Weather Flashcards
the 5 big guiding principles of Meteorology:
- Hot air rises
- Rising air expands & cools
- As air rises, air pressure at the surface is lowered
- Air travels from high pressure to low pressure
- Cool air holds less moisture than warm air
Hot air is less ___ than cold air
dense
Add heat to gas and what 2 things happen?
- molecules move faster
2. molecules spread out
Wind forms as ___ pressure air moves to areas of ___ pressure
high; low
the layers of the Atmosphere: from the top, down
Thermosphere (550km from Earth) Mesosphere (80km from Earth) Stratosphere (50km from Earth) Troposphere (12km from Earth)
the layer of the Earth’s atmosphere that you live in
Troposphere
the coldest layer of the Earth’s atmosphere; lies directly below the uppermost layer
Mesosphere
the uppermost layer of the atmosphere
Thermosphere
the layer that contains most of the atmosphere’s ozone; above the layer that you live in
Stratosphere
Why does air pressure decrease as altitude increases?
Air pressure decreases as you go up because the majority of air is closest to the Earth’s surface due to gravity.
Explain why the temperature decreases & increases as you travel throughout the layers of the atmosphere.
The temp. decreases as you travel up in the troposphere b/c there is less air molecules the higher you go up.
The temp. increases in the stratosphere due to the ozone layer absorbing UV rays.
It decreases again in the mesosphere due to the few slow moving molecules.
It increases in the thermosphere due to the rapidly moving ions. Even though there are few air molecules, they are moving so rapidly that the temp. increases; however, it would still FEEL cold.
What gases is the atmosphere mainly composed of & what are their percents?
78% Nitrogen
21% Oxygen
1% Miscellaneous
Radiation:
the transfer of energy as ELECTROMAGNETIC WAVES
Radiation moves energy through space in…
waves, heating the Earth’s surface
Through this method of heat transfer…
the earth recieves energy from the sun
The radiation absorbed by the land, water, and atmosphere is changed into…
thermal energy
50% of Radiation is…
absorbed by the Earth’s surface
25% of Radiation is…
scattered & reflected by clouds & air
20% of Radiation is…
absorbed by ozone, clouds, & atmosphere
5% of Radiation is…
reflected by the Earth’s surface (snow & pool/ocean water)
Conduction:
the transfer of thermal energy from one material to another by DIRECT CONTACT
Air is heated by conduction near…
the earth’s surface
Thermal energy ALWAYS moves from ___ to ___ areas
warm to cold areas
When air molecules come into contact with a warm surface…
thermal energy is transferred into the atmosphere
Where is air heated by conduction?
near the earth’s surface
Convection:
the transfer of thermal energy by the circulation or movement of a fluid (liquid or gas)
Convection currents are caused by…
the unequal heating of the atmosphere
Most thermal energy in the atmosphere moves by…
convection
What are the 4 steps in convection?
- Heated air becomes less dense & rises
- Air cools, becomes more dense & sinks
- As the cool air sinks, it pushes the warm air up
- The cool air is eventually heated again by the ground & again begins to rise
This continual process for convection creates a circular movement called a…
convection current
How are convection currents created?
by the uneven heating of the atmosphere
Air Pressure Demonstration: What were the 2 methods of heat transfer used to heat the water in the soda can?
- Conduction (can was touching hot plate)
* Convection (convection currents when boiling the water)
Air Pressure Demonstration: As the water started to boil, which phase change was occuring?
Evaporation
Air Pressure Demonstration: Where was the GREATEST amount of air pressure?
Outside the can because it was a lower temperature than inside the can.
Air Pressure Demonstration: Where was the LEAST amount of air pressure?
Inside the can because it had a higher temperature than outside the can.
Air Pressure Demonstration: Explain why the can collapsed.
Air travels from high pressure to low pressure, so when the can became surrounded by the low pressure air that was above the cooler temp. water, more air went into the can, causing it to collapse.
What is wind?
moving air from high to low pressure
Winds are named by…
where they come from
How is wind created?
by differences in air pressure
Wind is generally caused by the uneven ___ of the Earth
uneven heating
___ sun rays = hotter temperatures
direct
___ sun rays = cooler temperatures
indirect
Air that is warm & less dense ___ and creates an area of ___ pressure.
Air that is warm & less dense rises and creates an area of low pressure.
Air that is cold & more dense ___ and creates an area of ___ pressure.
Air that is cold & more dense sinks and creates an area of high pressure.
There is a change in global air patterns approximately every ___.
30° latitude
What are convection cells?
the circular patterns of air movement caused by the rising & sinking of air
Global Winds:
- are part of a pattern of air circulation that moves across the Earth
- blow over longer distances in a specific direction
Local Winds:
• blow over short distances & can blow from any direction
• types: sea breeze, land breeze,
valley breeze, mountain breeze, etc.
Where are the Doldrums?
near the equator
Why is the air calm in the doldrums?
there is very little change in temperature
Doldrums - area of low pressure at the ___
Equator
Doldrums - very little wind there because of ___ rising air
warm
Doldrums - “doldrums” mean foolish because…
it would be foolish to sail in that region
Where are the trade winds?
above and below the equator
Above the equator the trade winds are steady ___ winds. Below the equator, the trade winds are steady ___ winds. (direction)
northeast; southeast
Trade Winds - between ___ & the equator
30° latitude
Trade Winds - early ___ used them to sail from Europe to the Americas
traders
Trade Winds - go from ___ to ___
east to west
The ___ ___ are another area of calm. The air is cooling & ___ here.
horse latitudes; sinking
Horse Latitudes - areas of ___ pressure caused by sinking air at ___ N & ___ S
high; 30°; 30°
Horse Latitudes - the winds are very ___
weak
Horse Latitudes - How was this area named?
Legend: ships carrying horses from Europe to America got stuck due to lack of wind & would throw horses overboard to save drinking water & make the ship lighter
Where are the Westerlies the prevailing wind?
over much of the middle and higher latitudes
Westerlies - wind belts found between ___ and ___ N & S latitude
30° & 60° N & S latitude
Westerlies - flow in the ___ direction of the trade winds (___ to ___)
opposite; west to east
Westerlies - bring most of ___ weather
our
What is the Polar Front?
where the warm air of the westerlies meets the cold air of the polar easterlies
This causes ___ weather in the region where the ___ prevail.
unstable weather; westerlies
Polar Easterlies - wind belts found in both hemispheres between the ___ and ___.
poles & 60° latitude
Polar Easterlies - named for the ___ and ___ they come from.
direction & area
Jet Streams - narrow belts of high ___ winds in the upper troposphere & lower stratosphere
speed
Jet Streams - ___ north and south
shift
Jet Streams - control the ___ & ___ of storms (inportant to meteorologists who track storms)
direction & movement
