Flashcards in Weather Deck (183):
the 5 big guiding principles of Meteorology:
1. Hot air rises
2. Rising air expands & cools
3. As air rises, air pressure at the surface is lowered
4. Air travels from high pressure to low pressure
5. Cool air holds less moisture than warm air
Hot air is less ___ than cold air
Add heat to gas and what 2 things happen?
1. molecules move faster
2. molecules spread out
Wind forms as ___ pressure air moves to areas of ___ pressure
the layers of the Atmosphere: from the top, down
(550km from Earth)
(80km from Earth)
(50km from Earth)
(12km from Earth)
the layer of the Earth's atmosphere that you live in
the coldest layer of the Earth's atmosphere; lies directly below the uppermost layer
the uppermost layer of the atmosphere
the layer that contains most of the atmosphere's ozone; above the layer that you live in
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?
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...
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)
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
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...
What are the 4 steps in convection?
1. Heated air becomes less dense & rises
2. Air cools, becomes more dense & sinks
3. As the cool air sinks, it pushes the warm air up
4. 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...
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?
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
___ sun rays = hotter temperatures
___ sun rays = cooler temperatures
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 ___.
What are convection cells?
the circular patterns of air movement caused by the rising & sinking of air
• are part of a pattern of air circulation that moves across the Earth
• blow over longer distances in a specific direction
• 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 ___
Doldrums - very little wind there because of ___ rising air
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)
Trade Winds - between ___ & the equator
Trade Winds - early ___ used them to sail from Europe to the Americas
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 ___
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
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
Jet Streams - ___ north and south
Jet Streams - control the ___ & ___ of storms (inportant to meteorologists who track storms)
direction & movement
Jet Streams - pilots fly with the jet stream when possible to ___ time & fuel
Coriolis Effect - ___ winds are affected by the coriolis effect
Coriolis Effect - the apparent ___ of winds because of the Earth's ___.
Coriolis Effect - winds in the Northern hemisphere appear to curve to the ___
Coriolis Effect - winds in the Southern hemisphere appear to curve to the ___
A convection current is an alternating cycle in which ___ air is constantly being replaced by ___ air
Heat is released (energy is lost) in which phase changes?
condensation, freezing, deposition
Heat is absorbed (energy is added) in which phase changes?
evaporation, melting, sublimation
What is precipitation? What is the phase change?
rain, snow, sleet, or hail that falls from the clouds onto the Earth's surface; liquid to solid
What is infiltration?
the movement of water into the ground due to the pull of gravity
What is runoff?
water that flows across land & collects in rivers, streams, & eventually the ocean
What is groundwater?
the water located within the rocks below the Earth's surface
What are glaciers? What is the phace change?
an enormous mass of moving ice; solid to liquid
What is an example of perspiration? What is the phase change?
sweating; liquid to gas
What is transpiration? What is the phase change?
the process by which plants release water vapor into the air through their leaves; liquid to gas
What is wind?
moving air (moves high & low pressure)
What is Humidity?
the amount of water vapor or moisture in the air
As water evaporates, does the humidity of the air increase or decrease?
As water evaporates, the humidity of the air increases.
What is Relative Humidity?
the amount of moisture the air contains compared with the maximum amount it can hold at that particular temperature
How can the relative humidity become higher? (2 ways)
1. more water vapor in the air at a particular temperature
2. lower temperature with a particular amount of water vapor in the air
What is Condensation?
the change of state from a gas to a liquid
What % relative humidity will there be condensation?
Condensation is when a gas changes to a liquid when the air is saturated with 100% relative humidity.
What is Dew Point?
the temperature at which air must cool to be completely saturated
How is there condensation on a glass with ice in it?
the ice in a glass of water causes the air surrounding the glass to cool to its dew point, making the relative humidity 100% & causing condenstion to form
What is Saturated?
when air holds all the water it can at a given temperature
What is the relative humidity of saturated air?
Saturated air has a relative humidity of 100%
How is relative humidity found using a Psychrometer?
by taking the difference between the Dry-Bulb temperature and the Wet-Bulb temperature. then a chart is used to find the relative humidity.
What happens to relative humidity as air temperature increases?
relative humidity decreases as air temperature increases
What is a River?
a large natural stream of water flowing in a definite course that empties into an ocean, lake, or another body of water
What are Tributaries?
smaller streams or rivers that flow into bigger ones
What is a Watershed?
the land drained by a river system - the main river & tributaries are within it
What are Wetlands?
the area around the mouth of a river tht has fertile soil and marsh, freshwater, and saltwater habitats
What is a Delta?
a fan shaped deposit of sediment where a river slows down as it reaches a large body of water
What is an Ocean?
a large body of salt watet
What is Sediment?
Why are river systems & the water cycle classified as CLOSED LOOP SYSTEMS? Tell the difference between open & closed systems.
River systems & the water cycle are both classified as closed loop systems because neither of them are dependent on things outside of their system. In the river system & water cycle, water flows continuously & the systems are never-ending. They don't need, for example, a human to continue the cycle by moving water from 1 place to another. An open loop system is dependent on outside factors to continue it's cycle.
