ATM OCN (Meteorology) 100

REVIEW QUESTIONS/STUDY GUIDE 
for 2nd EXAM (19 November 1999)
ATM OCN 100: WEATHER & CLIMATE

Fall 1999  Lecture 2

TOPICS COVERED FOR SECOND HOUR EXAM

WATER VAPOR

• HUMIDITY INSTRUMENTS
• Sling psychrometers, hair hygrometers, dewpoint hygrometers, hygristors.
• TYPES OF HUMIDITY VARIABLES
• Vapor pressure, dewpoint, wet-bulb.
• Apparent temperature/heat stress.
• SATURATION
• BOILING

• DISTINGUISHING FEATURES
• FORMATION PROCESSES
• Saturation Mechanisms
• Cooling Mechanisms
• ADDITIONAL REQUIREMENTS
• Cloud condensation nuclei
• Freezing nuclei
• CLOUD OBSERVATIONS & CLOUD CLASSIFICATION SCHEME
• FOG TYPES

• FORMATION THEORIES
• PRECIPITATION OBSERVATIONS & INSTRUMENTS
• PRECIPITATION TYPES (Liquid, frozen and freezing)
• DEFINITIONS
• ATMOSPHERIC CONDITIONS
• WEATHER MODIFICATION
• PRECIPITATION ENHANCEMENT and CLOUD DISPERSAL

• SCATTERING PHENOMENA - Blue Skies (Rayleigh) & White clouds (Mie)
• REFRACTION PHENOMENA - Mirages
• OPTICAL PHENOMENA ASSOCIATED WITH LIQUID WATER DROPS
• Rainbows
• Coronas & Glories
• OPTICAL PHENOMENA ASSOCIATED WITH ICE CRYSTALS
• Haloes, Sun Dogs & Sun Pillars

• WIND OBSERVATIONS & INSTRUMENTS
• EQUATION OF ATMOSPHERIC MOTION
• COMPONENTS
• SIMPLE MODELS: Hydrostatic Balance; Geostrophic, Gradient, & Friction-Layer Flow
• LINKAGE BETWEEN VERTICAL & HORIZONTAL FLOW
• EQUATION OF MASS CONTINUITY
• DINES' COMPENSATION
• LOCAL ATMOSPHERIC CIRCULATION REGIMES
• LAKE (SEA) - LAND BREEZE
• MOUNTAIN - VALLEY BREEZE
• UPPER AIR OBSERVATIONS & DISPLAY
• OBSERVATIONS, INSTRUMENTS & PLATFORMS
• UPPER AIR CHARTS
• GENERAL RELATIONSHIPS

Are you able to answer the following?

