Explaining the Trends and Variability in the United States Tornado Records
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(QBO) Impact on the Boreal Winter Polar Vortex
https://doi.org/10.5194/acp-2019-1119 Preprint. Discussion started: 14 January 2020 c Author(s) 2020. CC BY 4.0 License. A tropospheric pathway of the stratospheric quasi-biennial oscillation (QBO) impact on the boreal winter polar vortex Koji Yamazaki1, Tetsu Nakamura1, Jinro Ukita2, and Kazuhira Hoshi3 5 1Faculty of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan 2Faculty of Science, Niigata University, Niigata, 950-2181, Japan 3Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan 10 Correspondence to: Koji Yamazaki ([email protected]) Abstract. The quasi-biennial oscillation (QBO) is quasi-periodic oscillation of the tropical zonal wind in the stratosphere. When the tropical lower stratospheric wind is easterly (westerly), the winter Northern Hemisphere (NH) stratospheric polar vortex tends to be weak (strong). This relation is known as Holton-Tan relationship. Several mechanisms for this relationship have been proposed, especially linking the tropics with high-latitudes through stratospheric pathway. Although QBO impacts 15 on the troposphere have been extensively discussed, a tropospheric pathway of the Holton-Tan relationship has not been explored previously. We here propose a tropospheric pathway of the QBO impact, which may partly account for the Holton- Tan relationship in early winter, especially in the November-December period. The study is based on analyses on observational data and results from a simple linear model and atmospheric general circulation model (AGCM) simulations. The mechanism is summarized as follows: the easterly phase of the QBO is accompanied with colder temperature in the 20 tropical tropopause layer, which enhances convective activity over the tropical western Pacific and suppresses over the Indian Ocean, thus enhancing the Walker circulation. -
Modulation of ENSO Teleconnection on the Relationship Between Arctic Oscillation and Wintertime Temperature Variation in South Korea
atmosphere Article Modulation of ENSO Teleconnection on the Relationship between Arctic Oscillation and Wintertime Temperature Variation in South Korea Sung-Ho Woo, Jahyun Choi and Jee-Hoon Jeong * Department of Oceanography, Chonnam National University, Gwang-ju 61186, Korea; [email protected] (S.-H.W.); [email protected] (J.C.) * Correspondence: [email protected]; Tel.: +82-62-530-3466 Received: 25 July 2020; Accepted: 4 September 2020; Published: 6 September 2020 Abstract: Despite progressing global warming, extreme cold events in East Asia are still occurring frequently with temperature variability enhanced. To understand this situation, it is necessary to determine external and internal climatic factors and their modulation effects that influence regional temperature variability. We found that the positive correlation between Arctic Oscillation (AO) and surface air temperature (SAT) in South Korea during winter is modulated strongly by tropical influences associated with El Niño Southern Oscillation (ENSO). In the case of a negative (positive) SAT anomaly in South Korea during the positive (negative) AO phase, a state that is opposite to the typical relationship between AO and SAT, the tropical sea surface temperature shows a typical negative (positive) ENSO-like pattern. The atmospheric teleconnection associated with the negative (positive) ENSO conditions contributes to a deepening (flattening) of the climatological East Asian trough and an enhancing (weakening) of the East Asian jet, which leads to negative (positive) SAT anomalies in South Korea. This modulation effect is robustly observed in the historical simulations of three different models of CMIP5. Keywords: El Niño southern oscillation; Arctic Oscillation; wintertime temperature; East Asia; teleconnection; East Asian jet 1. -
Moore, Oklahoma—Growth Cushions Tornado Impact
Cover Story Moore, Oklahoma—Growth COVER STORY Cushions Tornado Impact By Sandra Patterson photo courtesy City of Moore Economic Development Department oore, Oklahoma, is a city on the fast track of growth. Straddling I-35 and just 10 miles from Mdowntown Oklahoma City and 8 miles from Norman, home of the University of Oklahoma, Moore is a bedroom community experiencing an unprecedented surge in new home construction and an accompanying growth in retail development. According to Moore’s Economic Development Author- ity, more than 826 new home permits were issued in 2005 and commercial construction was valued at more than $16 million. The commission reports that the town’s assessed valuation has increased an average of 10 percent per year since 2001 to over $200 million in 2005. With a population of 18,781 in 1970, the city had grown to 41,138 by the 2000 census. It is expected to top 49,000 in 2006. Moore is also located in that part of the country known as Tornado Alley. And, of all the tornado-prone areas that comprise Tornado Alley, Moore is situated in one of Figure 1. Path of 1998 tornado (Map from National Weather Service the two that experiences the highest tornado count per Web site) square mile. Six Years, Three Tornadoes Since 1998, three tornadoes have torn through Moore. On October 4, 1998, a tornado struck the southwest side of the city (figure 1). With only F1 strength (see page 9 sidebar on the Fujita Scale), the damage was limited to ripped up vegetation, downed property fences, and torn roof shingles. -
