Final Exam Study Guide1. Understand the difference between a “hurricane” and a “typhoon”- Hurricanes: Atlantic Ocean, North Pacific east of the dateline- Typhoons: North Pacific west of the dateline2. What are the ingredients for hurricane formation? Why don’t hurricanes typically form within 5 degrees latitude of the equator?- Warm sea-surface temperature (greater than 26*C/79*F)- Moisture at low levels in the atmosphere- Light winds throughout the troposphere- Most form within 20* of the equator (but not right on the equator): There is no Coriolis Force rightat the equator3. What are the parts of a hurricane?- Eye: The cyclone’s center. Relatively calm, clear area usually 20-40 miles across. - Eyewall: Storm is the strongest. The dense wall of thunderstorms surrounding the eye has thestrongest winds within the storm. - Rainbands: Spiral, dense bands of thunderstorms.4. What are the stages of development of a hurricane, from “tropical depression” to full-fledged “hurricane” (you don’t need to know exact wind speeds, but you should be able to describe what happens at each stage)1. Tropical Wave/Disturbance: birth of a hurricane, having slight circulation with no closed isobarsaround an area of low pressure. Commonly exist in the tropical trade winds and accompanied byclouds and rain.2. Tropical Depression: at least one closed isobar that accompanies a drop in pressure in the center ofthe storm3. Tropical Storm: intensified circulation, begin to see an eye wall in development as well as a near-definite center of circulation, the eye.4. Hurricane: pronounced rotation develops around the center core as spiral rain bands rotate aroundthe eye of the storm. Heaviest rain and strongest winds are associated with the eye wall.5. Know the minimum wind speed necessary for a storm to be considered a hurricaneSustained wind speeds exceed 64 knots (74 mph)6. What are the characteristics of a “typical” hurricane?- 300 miles across- Central pressure about 50-60 mb lower than outside air- Sustained wind speed of about 100-150 mph- Forward speed around 15-20 mph- Lifetime of about 10 days7. What are the hazards associated with hurricanes? Be able to give a definition of ‘storm surge’ and explain how it forms- High winds: even the weakest cyclone winds can cause damage to poorly constructed orunprepared buildings- Tornadoes: occur in the right rear quadrant or embedded in the rainbands of a hurricane.- Flooding: at least 6-12 inches of rainfall. Rains are heaviest with slower moving storms (less than10 mph)- Storm surge: most deaths/destruction. Refers to water that is pushed towards the shore by theforce of the winds of the storm. It is an abnormal rise of water generated by a storm, over andabove the predicted astronomical tides.8. What is the scale that the United States uses to describe hurricane intensity?Hurricane intensity is ranked according to the Saffir-Simpson Scale based on 1-5. 3 and higher areconsidered major hurricanes.9. What causes a hurricane to die out?- It remains in the same area of ocean for too long, churning up the warm water, and bringing coldwater to the surface. Without warm water, the storm can’t survive.- It experiences wind shear, causing the convection to lose direction and the heat engine to breakdown - It can be weak enough to be consumed by another area of low pressure, disrupting it and joining tobecome a large area of non-cyclonic thunderstorms.- It enters colder waters. This does not necessarily mean the death of the storm, but the storm willlose its tropical characteristics. These storms are extratropical cyclones.- An outer eye wall forms (typically around 50 miles from the center of the storm), choking off theconvection toward the inner eye wall.- It moves over land such as mountains, thus depriving it of the warm water it needs to power itself,and quickly loses strength. Most strong storms become disorganized areas of low pressure within aday or two of landfall.10. How do we define “climate”?Climate is the pattern of weather that occurs in an area over many years. It determines the types ofplants or animals that can survive, and it influences how people live. Usually defined as the“average weather”, or more rigorously, as the statistical description in terms of the average andvariability of relevant quantities over a period of time ranging from months to thousands ormillions of years. The classical period to define climate is 30 years, as defined by the WorldMeteorological Organization (WMO)11. How is “climate change” different from “climate variability”?- Climate Change: In general, climate is said to be changing if there is a change in average annual parameters such as temperature and/or precipitation over a 30 year (or more) time period. A change in climate is typically brought about by a “forcing” to the system (more on this later)- Climate Variability: On the other hand, there are many short-term “perturbations” to the climate system (such as the El Niño/ Southern Oscillation) that temporarily (on the order of months to a fewyears), alter the climate of a region. This is referred to as “climate variability”.12. Be able to describe the various processes by which Earth’s climate can change (e.g. changes in solar radiation, etc.)External Factors:- Changes in solar radiation- Changes in Earth’s orbital parameters (“Milankovitch parameters”): The combination of these factors influence the amount of solar energy at high latitudes in the summer, which influence the growth or shrinkage of ice glaciers.o Orbital eccentricity: the shape of the orbit around the sun. Affects total amount of radiation Earth’s surface receives as well as the difference in energy received at aphelion and perihelion.o Axial tilt: varies between 21.5-24.5 degrees in a periodic manner. Changes in the tilt cause large changes in the seasonal distribution of radiation at high latitudes and in the length of the winter dark period at the poles. Very little effect on low latitudes.o Direction of tilt in space: Precession of the equinoxes is the change in the direction of the Earth’s axis of rotation relative to the sun at the time of perihelion and aphelion. Affects which hemisphere is tilted towards the sun and which hemisphere is tilted away from the sun.- Impacts by meteors/ asteroids: throws dust into the sky, darkening the planet and cause