ATM OCN (Meteorology) 100

ATMOSPHERIC PRESSURE:
A FUNDAMENTAL WEATHER ELEMENT

Summer 2000

Lecture #2-B Scheduled for:

13 JUN 2000 (T)

Recommended Readings from Moran and Morgan (1997):

pages 109-120 (through 1st paragraph).

NOTE: This lecture is continued from Atmospheric Composition (Physical & Chemical)

Today's Lecture Objectives:

• To define and describe the concept of air pressure.
• To explain the meaning of pressure balance.
• To list the types of barometers.
• To describe the principles of the mercury and aneroid barometers, listing their respective advantages.
• To list typical values and the observed extreme ranges of surface barometric pressure.
• To describe why and how the pressure changes with increasing altitude in the earth's atmosphere, ranging from the earth's surface to a height of several hundred kilometers.
• To explain why station pressure readings are "reduced" to mean sea level.
• To explain the fundamental causes for the difference between surface high and low atmospheric pressure cells.
• To explain the significance of air pressure tendency for local weather forecasting.
• To describe how altitude can be determined from a pressure altimeter.

Outline:

A. INTRODUCTION

• A practical problem

B. BASIC CONCEPTS - ATMOSPHERIC PRESSURE

• What is Pressure?
• Importance of Air Pressure

C. BAROMETRY

• The Science of Barometry
• Types of Barometers
• Mercury Barometers
• Aneroid Barometers
• Placement of Barometers
• Pressure Units

D. THE CLIMATOLOGY OF ATMOSPHERIC PRESSURE

• Spatial Variation in Atmospheric Pressure
• Variation of Pressure with Time
• Variation of Atmospheric Pressure with Height

E.  ALTIMETRY - A SPECIAL APPLICATION

• The altimeter
• The background

Links to Other References:

• Educational resource unit (K-12) on air pressure from Nebraska Earth Science Education Network (NESEN):
• Elementary level To Heavy for Me!!
• Intermediate Level The Big Crush
• Secondary level Air Up There!
• The Pressure activity module from Weather World 2010 (Univ. of Illinois Urbana-Champaign).

Last revision 13 June 2000 (1325 UTC)

URL: aos100/lectures/0002bprs.html