A Climatology and Comparison of Parameters for Significant Tornado
106 WEATHER AND FORECASTING VOLUME 27 A Climatology and Comparison of Parameters for Significant Tornado Events in the United States JEREMY S. GRAMS AND RICHARD L. THOMPSON NOAA/NWS/Storm Prediction Center, Norman, Oklahoma DARREN V. SNIVELY Department of Geography, Ohio University, Athens, Ohio JAYSON A. PRENTICE Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa GINA M. HODGES AND LARISSA J. REAMES School of Meteorology, University of Oklahoma, Norman, Oklahoma (Manuscript received 18 January 2011, in final form 30 August 2011) ABSTRACT A sample of 448 significant tornado events was collected, representing a population of 1072 individual tornadoes across the contiguous United States from 2000 to 2008. Classification of convective mode was assessed from radar mosaics for each event with the majority classified as discrete cells compared to quasi- linear convective systems and clusters. These events were further stratified by season and region and com- pared with a null-tornado database of 911 significant hail and wind events that occurred without nearby tornadoes. These comparisons involved 1) environmental variables that have been used through the past 25– 50 yr as part of the approach to tornado forecasting, 2) recent sounding-based parameter evaluations, and 3) convective mode. The results show that composite and kinematic parameters (whether at standard pressure levels or sounding derived), along with convective mode, provide greater discrimination than thermodynamic parameters between significant tornado versus either significant hail or wind events that occurred in the absence of nearby tornadoes. 1. Introduction severe thunderstorms and tornadoes (e.g., Bluestein 1999; Davies-Jones et al. 2001; Wilhelmson and Wicker Severe weather forecasting has evolved considerably 2001). -
New Methods in Tornado Climatology
Geography Compass 9/4 (2015): 157–168, 10.1111/gec3.12205 New Methods in Tornado Climatology Holly M. Widen*, Tyler Fricker and James B. Elsner Florida State University Abstract How climate change might affect tornadoes remains an open scientific question. Climatological studies are often contested due to inconsistencies in the available data. Statistical methods are used to overcome some of the data limitations. A few of these methods including using the proportion of tornadoes occur- ring on big tornado days, estimating tornado energy from the damage path, and modeling counts spatially are described here. The methods move beyond analyses of occurrences by damage ratings and spatial smoothing. Applications of these and related methods will help grow the nascent field of tornado climatology. 1. Introduction Climate change and the recent high-impact tornado events have bolstered interest in the field of tornado climatology (Agee and Childs, 2014; Dixon et al., 2011; Farney and Dixon, 2014; Simmons and Sutter, 2012; Standohar-Alfano and van de Lindt, 2014). There is much to learn about how tornadoes might collectively change as the earth continues to warm. For example, new research shows more tornadoes on fewer days (Brooks et al., 2014; Elsner et al., 2014a), perhaps related to the combination of addi- tional moisture and warming aloft (Elsner et al., 2014a). Yet there is greater uncertainty surrounding the interpretation of such results owing to the nature of the dataset (Kunkel et al., 2013). Methods are needed to model the data that allow more confident physical interpretations. The Storm Prediction Center (SPC) contains the most readily available tornado database in the world. -
Twisters in Two Cities: Stuctural Ritualization
TWISTERS IN TWO CITIES: STUCTURAL RITUALIZATION THEORY AND DISASTERS By KEVIN M. JOHNSON Bachelor of Arts in Psychology Northeastern State University Tahlequah, Oklahoma 2011 Master of Science in Sociology Oklahoma State University Stillwater, Oklahoma 2013 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY May, 2019 TWISTERS IN TWO CITIES: STRUCTURAL RITUALIZATION THEORY AND DISASTERS Dissertation Approved: Dr. Duane A. Gill Dissertation Adviser Dr. J. David Knottnerus Dr. Monica Whitham Dr. Alex Greer ii ACKNOWLEDGEMENTS I would first like to thank my committee members – Dr. Duane Gill, Dr. J. David Knottnerus, Dr. Monica Whitham, and Dr. Alex Greer – for their insight and support throughout the writing of this dissertation. I am particularly grateful for Dr. Gill and Dr. Knottnerus, who have invested tremendous time and energy in mentoring and helping me develop as a sociologist and a thinker. I have had the privilege of working with some of my academic heroes on this project, and feel very fortunate to be able to make that claim. I would also like to thank my fellow graduate colleagues, Dr. Dakota Raynes, Christine Thomas, and many others, who were always willing to discuss various issues related to this research and countless other topics when needed. Your contributions to this work extend beyond the words on the page – thank you! Finally, I would like to acknowledge my family for their unwavering support and confidence in me throughout this process. Kasey, Gabriel, Ewok, and Leia: you have been my foundation, particularly in the toughest times, and I hope you all feel the joy of this accomplishment because it could not have happened without you. -