What are the basic ingredients for weather?
temperature, pressure, volume, density
What do all weather events have in common?
Altitude: Stratus Cloud
below 6,500 ft (low)
Composition: Stratus Cloud
What they look like: Stratus Cloud
grey clouds that cover the entire sky; layered
Weather/Precipitation: Stratus Cloud
drizzle (very light rain)
Altitude: Nimbostratus Cloud
below 6,500 ft (low)
Composition: Nimbostratus Cloud
What they look like: Nimbostratus Cloud
dark grey; wet-looking; layered
Weather/Precipitation: Nimbostratus Cloud
continuously falling rain or snow (light to moderate)
Altitude: Stratocumulus Cloud
below 6,500 ft (low)
Composition: Stratocumulus Cloud
What they look like: Stratocumulus Cloud
low lumpy clouds; usually some blue sky in between
Weather/Precipitation: Stratocumulus Cloud
can become nimbostratus
Altitude: Altocumulus Cloud
6,500 - 18,000 ft (middle)
Composition: Altocumulus Cloud
What they look like: Altocumulus Cloud
grey puffy masses; sometimes in waves or bands
Weather/Precipitation: Altocumulus Cloud
indicates possible thunderstorms by late afternoon
Altitude: Altostratus Cloud
6,500 - 18,000 ft (middle)
Composition: Altostratus Cloud
water droplets & ice crystals
What they look like: Altostratus Cloud
layered across the sky; bumpy
Weather/Precipitation: Altostratus Cloud
often form ahead of storms with continuous precipitation
Altitude: Cirrus Cloud
above 18,000 ft (high)
Composition: Cirrus Cloud
What they look like: Cirrus Cloud
Weather/Precipitation: Cirrus Cloud
fair, pleasant weather
Altitude: Cirrostratus Cloud
above 18,000 ft (high)
Composition: Cirrostratus Cloud
What they look like: Cirrostratus Cloud
thin; sheet-like; can see the sun/moon through clouds (halo around moon)
Weather/Precipitation: Cirrostratus Cloud
predicts rain or snow within 12-24 hours
Altitude: Cirrocumulus Cloud
above 18,000 ft (high)
Composition: Cirrocumulus Cloud
What they look like: Cirrocumulus Cloud
small, rounded white puffs
Weather/Precipitation: Cirrocumulus Cloud
fair, but cold weather
Altitude: Cumulus Cloud
below 6,500 ft (vertically developed)
Composition: Cumulus Cloud
What they look like: Cumulus Cloud
puffy clouds; look like cottonballs
Weather/Precipitation: Cumulus Cloud
Altitude: Cumulonimbus Cloud
6,000 - 50,000 ft (vertically developed)
Composition: Cumulonimbus Cloud
water droplets & ice
What they look like: Cumulonimbus Cloud
towering, dark clouds
Weather/Precipitation: Cumulonimbus Cloud
heavy rain; thunderstorms; hail; tornadoes
If you were outside for a day & were looking at the clouds fro time to time, what would you see that would indicate precipitation was on the way?
the clouds would become darker & their altitudes would become lower
What is an air mass?
a large body of air that has similar temperature & moisture throughout the whole air mass
What is a front?
sharp transition zone
Where do air masses form?
the land or the sea
What is a Maritime air mass?
an air mass that forms over water; it is wet/moist
What is a Continental air mass?
an air mass that forms over land; it is dry
What is a Polar air mass?
an air mass that forms over polar regions; it is cold
What is a Tropical air mass?
an air mass that develops over the Tropics; it is warm/hot
Describe the maritime Tropical (mT) air mass.
warm & moist
Describe the continental Tropical (cT) air mass.
hot & dry
Describe the maritime Polar (mP) air mass.
cold & showery (wet; precipitation)
Describe the continental Polar (cP) air mass.
cold & dry
What is a front?
a front is a boundary between 2 different air masses
All of the ___ & ___ is the same behind the front
moisture & air temperature
How does a cold front form?
the cold air mass moves under a warm air mass & moves the less dense warm air out
Weather: As the cold front passes there is a sudden drop in...
Weather: As the cold front passes there is heavy...
Weather: As the cold front passes there is a sharp drop in...
Weather: As the cold front passes there are shifting/increased...
After the cold front passes, what is the weather like?
1. colder temperatures
2. decrease in precipitation
3. lowered humidity
How does a warm front form?
a warm air mass meets & overrides a cold air mass
Weather: As the warm front passes temperature...
Weather: As the warm front passes there is light...
precipitation over a large area
Weather: As the warm front passes there is minimal change in...
After the warm front passes, what is the weather like?
1. temperature becomes warmer
2. no precipitation
3. usually nice weather
How does a stationary front form?
a cold front meets a warm front and stalls - no movement
Weather: As the stationary front passes there is similar weather as a...
Weather: As the stationary front passes there is little...
Weather: As the stationary front passes the weather may last...
over several days
How does an occluded front form?
the cold air mass from the cold front meets the cool air that was ahead of the warm front. the warm air rises as these air masses come together
Type of Weather for an Occluded Front: mature...