• What is atmospheric humidity, and how is this weather element measured?  Can you name three instruments used to measure atmospheric humidity?  What are typical ways in which atmospheric humidity is described? Give representative values for each.
• Define vapor pressure and saturation vapor pressure; mixing ratio and saturation mixing ratio, relative humidity, dewpoint and wet-bulb temperature. Why is the dewpoint the best indicator of the actual vapor content of the actual atmosphere? Why does the relative humidity undergo a diurnal variation, usually being higher at night than in mid-day, even though dewpoint may exhibit little change?
• What is apparent temperature (heat index) and why is it significant? What factors are needed to determine the apparent temperature? Given these factors, determine the apparent temperature from the provided table. What do your answers indicate about human comfort?
• Given an air parcel, what are the two ways needed to achieve saturation? What is meant by saturation? What is supersaturation?
• What is a saturation adiabatic process? What are the dry adiabatic and saturation adiabatic lapse rates and how are these process lapse rates used? Why does a difference exist between these two process lapse rates? Clearly understand the difference between the process lapse rates and the actual or environmental lapse rate. This distinction is fundamental!
• What is the LCL? What happens when air moves over mountain ranges? What is a chinook (or a foehn) and a Santa Ana?
• What are the three basic ingredients needed for cloud formation? Understand the mechanisms needed for the formation of clouds.
• What is fog? How does fog compare with clouds? What are the various fog types? How are these fogs formed? How are dew and frost typically formed?
• In what ways do the cumuliform and stratiform cloud formation mechanisms differ?
• What are the various cloud types? Can you name the 10 major cloud genera? What are some identifying characteristics of each, to include optical features (corona, halo)? Which clouds are considered warm clouds, with liquid water droplets? Which are cold clouds with ice crystals? Which cloud types typically produce the most precipitation?
• Given a cloud, what additional "ingredients" are usually necessary for precipitation formation, particularly in middle and higher latitudes? What factors hinder precipitation formation?
• Can you identify the three precipitation formation theories? What is the basic premise of each? Why is the simple diffusion-condensation process inefficient? What process or processes are important for explaining precipitation in tropical and in extratropical latitudes?
• What is meant by freezing nuclei? What is the difference between condensation and freezing nuclei?
• How is precipitation measured? What are the precautions used in measurement of precipitation?
• Can you distinguish between the types of precipitation? What are the atmospheric conditions associated with each precipitation type?
• What is done in attempts to stimulate artificially precipitation (two ways)? What atmospheric conditions are needed to stimulate significant precipitation?
• Do you know the differences between scattering, reflection, refraction, dispersion and diffraction?
• Why is the unpolluted sky blue, the clouds white and sunsets red?
• What produces a rainbow? Where in the sky and under what conditions would you most likely see a rainbow? How are rainbows formed? What are the color sequences of the primary and secondary rainbows? What meteorological significance is associated with rainbows?
• Distinguish between a halo and a corona. What cloud type(s) would produce each of  these phenomena? When and in what direction would you look for coronae and haloes? What meteorological significance is associated with these individual optical phenomena?
• What is a glory? What produces a glory? In what direction would you expect to find a glory?
• What is a mirage? How is it formed?
• How are the winds named?  Specifically, what is meant by a north wind? What is the Beaufort Scale?
• Do you know the difference between a vector and scalar quantity? Can you describe speed, velocity, acceleration, and force? Can you provide vector representations? Relate these vector quantities to Newton's Laws.
• What do Newton's Laws of Motion say (the first and second laws)?
• What is the equation of atmospheric motion? Thoroughly understand what the atmospheric equation of motion states.
• What are the forces that can cause an air parcel to accelerate? In which direction does each force act? Which force(s) causes the parcel to move and which forces affect only its directional motion?
• Why is the pressure gradient force divided into two components? Contrast the relative size of the horizontal pressure gradient force with the vertical pressure gradient force.
• What does hydrostatic equilibrium mean? Which two forces are involved in this relationship? If hydrostatic balance exists, will air that is rising continue to rise, stop rising, sink? Why?
• Know how to draw the horizontal pressure gradient force on surface weather maps analyzed at sea level with isobars, identifying the direction of this force and its relative magnitude.
• Understand the Coriolis effect. Why is it caused, what is its direction and what are the three factors affecting the magnitude of this effect?
• What is the geostrophic wind? What assumptions are made to obtain the geostrophic wind? What are the consequences of these assumptions? Name some situations where these assumptions are poor. Be sure you can draw the geostrophic wind vector for both hemispheres from a given pressure pattern. You should be able to identify the forces involved. What factors influence the strength of the geostrophic wind? How does the geostrophic wind vary with latitude for the same horizontal pressure gradient?
• How does the geostrophic wind blow in the Southern Hemisphere as compared to the Northern Hemisphere?
• Why does the wind blow across the isobars in the friction layers? Compare the frictional effects in each hemisphere. Why does the near-surface wind often die at sunset? (The atmosphere becomes more stable and the influence of friction is concentrated in a shallower layer of air than during mid day.)
• What is the orientation of the winds around a cyclone? an anticyclone? How does friction affect these flow patterns?
• What force relationship exists for the maintenance of the gradient wind around a cyclone? Around an anticyclone? Be able to draw all the force vectors responsible for gradient wind flow. Contrast the gradient wind flow around Northern Hemisphere cyclones and anticyclones with that around Southern Hemisphere cyclones and anticyclones.
• Above the friction layer, what causes the wind speed and direction to differ at different heights?
• Contrast the four scales of atmospheric circulation: planetary, synoptic, mesoscale and microscale. Give examples of each scale.
• What is a thermally direct circulation regime? a thermally indirect circulation regime? Given an example of each regime.
• What is meant by convergence and divergence?
• What is Dines Compensation and what are its implications? What conditions must occur for a surface low to deepen? To weaken? How do surface highs strengthen or weaken?
• Do you understand how differences in heating (or cooling) are needed to initiate air motion? In other words, what are the two ways in which horizontal pressure gradient forces develop? Which mechanism is most fundamental?

Can you explain how the sea (or lake) breeze develops? The land breeze? Why does water heat and cool more slowly than land? (List 4 reasons) Why does the sea breeze tend to blow parallel to the coastline near the onset of early evening?

Last revision 12 November 1999

URL: aos100/exams/f9rques2.htm