulated results are derived. The recreational demand function based on a singlesite travel cost model is estimated using panel data pertaining to tourist arrivals from 14 countries spanning across a period of 17 years (1987-2003). Our findings show that a one percentage point increase in tropical cyclone activity in this corner of the world would induce a marginal loss of $5.3mn, representing a loss of 0.8% of overall receipts from tourism in 2003. Chapter 5 - Cyclone Nargis struck the coast of Burma in the evening of May 2, 2008 and cut a path of destruction across the southern portion of the country. The storm left in its wake at least 22,000 dead, 41,000 more missing, and extensive damage to the nation’s premier agricultural areas. Some have speculated that the final number of dead could reach 100,000. Vital infrastructure was destroyed by the storm, severely limiting the ability to assess the loss of life and provide assistance to the survivors. In addition, much of Burma’s most productive agricultural land has been severely damaged; some experts expect that it will take up to two years for Burma’s production of rice, seafood, pork and poultry to recover, and that the nation may face chronic food shortages and the need for international assistance for many months. Burma’s ruling military junta quickly faced both domestic and international criticism for its response to Cyclone Nargis, including accusations that it failed to provide adequate warning, its slow emergency response, and its reluctance to allow international relief workers into the country. The United States has offered $3.25 million in relief aid, and is willing to send in relief teams, if they can secure the necessary visas from the junta.

Preface

ix

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Even before Cyclone Nargis struck, the junta was already facing a highly controversial referendum on a proposed constitution scheduled for May 10, 2008 that could shape U.S. and other countries’ policies toward Burma. As a consequence, the evolution and implications of the humanitarian crisis are inextricably linked to Burma’s political situation and its relations with the international community. In a widely criticized move, although the military junta decided to postpone the vote for two weeks in some of the more damaged areas of Burma, it indicates it still intends to hold the constitutional referendum in most of Burma on May 10, 2008. Critics have called for the cancellation or postponement of the vote for all of Burma. In addition, some experts are speculating that Cyclone Nargis may precipitate major political change in Burma, including the destabilization of Burma’s military regime. The junta was already under domestic and international pressure to cancel the constitutional referendum. Local dissatisfaction with the speed and quality of the junta’s provision of emergency assistance may heighten domestic opposition to the junta and its proposed constitution. Also, rising food prices and food shortages may feed popular discontent, much like fuel price increases led to protests in Burma of September 2007. This report examines the scope of and response to the disaster, as well as its links to Burma’s political situation and U.S. policy. The report will be updates as circumstances warrant.

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In: Cyclones: Background, History and Impact Editor: Terrance G. LaBeau

ISBN: 978-1-60692-064-0 © 2009 Nova Science Publishers, Inc.

Chapter 1

CYCLONES: FACTS AND HISTORY* National Oceanic and Atmospheric Administration INTRODUCTION

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This article attempts to address various questions regarding hurricanes, typhoons and tropical cyclones that have been posed to us as hurricane researchers over the years. While it is not intended to be a technical guide, references are given throughout the FAQ for those that would like additional, detailed information. Also, there is no guarantee that all that is in here is completely accurate (we're human!). Hopefully, this article can help answer some of the questions that you may have about the characteristics of these catastrophic storms, how they are monitored and forecasted, and what are some of research topics that are being addressed today. We'd like to thank various people for helping to put this together: Sim Aberson, Jack Beven, Gary Padgett, Tom Berg, Julian Heming, Gary Gray, Frank Woodcock, Stephen Caparotta, Steven Young, D. Walston, James Lewis Free, Jon Gill, Miles Lawrence, Robert A. Black, Bill McCaul, Bart Hagemeyer, Frank Marks, Joe Cione, Frank Lepore, and John Guiney, all provided substantial bits to this FAQ. Many thanks also to Jan Null for providing the first .html version of the FAQ. Chris Landsea Neal Dorst Erica Rule

*

This is an edited, excerpted and augmented edition of a National Oceanic and Atmospheric Administration publication extracted from http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqHED.html

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National Oceanic and Atmospheric Administration