Article a Climatological Perspective on the 2011 Alabama Tornado
Chaney, P. L., J. Herbert, and A. Curtis, 2013: A climatological perspective on the 2011 Alabama tornado outbreak. J. Operational Meteor., 1 (3), 1925, doi: http://dx.doi.org/10.15191/nwajom.2013.0103. Journal of Operational Meteorology Article A Climatological Perspective on the 2011 Alabama Tornado Outbreak PHILIP L. CHANEY Auburn University, Auburn, Alabama JONATHAN HERBERT and AMY CURTIS Jacksonville State University, Jacksonville, Alabama (Manuscript received 23 January 2012; in final form 17 September 2012) ABSTRACT This paper presents a comparison of the recent 27 April 2011 tornado outbreak with a tornado climatology for the state of Alabama. The climatology for Alabama is based on tornadoes that affected the state during the 19812010 period. A county-level risk index is produced from this climatology. Tornado tracks from the 2011 outbreak are mapped and compared with the climatology and risk index. There were 62 tornadoes in Alabama on 27 April 2011, including many long-track and intense tornadoes. The event resulted in 248 deaths in the state. The 2011 outbreak is also compared with the April 1974 tornado outbreak in Alabama. 1. Introduction population density (Gagan et al. 2010; Dixon et al. 2011). Tornadoes have been documented in every state in Alabama is affected in the spring and fall by the United States and on every continent except midlatitude cyclones, often associated with severe Antarctica. The United States has by far the most weather and tornadoes. During summer and fall tornado reports annually of any country, averaging tornadoes also can be produced by tropical cyclones. A about 1,300 yr-1. -
Samantha Santeiu 02-15-09 Sec. 9, Dave Defina Chasing a Storm
Samantha Santeiu 02-15-09 Sec. 9, Dave DeFina Chasing a Storm Specific Purpose Statement : To inform my audience how meteorologists chase storms and about the importance of storm chasing in meteorological research. Central Idea : Storm chasing requires special tools and software; chases follow a general procedure on the chase day; and chasing has great importance in meteorological research. Pattern of Organization : topical. INTRODUCTION It’s September, 1900, in Galveston, Texas. Isaac Cline, a well-known climatologist, rides his horse and buggy along the beach. He’s here to observe the unusually high, gusting winds and huge waves crashing onshore. He orders the people of Galveston to evacuate. [VISUAL AID] Little did he know, he had just chased the massive Galveston hurricane of 1900 that would proceed to kill at least 6,000 people in the area. According to “A Brief History of Storm Chasing” on the National Association of Storm Chasers and Spotters website, this is one of the first accounts of storm chasing that we have. How about this: how many of you have seen the movie Twister ? [VISUAL AID] The basic storyline is that two people are storm chasers, and in the end they chase an epically huge tornado in the name of research. That is a more modern, albeit a bit inaccurate, account of storm chasing. I would like to inform you today about chasing storms, the way meteorologists do it. I plan to research severe storms as a career, so I have investigated the topic thoroughly and interviewed peers and professors on the subject. While storm chasing may seem like fun, there’s actually a lot involved. -
Withstanding the Winds Resilience Science
Level Two or Three 4-H Science, Engineering and Technology Project Activity Guide Withstanding the Winds Resilience Science Effects of High Wind High-wind events can form slowly offshore or very rapidly over land. In most cases, there is not enough time to protect your home before a storm strikes. This is why construction should be adapted to withstand regional vulnerabilities. High - Wind Events and Hazards Hurricanes Tornadoes Cat. 1: 74-95 mph EF0: 65-85 mph Cat. 2: 96-110 mph EF1: 86-110 mph Cat. 3: 111-129 mph EF2: 111-135 mph Level: Cat. 4: 130-156 mph EF3: 136-165 mph Two or Three Cat. 5: 157 or higher EF4: 166-200 mph EF5: 200 or higher Life skills: Decision making Thunderstorms Wind-Driven Hail Problem solving Responsibility Awareness Goal: Educate young people about wind -resistant construction and mitigation Along with rain and lightning, Hail is a common result of winds produced during tornadoes and/or thunderstorms. Authors: thunderstorms can range from 30 It can range from the size of a Shandy Heil mph to 100 mph. marble to a softball. Damage Identification Hurricane-force winds, tornadoes and hail produce different types of damage to buildings. Read the storm damage clues below and draw a line to the picture that shows the appropriate type of damage. Hurricane High-wind damage can blow off wall siding and shingles, produce wind-borne debris capable of breaking windows and, in some cases, cause structural damage to the walls and roof. Hail Damage includes broken windows and dents or punctures in wall siding and shingles. -
