SCI 100 - Meteorology: Chapter 7 Focus
Questions and Topics to Study
Describe the various scales of motion in terms of horizontal extent and life span. Give examples of
microscale and mesoscale events discussed in lecture.
What is wind shear and how does it relate to clear air turbulence (CAT)?
Explain what causes a sea breeze and its differences from a land breeze.
Ch 7 Focus, page 1 of 4
Chapter 7 Questions and Topics to Study (cont’d)
Know the definition of the monsoon wind system.
Briefly explain how the monsoon wind system develops over eastern and southern Asia.
Why, in India, is the summer monsoon wet and the winter monsoon dry?
Which of the following will produce clouds: a valley breeze or a mountain breeze? Why?
What are katabatic winds and how do they form?
Explain why Chinook winds are warm and dry.
Ch 7 Focus, page 2 of 4
Chapter 7 Questions and Topics to Study (cont’d)
What are Santa Ana winds and why are they dangerous?
Provide a detailed explanation as to why the West Coast of the U.S. receives much less precipitation
than the East Coast of the U.S. during the Summer.
Define the Jet Stream?
Know the main aspects of/differences between the Polar Frontal Jet (PFJ and the Subtropical Jet (STJ).
What are the key aspects of a strong El Nińo event?
Know the importance of these Real-World Pressure Systems:
Bermuda High
Thermal Low
Pacific High
Siberian High
Ch 7 Focus, page 3 of 4
SCI 100L Handout: Features of the 3-Cell Global Circulation Model
Three-Cell Model: General Circulation of the Atmosphere
Know what they are, where they are located, what causes them (Figure 7.25, page 203)
Intertropical Convergence Zone (ITCZ)
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Zone within the tropics where there is convergence of the Trade Winds
Area of lower surface pressure within the Tropics (due to excess heating and rising air)
Lots of rising air thus cloudy and rainy conditions are generally associated with it
Hadley Cell (named for George Hadley, an 18th century English meteorologist)
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Thermally-driven, large-scale vertical circulation (convection) loop
Warm air rises near the thermal equator, moves poleward, piles up and sinks around 30°N/S
The loop is completed at the surface as winds spiral out of the Subtropical Highs and move towards
the equator, thus forming the Trade Winds
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Shallow, surface high pressure areas in the polar regions due to cold, dense air
o Polar highs are cold (due to much less insolation received) and are dry (little water vapor)
They generate winds known as the Polar Easterlies; Lots of sinking air at their centers
Real-world examples are the Siberian High (in Northeast Russia) and the Canadian High
Polar Highs
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Polar Front (Note: a “front” is a boundary between two unlike features)
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Zone of conflicting surface winds near 50-60° latitude of both hemispheres where low pressure
systems (mid-latitude cyclones) tend to develop
o Caused by the Prevailing Westerlies interacting with the Polar Easterlies
Also known as a zone of conflict (or transition) between warm, moist Subtropical High (mT air
mass) and cold, dry Polar High (cP air mass)
Subtropical Highs (STHs)
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Belt of surface high pressure within the subtropical region (25-30° N/S)
Form on the poleward-side of the Hadley Cell as air piles up and adds mass to the region
Air sinks and warms adiabatically within their centers thus fair weather with little rain prevail
 Real-world examples are the Pacific High and the Bermuda High
Trade Winds (Northeast Trades ; Southeast Trades)
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Fairly steady surface winds that blow from the east within the tropical region
They form as air spirals out of the Subtropical High and moves towards the equator
They help form the ITCZ and help move tropical weather systems from East to West
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Winds that blow from the west within the mid-latitudes
They form as air spirals out of the Subtropical High and moves towards the poles
They help drive mid-latitude weather systems towards the east (generally from west-to-east)
Westerlies (aka, Prevailing Westerlies)
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