A. BASIC DEFINITIONS A1. What Is a Hurricane, Typhoon, or Tropical Cyclone?

Contributed by Chris Landsea

The terms "hurricane" and "typhoon" are regionally specific names for a strong "tropical cyclone". A tropical cyclone is the generic term for a non-frontal synoptic scale low-pressure system over tropical or sub-tropical waters with organized convection (i.e. thunderstorm activity) and definite cyclonic surface wind circulation (Holland 1993). Tropical cyclones with maximum sustained surface winds of less than 17 m/s (34 kt, 39 mph) are called "tropical depressions" (This is not to be confused with the condition midlatitude people get during a long, cold and grey winter wishing they could be closer to the equator ;-)). Once the tropical cyclone reaches winds of at least 17 m/s (34 kt, 39 mph) they are typically called a "tropical storm" and assigned a name. If winds reach 33 m/s (64 kt, 74 mph)), then they are called: • • •

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• • •

"hurricane" (the North Atlantic Ocean, the Northeast Pacific Ocean east of the dateline, or the South Pacific Ocean east of 160E) "typhoon" (the Northwest Pacific Ocean west of the dateline) "severe tropical cyclone" (the Southwest Pacific Ocean west of 160E or Southeast Indian Ocean east of 90E) "severe cyclonic storm" (the North Indian Ocean) "tropical cyclone" (the Southwest Indian Ocean) (Neumann 1993).

A2. What Is a "Cape Verde" Hurricanes?

Contributed by Chris Landsea Cape Verde-type hurricanes are those Atlantic basin tropical cyclones that develop into tropical storms fairly close ( 80 F or 26.5 C) waters to help maintain the hurricane. However, along the U.S. west coast, the ocean temperatures rarely get above the lower 70s, even in the midst of summer. Such relatively cool temperatures are not energetic enough to sustain a hurricane's strength. So for the occasional Northeast Pacific hurricane that does track back toward the U.S. west coast, the cooler waters can quickly reduce the strength of the storm. Recently (Chenoweth and Landsea, 2004), it was re-discovered that a hurricane struck San Diego, California on October 2, 1858. Unprecedented damage was done in the city and was described as the severest gale ever felt to that date nor has it been matched or exceeded in severity since. The hurricane force winds at San Diego are the first and only documented instance of winds of this strength from a tropical cyclone in the recorded history of the state. While climate records are incomplete, 1858 may have been an El Nino year, which would have allowed the hurricane to maintain intensity as it moved north along warmer than usual waters. Today if a Category 1 hurricane made a direct landfall in either San Diego or Los Angeles, damage from such a storm would likely be on the order of a few to several hundred million dollars. The re-discovery of this storm is relevant to climate change issues and the

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insurance/emergency management communities risk assessment of rare and extreme events in the region.

G9. How Much Lightning Occurs in Tropical Cyclones?

Contributed by Chris Landsea

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Surprisingly, not much lightning occurs in the inner core (within about 100 km or 60 mi) of the tropical cyclone center. Only around a dozen or less cloud-to-ground strikes per hour occur around the eyewall of the storm, in strong contrast to an overland mid-latitude mesoscale convective complex which may be observed to have lightning flash rates of greater than 1000 per hour maintained for several hours. Hurricane Andrew's eyewall had less than 10 strikes per hour from the time it was over the Bahamas until after it made landfall along Louisiana, with several hours with no cloud-toground lightning at all (Molinari et al. 1994). However, lightning can be more common in outer cores of storms (beyond 100 km or 60 mi) with flash rates on the order of 100s per hour. This lack of inner core lightning is due to the relative weak nature of the eyewall thunderstorms. Because of the lack of surface heating over the ocean ocean and the "warm core" nature of the tropical cyclones, there is less buoyancy available to support the updrafts. Weaker updrafts lack the super-cooled water (e.g. water with a temperature less than 0° C or 32° F) that is crucial in charging up a thunderstorm by the interaction of ice crystals in the presence of liquid water (Black and Hallett 1986). The more common outer core lightning occurs in conjunction with the presence of convectively-active rainbands (Samsury and Orville 1994). One of the exciting possibilities that recent lightning studies have suggested is that changes in the inner core strikes - though the number of strikes is usually quite low - may provide a useful forecast tool for intensification of tropical cyclones. Black (1975) suggested that bursts of inner core convection which are accompanied by increases in electrical activity may indicate that the tropical cyclone will soon commence a deepening in intensity. Analyses of Hurricanes Diana (1984), Florence (1988) and Andrew (1992), an unnamed tropical storm in 1987 indicate that this is often true (Lyons and Keen 1994 and Molinari et al. 1994).

