Review outline for Exam #2

Clouds

n What are clouds? How do they usually form?

n What are cloud condensation nuclei?

n Why do clouds most often form well above the ground surface?

n Lifting and lowering parcels of air in the atmosphere (Homework #4)

n Determine altitude where clouds expected to form

Precipitation

n Difference between cloud droplets and rain drops

n In the Bergeron process, what grows and what shrinks (don’t need to understand why)? Have cloud seeding programs been successful?

n What happens to falling raindrops or snowflakes? What is virga?

n Difference between freezing rain and sleet

Ways to get air to rise

n Convection (thermals)

n Mountains

n Rain shadow and explanation

n Surface convergence and upper-level divergence

n Relationship between 500 mb pattern, horizontal divergence above 500 mb, and rising motion in the atmosphere.

n Relationship between surface low pressure areas, horizontal convergence, and rising motion in the atmosphere.

n Weather fronts

n What are fronts? Air masses? Which air mass rises?

Stability

n What is meant by an "unstable" atmosphere? List 3 changes which act to destabilize the atmosphere.

n General type of cloud expected in stable and unstable atmospheres

n What makes the atmosphere unstable? How is it that a rising parcel can become warmer than the surrounding atmosphere?

n Lifting parcels of air in the atmosphere. You will have to be able to keep track of the temperature and dew point temperature in rising parcels of air.

n Identify where clouds form

n Identify stable and unstable regions

Thunderstorms

n What is the main energy source for thunderstorm development?

n Life cycle of a single cell thunderstorm (know handout & diagrams)

n Frequency distribution of thunderstorms over the U. S. (Map on class web site under lecture notes) and explanation for major features

n Hail and microbursts

n What are lightning and thunder? (basic one sentence definitions)

n Briefly, what occurs in thunderstorms to set the stage for lightning?

n Distance to a lightning strike based on time between lightning and thunder

n Lightning safety and detection

Tornadoes

n What is wind shear? Why is it necessary for tornado formation? How are tornadoes thought to develop (handout)

n Frequency distribution for tornadoes over the U. S. (Map on class web site under lecture notes). Note differences depending on intensity of tornadoes.

n Which region of the world experiences the most tornadoes?

n Tornado characteristics and safety

Hurricanes

n Tropical cyclones (distinguish between tropical depression, tropical storm, and hurricane)

n Characteristic (typical) weather conditions in tropics. What are trade winds? What are tropical or easterly waves? Most of the major hurricanes that hit the US begin as tropical waves. What is it about tropical waves the can help to get hurricanes started?

n Hurricane tracks (figure on class web site under lectures)

n Where do hurricanes form and which way do they most often move?

n Know a bit about each of the 5 requirements for tropical storm development (no need to memorize the list)

n Intensification to hurricane strength (side view from in class notes)

n Main energy source

n Near center of storm - relatively low pressure at ocean surface and relatively high pressure near top of troposphere

n Horizontal wind flow at ocean surface and at top of troposphere

n Basic anatomy (top down view from in class notes) of a hurricane

n Eye, eye wall, spiral rain bands

n Most hurricane damage is caused by storm surge. What is the storm surge? What factors affect the severity of the storm surge?

Severe weather statistics for the U. S. for the decade of the 1990s

n Which events result in the most deaths? Least deaths? Most dollar damage?

n Why are dollar costs for many types of severe weather increasing (even after removing the effects of inflation)?

n It is not because the number of severe weather events is increasing or because severe events are more intense than they were in the past (with the exception of flash flooding, which has shown evidence for recent increases.)

n Make sure you pay particular attention to the problem of heat-related deaths. Read the NY Times article mentioned (with a web link on lecture page).

Seasons

n What are the two factors are responsible for seasonal changes in the amount of solar energy intercepted by the surface?

n Where on Earth are seasonal changes the largest between summer and winter? Where are they the smallest? And why?

n What is it about Earth’s orbit about the Sun that gives rise to seasonal changes in the distribution of solar energy around the globe?

n Just know that slight variations in Earth’s orbit about the Sun has been linked to climate changes. No specific questions about this material.

n Know the terms, solar angle, solar declination, summer solstice, winter solstice, spring equinox, fall equinox, tropics, arctic and Antarctic regions.

n Given the solar declination be able to compute the solar angle at noon for any given latitude. Understand how the solar angle at noon changes during the year at a given latitude, qualitatively not quantitatively.

n Qualitatively how does the length of day vary with time of year and latitude?

n How do the popular usages of the 4 seasons correspond to the dates of the solstices and equinoxes?

n Outside of the tropics, what is the relationship between the day of maximum solar heating and warmest temperatures? What is the relationship between the day of minimum solar heating and coldest temperatures?

Stratospheric Ozone

n Why is stratospheric ozone necessary for most life on the Earth’s surface?

n Which type of man-made chemicals is responsible for depleting the amount of ozone in the stratosphere?

n Up to this point, what have been the measured reductions in stratospheric O₃? How have these reductions impacted the citizens of the United States?

n What is the "ozone hole"? When and where does it occur?

n Has anything been done about the stratospheric ozone depletion problem?

Ultraviolet Radiation

n Where does ultraviolet (uv) radiation come from?

n How does the energy possessed by a uv photon compare to the energy possessed by visible and infrared photons? What is the relevance of the energy differences?

n Effects of uv radiation on the human body

n What is skin cancer and how is it caused by exposure to uv radiation?

n Ways the human body protects itself from skin cancer related to uv exposure

n "ABCD" self-examination

n UV Protection

n How do sunscreens work? What does SPF mean?

n Are you safe in the shade? On cloudy days?

n Relationship between uv exposure and …

n Sun Angle

n Air temperature

n Altitude

n Concentration of aerosol particles and humidity

n Why is Tucson a particularly dangerous place for UV exposure?

n UV Index