Atmospheric Stability & Instability

Stability & Instability

·         Instability - Possessing the ability to move away from the original position; allows convection and enhances vertical motions.

·         Stability - Possessing the ability to return to its original position; suppresses convection.

·         Inversion - Temperatures increasing with increased altitude, or height. A negative lapse rate.

·         Lapse rate (Γ) - The change of temperature with a change in height. Rate of decrease in temperature. Getting colder with height = Positive lapse rate. dT / dZ = temperature changing with height.

 

·         Adiabatic – not heat

·         Isotherm – A line of constant temperature.

·         Isothermometer – A line of constant dew point temperature.

·         Barometer - measures pressure

 

Air Parcel’s

·         “Blob” of air

·         Expands and contracts freely

·         Rises and sinks through the atmosphere

·         If it is warmer it is less dense then the air which makes it rise (compression)

·         If it is colder it is more dense then the air which makes it sink (expansion)

·         Temperature will change from pressure – does not exchange from inside and outside the box

·         Temperature is NOT a measure of heat

  

Types of Heat Transfer

1.    Conduction

a.    The transfer of sensible heat from a warm object to a cool object through contact

2.    Convection

a.    fluid/anything that is flowing

3.    Radiation

How Pressure changes with height?

a.    dp / dZ < 0

b.    Pressure decreases with height, which is a negative change, that is less than

1^st Law of Thermodynamics

̶        Heat In = Work + delta-T

a.    Adiabatic process:        

Warm air is less dense then cold air ONLY at the same pressure