Meteorology (Atmospheric Science)

• Definition: the study of the atmosphere and the processes that produce weather and climate

A. Earth - our home - is a unique and beautiful entity. It is also a complex entity because it is not static.

• It is a dynamic place with many interacting parts that form a complex and continuously interacting whole - "Earth System".
• A change in one part of the Earth System can produce changes in one or any of all of the other parts.

• biotic - living; abiotic - nonliving; all four spheres are interconnected
• Atmosphere - a thin layer of gases (below 480 km) surrounding the Earth, and held to the Earth by gravity; it forms a protective boundary between outer space and the biosphere
• Hydrosphere - an abiotic open system that includes all of the Earth’s waters (surface, atmosphere, & crustal; & gaseous, solid, & liquid)
• Lithosphere - the Earth’s crust and that portion of the upper mantle directly below the crust that extends downward to 70 kilometers (km) (45 miles)
• Biosphere (ecosphere) - that area where the atmosphere, hydrosphere, and lithosphere function together to form the context within which life exists.
• it is an interconnected web that links all organisms with their physical environment
• just as the other three spheres impact and shape life, life itself impacts and shapes the other three spheres

• our sun & solar system is within the Milky Way Galaxy - just one of millions within the universe
• our sun is just one of billions within the Milky Way Galaxy
• the Milky Way Galaxy is a "Spiral Galaxy", and we are located far out from the center of the galaxy on one of the spiral arms - the "Orion Arm"

• speed of light: 299,792 km/sec
• at this speed, the distance that light can travel in one year is more than 9 trillion km
• this distance is called a "light year"
• we use the "light year" as a distance unit
• 1 light year = 9,454,000,000,000 km
• our moon = 1.28 seconds away in light speed
• our solar system’s diameter = 11 hours in light speed
• our entire galaxy ~ 100,000 light years
• the entire known universe ~ 12 billion light years

"nebula hypothesis":

• our solar system formed from a rotating, cloud of gas, dust, and ice - a "nebula" (4.6 billion years ago)
• a proto-Sun formed at the center of the nebula where the most mass existed
• the rotating cloud of gas and dust flattened out an assumed a disk shape
• mass accumulated by "accretion" away from the center of the nebula - protoplanets
• the protoplanets grew in size - "planetesimals"
• as the proto-Sun grew in size it became hotter due to intense pressures; and eventually thermonuclear reactions within the sun occurred - fusion - the conversion of hydrogen to helium - which releases tremendous amounts of energy

Weather/Climatic Elements:

• air temperature
• humidity
• cloud cover - type & amount
• precipitation - type & amount
• atmospheric pressure
• wind - speed and direction

1) Mass .... SI unit is the kilogram (kg)

(1 kg = 1,000 grams)

2) Length .... SI unit is the meter (m)

(1 m =100 cm; 1km = 1,000 m)

1 nautical mile =1.15 statute mi.

1 km = .621 miles

3) Time .... SI unit is the second (s)

• mass, length, and time are "scalar quantities" - they are specified only by a "magnitude"
• Vector quantities: are specified by magnitude and direction

1) Speed (v) - change in distance / the change in time

examples: miles/hour; meters/secs; km/hr

1knot = 1 nautical mile/hour = 1.15 statute mi/hr; 1 m/s = 2.24 mi/hr

2) Velocity (V) - speed in a given direction

3) Acceleration (a): change of velocity in time

• can result from a change in speed and/or a change in direction

Newton’s 2nd Law: F = m x a

Units: kg x ms^-2 = 1 Newton
 
 

Note: weight (w) is actually a force. It’s a measure of the force exerted by a mass under the acceleration of gravity (g).

w = m x g (g = 9.8 ms^-2)

• near Earth’s surface 1 Netwon=.2248lbs

• Kinetic Energy (KE): 1/2 mv²

6) Pressure (p): force per unit area (F/A)

Force exerted by air molecules

100 pascals = 1 millibar (mb)

1 inch of mercury = 33.86 mb

average atmospheric pressure at

sea level = 1013.25 mb = 1 std. atmosphere

=29.92 in mercury (Hg)

=14.7 pounds/square inch (psi)

Sea Level Pressure

1084 mb - highest ever recorded (Agata, Siberia Dec. 31, 1968)

1050 mb - a strong high

970 mb - a strong low

870 mb - lowest press. ever recorded (Typhoon, Pacific Ocean, Oct. 12, 1979)

7) Temperature (air):

• a quantity that tells us how hot or cold something is relative to some standard value
• a measure of the average kinetix energy of the air molecules
• a measure of the average speed of the atoms and molecules that comprise air. (Higher temps correspond to faster average temperatures.)

Fahrenheit (⁰F) 32 F = freezing point of water

212 F = boiling pt. of water

Celsius (⁰C) 0 C = freezing pt. of water

100 C = boiling pt. of water

Kelvin Scale (Absolute scale)

0 K = coldest possible temp = no molecular motion

273 K = freezing pt. of water = 0 Celsius =32 F

373 K = boiling pt of water = 100 Celsius = 212 F

** 1 degree of Celsius = 1 degree Kelvin * *

Temperature Conversions:

C = K - 273, K = C + 273

C = 5/9(F - 32); F = 9/5C + 32
 
 

E. Conversion of Units

• It is often necessary to convert from one system of units to another, or from one unit to another of the same type but of different size.
• Say, for example, we wish to convert 8 feet to its equivlent value in inches. We need to use a conversion factor - which has a value of 1.
• Consider the fraction 12in/1ft. The numerator and denominator are equal, so the value of the fraction is 1. Thus, we can multiply by this fraction without changing the physical length, but we do change the unit in which it is measured.

8ft = 8ft/1 X 12in/1 ft = 96 ft in/1 ft = 96in
 

Exercises:
 

• Let’s convert from 90km to its equivalent in meters:

• Let’s try another, 90 km to miles:

• One more, 35cm to inches: