Jenni L. Evans | |
|---|---|
 | |
| Alma mater | Monash University |
| Scientific career | |
| Institutions | Pennsylvania State University CSIRO Oceans and Atmosphere |
Jenni L. Evans is a Professor of Meteorology and Atmospheric Science at Pennsylvania State University, Director of the Institute for CyberScience and President of the American Meteorological Society. She was elected a Fellow of the American Meteorological Society in 2010 and the American Association for the Advancement of Science in 2019.
Evans studied applied mathematics at Monash University and graduated with honours in 1984. [1] [2] Prior to her PhD, she worked on fluid dynamics and observations of the planetary boundary layer. During her PhD, Evans visited the Naval Postgraduate School in Monterey, California and the supercomputing group at NASA Ames in 1987 and 1988. She returned to Monash for her doctoral studies and earned her PhD in 1990, then joined CSIRO Oceans and Atmosphere. [1]
In 1992 Evans joined Pennsylvania State University. [1] She earned tenure in 1998 and was promoted to Professor in 2005. [3] In 2017 she was appointed Director of the Institute of CyberScience. Her research considers the genesis and decay of tropical cyclones, including the extratropical transition and landfall. [4] She has investigated the impact of climate change on tropical cyclones. [5] She has developed statistical methodologies for forecasts of tropical cyclones and a metric to for cyclogenesis activity in climate change situations. [5] Evans has looked at the relationships between tropical cyclone intensity and organised convection with sea surface temperature, and how these will change with global warming. She has considered how the tropical cyclone boundary layer structures impact the intensity and impacts of convection on the development of African easterly jets. Evans co-chaired the World Meteorological Organization International Workshop on Tropical Cyclones. [6]
Evans has described hurricanes as one of the last remaining weather systems that cannot be predicted. [7] Evans is a member of an interdisciplinary team charged with reviewing catastrophic risk models used for setting hurricane insurance rates in Florida. [6] Alongside her observations, modeling and statistical analysis of meteorological phenomena, Evans develops new approaches to communicate the risk of natural disasters. She has worked with Mark Ballora on new ways to demonstrate the risks of hurricanes. [8] Evans contributed her expertise in natural disasters and Ballora his background in music, and together they convert data that is typically in charts or graphs into music. [8] Evans monitored the latitude, longitude, asymmetry and air pressure of several hurricanes and convert this into an audio file. [8] Evans has served as Lead Meteorologist advising the Florida Commission on Hurricane Loss Projection Methodology. [9]
In 2019 Evans participated in a National Science Foundation grant to establish the Northeast Big Data Innovation Hub. [10]
Whilst serving on the United States Army Science Team Evans was involved with the relocation of their tropical test facility to Panama. Evans was elected President of American Meteorological Society (AMS) in 2019, which was the 100th year of the AMS.
Her awards and honours include;
Her publications include;
Evans has written for The Conversation. [14]
In meteorology, a cyclone is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above. Cyclones are characterized by inward-spiraling winds that rotate about a zone of low pressure. The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale. Mesocyclones, tornadoes, and dust devils lie within the smaller mesoscale. Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the tropical upper tropospheric trough during the summer months in the Northern Hemisphere. Cyclones have also been seen on extraterrestrial planets, such as Mars, Jupiter, and Neptune. Cyclogenesis is the process of cyclone formation and intensification. Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones. These zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their life cycle, extratropical cyclones occlude as cold air masses undercut the warmer air and become cold core systems. A cyclone's track is guided over the course of its 2 to 6 day life cycle by the steering flow of the subtropical jet stream.
A subtropical cyclone is a weather system that has some characteristics of both tropical and an extratropical cyclone.
The Carl-Gustaf Rossby Research Medal is the highest award for atmospheric science of the American Meteorological Society. It is presented to individual scientists, who receive a medal. Named in honor of meteorology and oceanography pioneer Carl-Gustaf Rossby, who was also its second (1953) recipient.
A tropical wave, in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which moves from east to west across the tropics, causing areas of cloudiness and thunderstorms. Tropical waves form in the easterly flow along the equatorial side of the subtropical ridge or belt of high air pressure which lies north and south of the Intertropical Convergence Zone (ITCZ). Tropical waves are generally carried westward by the prevailing easterly winds along the tropics and subtropics near the equator. They can lead to the formation of tropical cyclones in the north Atlantic and northeastern Pacific basins. A tropical wave study is aided by Hovmöller diagrams, a graph of meteorological data.
William "Bill" Mason Gray was emeritus professor of atmospheric science at Colorado State University (CSU), and the head of the Tropical Meteorology Project at CSU's Department of Atmospheric Sciences. He is widely regarded as a pioneer in the science of tropical cyclone forecasting and one of the world's leading experts on tropical storms. After retiring as a faculty member at CSU in 2005, Gray remained actively involved in both climate change and tropical cyclone research until his death.
This is a list of meteorology topics. The terms relate to meteorology, the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting.
Kerry Andrew Emanuel is an American professor of meteorology currently working at the Massachusetts Institute of Technology in Cambridge. In particular he has specialized in atmospheric convection and the mechanisms acting to intensify hurricanes.
A mesoscale convective system (MCS) is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical cyclones, and normally persists for several hours or more. A mesoscale convective system's overall cloud and precipitation pattern may be round or linear in shape, and include weather systems such as tropical cyclones, squall lines, lake-effect snow events, polar lows, and mesoscale convective complexes (MCCs), and generally forms near weather fronts. The type that forms during the warm season over land has been noted across North and South America, Europe, and Asia, with a maximum in activity noted during the late afternoon and evening hours.
