Unit 3 Flashcards
Atmosphere and Weather
What Is the atmosphere?
mixture of gas and particles we call air. It shields us from harmful UV radiation
What is temperature?
how fast atoms are vibrating in a material, faster vibrations = more heat
What is heat?
it is a measure of a materials total energy, its produced when particles collide
Latent Heat
Heat released when there is a change of state, ex Water to ice
What is atmospheric density?
Number of air molecules in each unit of volume
Atmospheric pressure
The force of the air weighing down over a unit of area
What is the four layers of the atmosphere?
Troposphere, stratosphere, measophere, thermosphere
In what conditions do pressure and density decrease?
They decrease when the altitude decreases
Warm air molecules take up more space which affects pressure and density in what way?
Air pressure and density are lower when there is warm air
Cold air molecules take up less space which does what to air density and pressure?
Pressure and density are higher when the air is cold
What is the temperature gradient?
Change in temperature with distance - This is determined by the heat source of the layer
What is the first layer of the atmosphere?
the troposphere, Temperature is highest here because it absorbs energy from the earth. Weather ONLY occurs here
What is temperature inversion?
When the temp gradient in the troposphere flips. was cold air over warm, now its warm over cold. Usually form when land is cool at night or when the sea water cools the air above
What is the second layer of the atmosphere?
stratosphere, contains the ozone layer, This absorbs most of the UV radiation which protects life on earth
what is the third layer of the atmosphere?
Mesosphere, low density and pressure. Its heated by the layer underneath which is the stratosphere (coldest layer)
What is the fourth layer of the atmosphere?
gets its heat from solar radiation, contains majority of the ionosphere
What is the Ionosphere and where is it located?
Primarily in the thermosphere, reflects radio waves used for communication, solar radiation ionizes gas molecules
What causes auroras?
It is the result of the disturbances in the magnetosphere caused by solar wind
What is wind?
movement of air caused by the heating of earths surface its produced by atmospheric pressure but is affected by the coriolis force
Why does it rain?
Warm air (rising) can hold more moisture than cooling air (descending) When warm air rises in a low pressure zone clouds form and precipitation occurs
Local winds
They are winds that result from air moving between small low and high pressure systems
Hadley cells
Warm moist air near equator causes precipitation, this releases heat causing air to rise, the air flows towards the poles in a clockwise manner
What is the coriolis force?
this is cause by earths rotation which is essentially an invisible force deflects wind
What is the pressure gradient?
the rate of change of atmospheric pressure over a horizontal distance
What is a front?
a boundary between warm and cold air masses
What is jet stream?
fast flowing rivers of air at the boundary of the tropo and stratosphere, they form when there us a large temperature difference between the masses,. They only flow west to east.
What is weather?
what is happening in the atmosphere at a particular time and place
What is climate?
the average of a regions weather over time
What is humidity vs relative humidity?
Humidity is the concentration of water vapour in the air where as relative humidity is the amount of moisture present relative to the amount that would be present if the air was saturated (dew point)
When does precipitation occur?
when humidity is greater than 100%
What are clouds?
they are visible aerosols consisting of liquid water droplets, ice particles or a mixture of the two
How do clouds influence weather?
they prevent solar radiation from reaching suns earth, they create precipitation, as well as absorbing wrath that is reemitted from the ground
cloudless day
Hot weather
cloudless night
cold weather
What are the two ways a cloud can form?
- air temp stays constant but humidity increases, or 2. humidity stays constant and temperature declines
High level clouds
Form from ice crystals. Cirro-form clouds, Strato-form, Nimbo-form
mid level clouds
form from ice crystals or h2o droplets, cumulo-form, Strato-form, Nimbo-form
low level clouds
form from h2o droplets, cumulo-form, Strato-form
what is fog?
water droplets or ice crystal’s suspended near earths crust
What are air masses?
a body of air with horizontally uniform temperature, humidity and pressure.
What are the four main types of air masses?
Maritime tropical (moist wet air), Continental tropical (dry, warm air) Maritime polar (moist cold air) Continental polar. Warm masses flow towards the pole, whereas cold masses flow to the equator
What is a cold front?
when a cold air mass is replacing a warm air mass
What is a warm air mass?
when a warm air mass is replacing a cold air mass
What are cyclones?
a large air mass that is rotating around a strong low pressure zone surrounded by a high pressure zone
what are the steps to from a hurricane?
warm ocean that has overlying warm air, then low altitude winds blow into a low pressure zone, rising air form a cloud, condensation releases latent heat, this creates a heat cycle, the coriolis effect causes rising air to spiral, global wind patterns blow the hurricane across earth