Riding the Storm
physicsworld.com Careers Riding the storm out A career in severe-weather research offers flexibility and plenty of opportunities to experience the fascinating physics of the rotating fluid called the atmosphere. Josh Wurman describes the science of storm-chasing and why hurricanes are scarier than tornadoes Take me to the weather Josh Wurman enjoys the freedom that being a freelance meteorologist affords him. I am standing on a bridge near the North thematical, essentially applied fluid dynam- mapped out the winds inside tornadoes, so Carolina coast. There is a light breeze, and I ics, and the real-world effects of these equa- no-one really knew how strong they were. am enjoying some hazy sunshine. But this tions can be seen every day. The equations After reading the relevant literature, I de- calm is an illusion: in a few minutes winds of of motion for the atmosphere cause trees to cided that a more ambitious technological up to 45 m s–1 (100 mph) will sweep in again. be blown down, hail to fall and snowdrifts and logistical approach could push back the The approaches to my section of the bridge to pile up – all things that I could witness veil of ignorance about these fascinating phe- are already drowned under 2.5 m of water, while growing up in Pennsylvania. nomena. So in 1994 I decided to shift focus, and my companions on this island are an I started out as a physics major at the Mas- leaving NCAR for a faculty position at the eclectic mix of traumatized animals, inclu- sachusetts Institute of Technology (MIT), University of Oklahoma, where I developed ding snakes, rats, wounded pelicans and but my real interest was meteorology, in a prototype mobile weather radar system frogs. -
Program At-A-Glance
Sunday, 29 September 2019 Dinner (6:30–8:00 PM) ___________________________________________________________________________________________________ Monday, 30 September 2019 Breakfast (7:00–8:00 AM) Session 1: Extratropical Cyclone Structure and Dynamics: Part I (8:00–10:00 AM) Chair: Michael Riemer Time Author(s) Title 8:00–8:40 Spengler 100th Anniversary of the Bergen School of Meteorology Paper Raveh-Rubin 8:40–9:00 Climatology and Dynamics of the Link Between Dry Intrusions and Cold Fronts and Catto Tochimoto 9:00–9:20 Structures of Extratropical Cyclones Developing in Pacific Storm Track and Niino 9:20–9:40 Sinclair and Dacre Poleward Moisture Transport by Extratropical Cyclones in the Southern Hemisphere 9:40–10:00 Discussion Break (10:00–10:30 AM) Session 2: Jet Dynamics and Diagnostics (10:30 AM–12:10 PM) Chair: Victoria Sinclair Time Author(s) Title Breeden 10:30–10:50 Evidence for Nonlinear Processes in Fostering a North Pacific Jet Retraction and Martin Finocchio How the Jet Stream Controls the Downstream Response to Recurving 10:50–11:10 and Doyle Tropical Cyclones: Insights from Idealized Simulations 11:10–11:30 Madsen and Martin Exploring Characteristic Intraseasonal Transitions of the Wintertime Pacific Jet Stream The Role of Subsidence during the Development of North American 11:30–11:50 Winters et al. Polar/Subtropical Jet Superpositions 11:50–12:10 Discussion Lunch (12:10–1:10 PM) Session 3: Rossby Waves (1:10–3:10 PM) Chair: Annika Oertel Time Author(s) Title Recurrent Synoptic-Scale Rossby Wave Patterns and Their Effect on the Persistence of 1:10–1:30 Röthlisberger et al. -
Reducing Tornado Fatalities Outside Traditional “Tornado
Reducing Tornado Fatalities Outside Traditional “Tornado Alley” Erin A. Thead May 2016 Introduction Atmospheric scientists have long suspected that climate change produces an increase in weather extremes of all varieties, but tornadoes are an unusually tricky case. A recent publication from the National Academy of Sciences summarizes the state of the art in the new discipline of event attribution, finding that that, although tornadoes are among the most difficult extreme weather events attribute to anthropogenic climate change, improvements in modeling and climate-weather model coupling have made possible some degree of probabilistic attribution.1 At present it seems likely that the influence of climate change on tornadoes is indirect, manifested largely by more direct influences on natural climate cycles such as the amplitude of waves in the jet stream that bounds the polar vortex and the El Niño-Southern Oscillation (ENSO), with which severe tornado seasons and their predominant locations have been loosely linked.2,3 Researchers are not yet in a position to say for sure what if any role climate change has played in the increases in tornado frequency and severity we have seen over the past 50 years.4 However, we need not wait until these issues are sorted out to begin working to protect vulnerable populations. In what follows, I first give some background on the increasingly significant threat posed by tornadoes and then outline some proactive steps governments and other entities can take to keep people safe. A Disturbing Trend A disturbing trend has already developed concerning tornado fatalities. After several decades of decline that can largely be credited to a great increase in forecasting skills and warning lead time, the United States fatality rate for tornadoes has leveled off, although there may have been a slight increase in recent years.