A hot tower is a tropical cumulonimbus cloud that reaches out of the lowest layer of the atmosphere, the troposphere, and into the stratosphere. These formations are called "hot" because of the large amount of latent heat released as water vapor condenses into liquid and freezes into ice within the cloud. Hot towers in regions of sufficient vorticity may acquire rotating updrafts; these are known as vortical hot towers In some instances, hot towers appear to develop characteristics of a supercell, with deep and persistent rotation present in the updraft. The role of hot towers in tropical weather was first formulated by Joanne Simpson in 1958. Hot towers dominated discussions in tropical meteorology in the 1960s and are now considered the main drivers of rising air within tropical cyclones and a major component of the Hadley circulation. Although the prevalence of hot towers in scientific literature decreased in the 1970s, hot towers remain an active area of research. The presence of hot towers in tropical cyclones is correlated with an increase in the tropical cyclones's intensities.
The eye is a region of mostly calm weather at the center of a tropical cyclone. The eye of a storm is a roughly circular area, typically 30–65 kilometers in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather and highest winds of the cyclone occur. The cyclone's lowest barometric pressure occurs in the eye and can be as much as 15 percent lower than the pressure outside the storm.
The central dense overcast, or CDO, of a tropical cyclone or strong subtropical cyclone is the large central area of thunderstorms surrounding its circulation center, caused by the formation of its eyewall. It can be round, angular, oval, or irregular in shape. This feature shows up in tropical cyclones of tropical storm or hurricane strength. How far the center is embedded within the CDO, and the temperature difference between the cloud tops within the CDO and the cyclone's eye, can help determine a tropical cyclone's intensity with the Dvorak technique. Locating the center within the CDO can be a problem with strong tropical storms and minimal hurricanes as its location can be obscured by the CDO's high cloud canopy. This center location problem can be resolved through the use of microwave satellite imagery.
Tropical cyclogenesis is the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropical cyclogenesis occurs are distinctly different from those through which temperate cyclogenesis occurs. Tropical cyclogenesis involves the development of a warm-core cyclone, due to significant convection in a favorable atmospheric environment.
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of producing anything from cloudiness and mild showers to severe gales, thunderstorms, blizzards, and tornadoes. These types of cyclones are defined as large scale (synoptic) low pressure weather systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, extratropical cyclones produce rapid changes in temperature and dew point along broad lines, called weather fronts, about the center of the cyclone.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, or simply cyclone. A hurricane is a strong tropical cyclone that occurs in the Atlantic Ocean or northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean. In the Indian Ocean, South Pacific, or (rarely) South Atlantic, comparable storms are referred to as "tropical cyclones", and such storms in the Indian Ocean can also be called "severe cyclonic storms".
Thomas R. Knutson is a climate modeller at the US Geophysical Fluid Dynamics Laboratory, a division of the National Oceanic and Atmospheric Administration (NOAA). His research covers hurricane activity, the link between climate change and hurricane incidence and intensity, and climate change detection and attribution.
In meteorology, eyewall replacement cycles, also called concentric eyewall cycles, naturally occur in intense tropical cyclones, generally with winds greater than 185 km/h (115 mph), or major hurricanes. When tropical cyclones reach this intensity, and the eyewall contracts or is already small, some of the outer rainbands may strengthen and organize into a ring of thunderstorms—a new, outer eyewall—that slowly moves inward and robs the original, inner eyewall of its needed moisture and angular momentum. Since the strongest winds are in a tropical cyclone's eyewall, the storm usually weakens during this phase, as the inner wall is "choked" by the outer wall. Eventually the outer eyewall replaces the inner one completely, and the storm may re-intensify.
A cold-core low, also known as an upper level low or cold-core cyclone, is a cyclone aloft which has an associated cold pool of air residing at high altitude within the Earth's troposphere, without a frontal structure. It is a low pressure system that strengthens with height in accordance with the thermal wind relationship. If a weak surface circulation forms in response to such a feature at subtropical latitudes of the eastern north Pacific or north Indian oceans, it is called a subtropical cyclone. Cloud cover and rainfall mainly occurs with these systems during the day.
The 1951 Pacific hurricane season ran through the summer and fall of 1951. Nine tropical systems were observed during the season.
Hurricane Alex was the first Atlantic hurricane to occur in January since Hurricane Alice of 1954–55. Alex originated as a non-tropical low near the Bahamas on January 7, 2016. Initially traveling northeast, the system passed by Bermuda on January 8 before turning southeast and deepening. It briefly acquired hurricane-force winds by January 10, then weakened slightly before curving towards the east and later northeast. Acquiring more tropical weather characteristics over time, the system transitioned into a subtropical cyclone well south of the Azores on January 12, becoming the first North Atlantic tropical or subtropical cyclone in January since Tropical Storm Zeta of 2005–2006. Alex continued to develop tropical features while turning north-northeast, and transitioned into a fully tropical cyclone on January 14. The cyclone peaked in strength as a Category 1 hurricane on the Saffir–Simpson scale (SSHWS), with maximum sustained winds of 85 mph and a central pressure of 981 mbar. Alex weakened to a high-end tropical storm before making landfall on Terceira Island on January 15. By that time, the storm was losing its tropical characteristics; it fully transitioned back into a non-tropical cyclone several hours after moving away from the Azores. Alex ultimately merged with another cyclone over the Labrador Sea on January 17.
Sukyoung Lee is a professor at Pennsylvania State University known for her research on circulation in Earth's atmosphere and the Southern Ocean. In 2021 Lee was elected a fellow of the American Geophysical Union.
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