NSTA Meteorology Reading 11
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Scales in Meteorology
- What Is a Scale?
‣ Scales help measure weight, distance, or temperature
‣ Temperature = one of the most important functions of meteorology
‣ Richter scale = measure seismic vibrations of Earth; measures magnitude or strength or
an earthquake
‣ 3 major temperature scales:
* Fahrenheit = water freezes at 32°F and boils at 212°F
* Celsius = freezing and boiling points of water set at range of 100°C
* Fahrenheit and Celsius based on average kinetic energy of molecules in an ideal
gas
* Kelvin = measures energy content and is based upon the random motion of
molecules; 0 kelvin = lowest temperature; water freezes at 273.15 K and boules at
373.15 K
‣ Celsius and Fahrenheit are the two main temperature scales
‣ The United States is the only place to use Fahrenheit
- Wind
‣ Meteorologists categorize air circulation according to size
‣ 4 spatial scales of atmospheric phenomena:
* Global (Planetary Scale) = largest weather elements and patterns; elements
thousands of kilometers and greater in dimension
* Synoptic (Continental Scale) = weather patterns that dominate a region
* Global and Synoptic are combined to form the Macroscale
* Mesoscale (Local Scale) = covers weather or wind patterns in a smaller area; covers
atmospheric elements from a few kilometers to 100km in the horizontal dimension
and from the surface to 1km in height
* Microscale = all atmospheric processes smaller than a kilometer
‣ Each of the scales influences on another and is influenced by the others
- Wind Scales
‣ The Beaufort Wind Scale =
* Created by Britain’s Admiral Sir Francis Beaufort
* One of the first scales based on wind speeds
* Devised in early 19th century to help sailors estimate winds based on visual
observations
* Number on scale range from 0-12
* Each number has a distinct measure of the behavior of wind on the sailing ship
* Depends upon someone looking at the ship, not the wind
‣ The Saffir-Simpson Hurricane Scale =
* Developed in the United States in 1970s
* Ratings 1-5 based on hurricane’s intensity and estimates of potential property
damage and expected flooding
* Wind speed is the determining factor in the scale
‣ The Fujita Tornado Scale (F Scale) =
* Developed in 1970s
* Categorizes tornadoes by intensity and area
* Divided into 6 categories (F0-F5)
NSTA Meteorology Reading 11
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* Estimates wind speed associated with damage caused by the tornado
The Enhanced Fujita Scale (EF Scale) =
* Updated in 2007 with and enhanced description of damage
* Had 28 damage indicators with descriptions and estimates of wind speed
All scales are used to measure some sort of phenomenon
Scales are descriptive in nature and use qualitative and quantitative data
Meteorologists use scales to help describe and predict weather