Air Masses

1
Air Masses

• Introduction
• Systems
• Earths Atmosphere
• Energy and Earth-Sun Relationships
• Energy Balance
• Temperature
• Pressure and Wind
• Atmospheric Circulation
• Moisture
• Lifting and Stability
• Clouds and Precipitation
• Air Masses ?
• Midlatitude Cyclones
• Thunderstorms
• Tropical Storms
• Forecasting

• Introduction
• Properties and Classification
• What factors are used for classification?
• Where do air masses form?
• What are the general characteristics of each air
  mass?
• Which air masses affect Wisconsin and why type of
  weather do they bring?

http//www.nasa.gov/vision/earth/everydaylife/clim
ate_class.html
2
Summary

• Sun Angle and Duration (latitude)
• Insolation and Net Radiation
• Heat and Temperature
• Land and Water (etc)
• Pressure and Wind (currents)
• Moisture
• Lifting and Stability

3
Air Mass Source Areas
http//www.uwsp.edu/geo/faculty/ritter/maps/air_ma
sses_2.jpg
4
Air Mass Table
5
Air Masses
2
4
1
3
6
7
5
6
Air Mass Modification

• How and why do cool air masses change as they
  move?
• How and why do warm air masses change as they
  move?
• How and why do wet air masses change as they
  move?
• How and why do dry air masses change as they move?

7
Effect of Polar Air Mass I
Aguado and Burt. Understanding Weather and Climate
8
Effect of Polar Air Mass II
Aguado and Burt. Understanding Weather and Climate
9
Effect of Polar Air Mass III
Aguado and Burt. Understanding Weather and Climate
10
Influence of mT Air Mass
RW Christopherson. Geosystems 4ed. Figure 8-3
11
Lake Effect Snow
RW Christopherson. Geosystems 4ed. Figure 8-4
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North American Winter Air Mass Patterns
RW Christopherson. Geosystems 4ed. Figure 8-2
13
North American Winter Air Mass Patterns
RW Christopherson. Geosystems 4ed. Figure 8-2
14
North American Summer Air Mass Patterns
15
North American Summer Air Mass Patterns
16
Review

• What is an air mass, and why do they form?
• How do we use latitude and type of surface to
  classify air masses?
• How does latitudinal position determine the
  relative temperature of an air mass?
• How does forming over land or water determine the
  specific humidity of an air mass?
• What are the 7 major air mass types, where do
  they form and how do they differ?
• How and why do air masses change as they move?
• What is the lake effect and how does it depend
  upon changes in an air mass?
• What air masses affect the US during summer and
  what are their characteristics?
• What air masses affect the US during winter and
  what are their characteristics?