Meteorology Text Chapter 11: Scales in Meteorology
I. What is a Scale?
A. Scale: Tools used to measure weight, distance, and temperature
i. Temperature is one of the most important functions of meteorology
B. What purpose to scales in have in science in general?
i. Geologists use a scale to measure the power and destruction of earthquakes.
1. The Richter Scale
2. Measures seismic vibrations
ii. Temperature has 3 major scales
1. All are measures of heat energy and molecular motion
a. Fahrenheit
i. Historic English system of measuring temp.
ii. Water freezes at 32 degrees
iii. Water boils at 212 degrees
b. Celsius
i. Based on freezing and boiling points of water
ii. Water freezes at 0 degrees
iii. Water boils at 100 degrees
c. Kelvin
i. Measure energy constant and based on the random
molecular movement
ii. Absolute Zero: The ceasing of molecular movement
iii. Water boils at 273.15 degrees
iv. Water boils 373.15 degrees
iii. In meteorology, the primary scales used to measure temperature are
Fahrenheit and Celsius.
1. Most of the world uses Celsius
2. America uses Fahrenheit
*Map showing the countries using Fahrenheit (red) vs. countries that use Celsius
iv. Conversion equations between scales:
1. Fahrenheit = 32.0 + 9/5 degree C
2. Celsius = 5/9 (Degree F – 32.0)
3. Kelvin = Degree Celsius + 273.0
II. Wind
A. Meteorologist categorize air circulations according to size
i. Global
1. Also known as the Planetary Scale
2. Consists of the largest weather patterns and elements
a. General circulation features: Trade winds, Prevailing
westerlies, Possby waves, and jet streams
b. Also includes regions of the atmosphere such as the tropics, the
midlatitudes, the polar regions, and the ozone layer
ii. Synoptic
1. Also known as the Continental scale
a. Includes high and low pressure systems, air masses, and frontal
boundaries
iii. Mesoscale
1. Known as the Local Scale
2. Covers weather patterns over a smaller area
a. The atmosphere conditions from a few Km to 100 Km
horizontally and 1Km in height
3. Includes:
a. Squall Lines
b. Thunderstorms
c. Tornadoes
d. Small Tropic Depressions
e. Local wind produced along shoreline
iv. Microscale
1. Includes all atmospheric processes smaller than a kilometer or so
a. Individual clouds
b. Small eddies interactions with trees or buildings
v. The global and synoptic scales are often referred to in combination as the
Macroscale.
B. Weather in one scale effects another
III. Wind Scales
A. The Beaufort Scale:
i. 12 category range
ii. Demand that the observer not look to the wind, but the “ship”
1. Stages 0-4: Describe the wind in terms at which the boat is being
propelled
2. Stages 5-9: Represent how well the sails carry wind
3. Stages 10-12: Reflection of the survival ability of the sails and ship
due to high winds.
B. The Saffir-Simpson Hurricane Scale
i. Developed by the U.S. in the 1970’s
ii. A scale with ratings of 1-5 based on a hurricane’s intensity
1. Category 1: Sustained winds between 74-95 mph
2. Category 2: Sustained winds between 96-110 mph
3. Category 3: Sustained winds between 111-130 mph
4. Category 4: Sustained winds 131-155 mph
5. Category 5: Sustained winds greater than 155 mph
C. The Fujita Tornado Scale:
i. F0- Gale
ii. F1-Weak
iii. F2- Strong
iv. F4- Devastating
v. F5- Incredible
IV. All scales are used to measure some sort of phenomenon such as weight, distance, or
temperature, using system of defined marks set at fixed intervals
A. Scales are largely descriptive and are used for both qualitative and quantitative
measuring and data.
All information referenced from Project Earth Science: Meteorology 2nd edition
Cohen, Robert A. and Veal, William R. Project Earth Science: Geology Revised Second Ed.
Arlington, VA: NSTA Press, 2011. Print.