G10. What Is the 20th Century Hurricane Record for Each U.S. Coastal County?

Contributed by Chris Landsea The NOAA Coastal Services Center provides an on-line revision to the original NOAA technical memorandum by Jarrell et al. 1992. One can query for any U.S. coastal county and obtain a graph with hurricane strikes and population changes. This information lets users know how many and how often hurricanes have struck, what Saffir- Simpson Hurricane Scale category they were, and how the populations have changed during the 20th Century.

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G11. What Is My Chance of Being Struck by a Tropical Storm or Hurricane?

Contributed by Chris Landsea

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The figure here shows for any particular location what the chance is that a tropical storm or hurricane will affect the area sometime during the whole June to November hurricane season. We utilized the years 1944 to 1999 in the analysis and counted hits when a storm or hurricane was within about 100 miles (165 km). This figure is created by Todd Kimberlain.

For example, people living in New Orleans, Louisiana have about a 40% chance (the green-orange color) per year of experiencing a strike by a tropical storm or hurricane. For the U.S., the locations that have the highest chances are the following: Miami, Florida - 48% chance; Cape Hatteras, North Carolina - 48% chance; and San Juan, Puerto Rico - 42% chance. For any particular location the chance that a hurricane will directly affect the area sometime during the whole June to November hurricane season is shown below. We utilized the years 1944 to 1999 in the analysis and counted hits when a hurricane was within about 60 miles (110 km). This figure is created by Todd Kimberlain. (For example, the chance for Miami, Florida is about 16%.) For any particular location what the chance is that a major hurricane (Category 3, 4 or 5) will directly affect the area sometime during the whole June to November hurricane season is shown in the figure below. We utilized the years 1944 to 1999 in the analysis and counted hits when a hurricane was within about 30 miles (50 km). This figure is created by Todd Kimberlain. (For example, the chance for Miami, Florida is about 4%.)

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134 National Oceanic and Atmospheric Administration

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Many folks are are concerned about the possible impacts that a hurricane could have on their vacation. If so, please check with your hotel, cruise company, etc. to find out how they inform their guests when a hurricane is coming, what actions they plan and what refund policies they have (if any). Keep in mind that a direct hit by a major hurricane is an extremely rare event and if I had a chance - for example - to go on a cruise in the Caribbean Sea during hurricane season, I would go without hesitation.

G12. What Is My Chance of Having a Tropical Storm or Hurricane Strike by Each Month?

Contributed by Chris Landsea The following table shows that for at any particular location what the chance that a tropical storm or hurricane will affect the area sometime during an individual month. We utilized the years 1944 to 1999 in the analysis and counted hits when a storm or hurricane was within about 100 miles (165 km). Many folks are are concerned about the possible impacts that a hurricane could have on their vacation. If so, please check with your hotel, cruise company, etc. to find out how they inform their guests when a hurricane is coming, what actions they plan and what refund policies they have (if any). Keep in mind that a direct hit by a major hurricane is an extremely rare event and if I had a chance - for example - to go on a cruise in the Caribbean Sea during hurricane season, I would go without hesitation. All Named Storms June July August September October November

Hurricanes June July August September October November

Major Hurricanes None None August September October None

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These figures were created by Todd Kimberlain.

G13. What Is the Average Number of Tropical Storms and Hurricanes to Affect My Town?

Contributed by Chris Landsea The figure below (created by Todd Kimberlain) shows for any particular location what the average number of tropical storms and hurricanes is that affect the area sometime during the whole June to November hurricane season. We utilized the years 1944 to 1997 in the analysis and counted hits when a storm or hurricane was within about 100 miles (165 km).

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G14. What Is the Peak Number of Tropical Storms and Hurricanes to Affect My Town?

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Contributed by Chris Landsea The figure below (created by Todd Kimberlain) shows for any particular location what the highest number of tropical storms and hurricanes is that affect the area sometime during the whole June to November hurricane season. Blue indicates a peak of just 1 storm, orange is 2 storms, brick red is 3 storms, green is 4 storms and red is 5 storms. We utilized the years 1944 to 1997 in the analysis and counted hits when a storm or hurricane was within about 100 miles (165 km).

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G15. I'm Vacationing in the Caribbean/the Bahamas/ Central America/Miami or Elsewhere in the Tropics During Hurricane Season. What's My Chance of Getting Hit by a Hurricane?"

