Transcript Meteorology Notes Fill in
Meteorology (Weather)
{ Follow along in your notes packet…
http://www.youtube.com/watch?v=FMagDRCp J14 http://www.youtube.com/watch?v=tkK4_F0VK hM
Our atmosphere has 3 states of water: 1. Ice 2. Water 3. Water Vapor
Changing Forms of Water
Water changes from one phase to another as
heat energy
is either absorbed or released. We call this heat energy
latent heat
Most water enters our atmosphere through
Evaporation
The process in which a solid changes directly into a gas is
Sublimation
Changing Forms of Water
Water Vapor in the atmosphere, known as
humidity
, is controlled by rates of
evaporation
and
condensation
Temperature often controls the rate of evaporation, where as the rate of condensation is determined by
vapor pressure
When the rate of evaporation and condensation are in equilibrium, the air is
“saturated”
Humidity
Absolute Humidity
is the mass of water vapor contained in a given volume of air (the actual amount of water vapor in the air)
Relative Humidity
is a ratio of actual water vapor content of the air to the amount of water vapor needed to reach saturation We use a
Psychrometer
to measure humidity Video
Relative & Absolute Humidity
Air moves from areas of
high
pressure pressure to low The
Coriolis Effect
occurs when winds are deflected by Earth’s rotation
Air masses
are large bodies of air throughout which temperature and moisture content are similar
How Air Moves
Air masses are classified according to their source regions, which are determined by the
temperature
and
humidity
of the air masses Cold Air Masses:
Polar areas
Warm Air Masses:
Tropical areas
Masses formed over oceans:
Maritime
(moist) Masses formed over land:
Continental
(dry)
Types of Air Masses
A cool air mass is dense and won’t mix with a less dense and warm air mass- a
boundary
called a
front
forms
between
the masses Video
Types of Fronts
Cold Front
: a cold air mass overtakes a warm air mass. Cold air lifts the warm air Storms formed from a cold front are
short-lived
and sometimes
violent
If it is a slow moving cold front, the storm may be weak with light precipitation
Types of Fronts
Warm Front
: a warm air mass overtakes a cold air mass Generally produces precipitation over a
large
area and may sometimes cause violent weather
Types of Fronts
Stationary Front
: air masses move very slowly or not at all Weather produced is similar to a warm front
Occluded Front
: when a fast moving cold front overtakes a warm front and lifts the warm air
off the ground completely
Types of Fronts
Thunderstorms produce thunder and lightning. Clouds discharge
electricity lightning.
in the form of The
upper part of the
cloud carried
a positive
charge, the
lower part
carries the
negative charge.
Lighting
is the huge spark that travels within the cloud or between the cloud and ground to
equalize the electrical charges
Severe Weather: Thunderstorms
Thunderstorms have 3 stages:
1. Cumulus Stage
2. Mature Stage
3. Dissipating Stage Severe Weather: Thunderstorms
Hurricanes
: severe storm that forms over tropical oceans and whose strong winds of more than 120 km/h spiral in toward the intensely low pressure storm center
Most destructive storms on Earth
Cause rising in the sea levels with large waves called
storm surge
Severe Weather: Hurricanes
To rate a hurricane we use the Saffir-Simpson Scale : 5 categories based on central pressure, wind speed, and storm surge. Category 1: least damage Category 5: most damage Hurricanes begin over warm water….
how would Global Climate Change affect this?
Severe Weather: Hurricanes
Shortest lived severe storms, destructive, rotating column of air that has very high wind speeds and that may be visible as a
funnel shaped cloud
Forms when a thunderstorm meets high altitude, horizontal winds which cause the rising air in the thunderstorm to rotate. A storm cloud may develop a narrow, funnel-shaped, rapidly spinning extension that reaches
downward
Severe Weather: Tornadoes
To measure and indicate temperature we use a Thermometer For changes in air pressure affect air masses at certain locations or atmospheric pressure we use a Barometer Wind speed is measured with an Anemometer Wind directed is measure with a Wind Vane
Radar, weather satellites and computers are useful as well
Weather Instruments
Meteorologists and weather stations collect data and transfer it onto
weather maps
. So that everyone around the world can understand they use
symbols and colors
A cluster of weather symbols are called a
station model
: pattern of symbols that represent the weather at a particular observing station and is transferred onto a weather map
Forecasting the Weather
Isotherms
: lines that connect points of equal temperature (think: thermometer)
Isobars
: lines that connect points of equal atmospheric pressure (think: barometer) Centers marked with an “H” represent high pressure; “L” is for low pressure Areas with precipitation are marked with colors or symbols
Plotting Temp & Pressure
Doppler Radar & Satellite Images
can tell us about intensity and precipitationso that meteorologists can create weather models Types:
Daily Forecasts
: predict weather for 48 hrs
Extended Forecast
: 3-5 days
Long-Range Forecast
: more than 7 days
Watch
: conditions are ideal for severe weather
Warning
: severe weather has been spotted OR is predicted within 24 hours
Weather Forecasts
Weather conditions for an area over a long period of time is Climate Different latitudes receive different amounts of solar energy The higher the latitude, the smaller the angle at which the Sun’s rays hit the Earth and the smaller the amount of solar energy received by the area The
tilt of Earth’s axis
is also a factor
Climate
Topography
: surface features of the land can control the flow of air through a region
Rain Shadow
: moving air mass encounters a mountain range, the air mass rises, cools and loses most of its moisture through precipitation. The air that flows down the other side is usually
warm
and
dry.
Warm winds that flows down the eastern slopes of the Rocky Mountains are
Chinooks
Topography
Tropical Climates
: high temperatures and heavy precipitation during at least part of the year
Middle- Latitude Climates
: has an average maximum temperature below 18 degrees C in the coldest month and an average minimum temperature above 10 degrees C in the warmest month
Tropical Desert Climates
: dry climates that receive less than 40 cm of precipitation a year
Climate Zones
Mediterranean Climate
summer and winter : mild climate that has a small temperature range between
Tundra Climate
: smaller annual temperature range than subarctic but has a colder climate
Polar Icecap
: much of the land and ocean covered in thick sheets of ice, average temp never rises above freezing
Large bodies of water
, such as
lakes
, can influence local climates as well as precipitation