Lecture 9 Flashcards
General Circulation
The long-term(usually decadal scales) average winds(directions and speed) in the atmoshpere as a function of location.
Climate
The long-term average state of the atmoshpere.
Weather
The instantaneous state of the atmosphere.
Sensible Heat
The energy contained in the molecules as a result of their random kinetic energy.
Thermal conduction
The transfer of sensible heat through materials or gases that are in contact as a result of the collision of hot molecules with cool molecules. Note no transfer of mass required.
Thermal convection and advection
The transfer of sensible heat by movement(or exchange) of mass. Convection usually refers to vertical movement and advection to horizontal.
Is the energy budget in balance in all locations of the earth?
No
What types of forces is air usually subject to?
1) Gravity
2) Pressure
In respect to the atmosphere, what is the result of imbalances of energy on earth?
Movement of energy from tropics to poles
What happens when the net force on air is not balanced?
It moves as a function of wind
Horizontal air motion is caused by what forces and why?
Just pressure, gravity affects vertical air movement. Air tends to move from regions of high pressure to low pressure.
Pressure Gradient force
Change in pressure over some distance
Hydrostatic equilibrium
Balance between net upward pressure and downward force of gravity.
Vertical motion of air only is effected by gravity (T/F)
F
There is a parcel of air with a lower density than the air around it. What will happen to the parcel and why?
The parcel would rise due to its lighter weight than air(force due to gravity). The pressure gradient force would be the same.
Low density air moves…
upward
High density air moves..
downward
Convection
Density differences due to temperature. P=pRT
Coriolis effect
Deflection of air westward(north) and eastward (south) due to earth spinning on its axis.
Polar front
Area of convergence where cold polar air meets warmer air to form a Ferrel cell.
Intertropical Convergence Zone
The equatorial low where air rises
Why are Ferrell Cells “invisible in real time”?
- They are averaged wind flows
- If winds are averaged over decades, flows begin to appear
Atmoshperic Scales of Motion (ASM)
Motion of energy in the atmosphere characterized by different scales.
examples of Planetary ASM
Rossby(long) waves
examples of Synoptic ASM
Lows, Fronts, Hurricanes
examples of Meso alpha ASM
Squall Lines, MCC
examples of Meso beta ASM
Large thunderstorms, sea breeze fronts
examples of Meso lambda ASM
Thunderstorms, tornadoes
examples of Micro ASM
Dust Devils
Why is the measurement of Meso ASM a very modern occurence?
Lacked measurement technology in the past