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Contributed by Chris Landsea Typically, for someone visiting the tropics during June through November, the chance to experience (or even be threatened by) a hurricane is very small. As an example, this figure shows the chances to have a direct hit by a hurricane during the month of September, which is usually the busiest month. If we look at Puerto Rico, the chance is 8% of experiencing a hurricane, if you are there for the WHOLE month. If you are there for, say, only a week, then the chance would be one fourth of that - or only about 2% chance. To put this into perspective, if you made 50 one week trips to Puerto Rico in September, you would only experience a direct hit in ONE of those 50 visits. So the chances to get impacted by a hurricane are quite small for relatively short trips. (And the case chosen here is the WORST possible, as all other locations in all other months have smaller chances of being hit by a hurricane.) If you would like to see chances of hurricane strikes in other months, see Question G12.

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Despite the chance being small, one should know in advance what your hotel's, cruise company's, etc. policy is for guests when a hurricane is coming, what actions they plan and what refund policies they have (if any). As is described above, a direct hit by a hurricane is a very rare event for a short visit and if I had a chance - for example - to go on a cruise in the Caribbean Sea during hurricane season, I would go without hesitation.

G16. What Is the Average Forward Speed of a Hurricane?

Contributed by Neal Dorst The forward speed of hurricanes is very latitude dependent. Typically, Atlantic hurricanes track along the western side of the subtropical ridge in the western Atlantic. As they recurve (turn more northerly) from their westward track they usually slow down. If they reach the midlatitudes, they can interact with upper-level troughs and pick up speed.

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In the table below, the forward speed of hurricanes in the HURDAT database have been averaged in 5 degree latitude bins : Forward speed of Atlantic hurricanes averaged by 5 degree latitude bins

Latitude bin 0°- 5°N 5°-10°N 10°-15°N 15°-20°N 20°-25°N 25°-30°N 30°-35°N 35°-40°N 40°-45°N 45°-50°N 50°-55°N 55°-60°N

Storm Speed km/hr knt 25.5 13.7 21.8 11.8 19.6 10.6 17.7 9.5 17.7 9.5 20.1 10.9 27.6 14.9 38.5 20.8 46.7 25.2 51.4 27.7 51.4 27.8 55.8 30.1

No. mph 15.8 13.6 12.2 11.0 11.0 12.5 17.2 23.9 29.0 32.0 32.0 34.7

Cases 100 3282 5808 6086 6817 5321 2835 1026 263 36 15 1

While there are many cases where the forward speed over the 6 hour interval in the hurricane database is zero, such as Mitch in 1998, the highest speed in the database is for unnamed Tropical Storm #6 in 1961. As it got caught up by a midlatitude trough over the midatlantic states, it went speeding off northeastward over Maine and New Brunswick at a maximum speed of 112.25 km/hr (60.57 knt or 69.75 mph). The fastest hurricane in the record was Emily in 1987, whose maximum speed reached 110.48 km/hr (59.61knt or 68.65 mph) as it raced over the North Atlantic, before it turned extratropical.

H. TROPICAL CYCLONE OBSERVATION

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H1. What Is the Dvorak Technique and How Is It Used?

Contributed by Chris Landsea The Dvorak technique is a methodology to get estimates of tropical cyclone intensity from satellite pictures. Vern Dvorak developed the scheme using a pattern recognition decision tree in the early 1970s (Dvorak 1975, 1984) . Utilizing the current satellite picture of a tropical cyclone, one matches the image versus a number of possible pattern types: Curved band Pattern, Shear Pattern, Eye Pattern, Central Dense Overcast (CDO) Pattern, Embedded Center Pattern or Central Cold Cover Pattern. If infrared satellite imagery is available for Eye Patterns (generally the pattern seen for hurricanes, severe tropical cyclones and typhoons), then the scheme utilizes the difference between the temperature of the warm eye and the surrounding cold cloud tops. The larger the difference, the more intense the tropical cyclone is estimated to be. From this one gets a "T-

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number" and a "Current Intensity (CI) Number". CI numbers have been calibrated against aircraft measurements of tropical cyclones in the Northwest Pacific and Atlantic basins. On average, the CI numbers correspond to the following intensities:

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Current Intensity Numbers Maximum Sustained CI Number One Minute Winds (kts) 0.0