Meteorology. I.Weather- A. Causes of Weather 1. Energy from the a. Through the seasons, it heats our...
-
Upload
rosalind-porter -
Category
Documents
-
view
219 -
download
0
Transcript of Meteorology. I.Weather- A. Causes of Weather 1. Energy from the a. Through the seasons, it heats our...
Meteorology
I. Weather-
A. Causes of Weather1. Energy from the
a. Through theseasons, it heats our world,some parts more and some parts less
The state or condition of the variables of the atmosphere for a location at a given period of time.
sun
LOW latitude
b. This causes earth’s atmosphere to react and become a gigantic engine that produces an infinite variety of
uneven heating
MEDIUM Latitude HIGH latitude
weather
B. Weather/Atmospheric Variables:
1.
2.
3.
4.
C. Weather Instruments:
Temperature
Barometer
Wind (Speed and Direction)
Moisture (Precipitation and Humidity)
Air Pressure
Measures
Air Pressure
Sling Psychrometer
Measures
Relative Humidity
Rain Gauge
Measures
Rainfall
Wind / Weather vane
Measures
Wind Direction
Anemometer
Measures
Wind Speed
Thermometer measures Temperature
II. Atmosphere: The envelope of air (mixture of gases) that surrounds earth
A. Composition of the lower atmosphere (troposphere)
1. (78%)
2. (21%)
3. (.84%)
4. (.03%)
5. (.01%)
Nitrogen
Oxygen
Argon
Carbon Dioxide
Other
N + O2 + Other Gases
Oxygen
Helium
Hydrogen
Heterosphere
Homosphere
B. Composition vs. Altitude
U-V
Rays
Thermosphere
Mesopause
Mesosphere
Stratopause
Stratosphere
Tropopause
Troposphere
14
O3
Weather takes place only in the
troposphere
As altitude increases, temperature in the troposphere______________decreases
‘s atmosphere
D. Mapping a Temperature Field
1. are lines that connect to points of equal temperature. Showing temperature distribution in this way makes patterns easier to see
Isotherms
2. The greatest temperature gradient is betweenand which is
indicated because the isotherms are Richmond Hatteras
closest together
3. Temperature gradient calculation from Cincinnati to Chicago
G=(60° - 40°)
250 mi =20°F
250 mi = .08°F
mi
E. General Information – Heat and TemperatureWind Chill
2. Heat affects body- when your body is overheated the additional stress can cause medical problems.
A. Your body’s thermostat, the determines that your body is too warm.
B. increases in an effort to carry heat from deep inside the body to the surface of the skin.
C. If lost by sweating is not replaced, dehydration and heat exhaustion can result.
D. High humidity can interfere with thethat carries
away large amounts of heat.
V. Air PressureA. Cause of Air Pressure
1. The force of causes the air to have -this creates air pressure
less
more
Gravity weight
Gra
vity
Air
Pre
ssur
e
22
2. Air pressure acts equally in allit also exists within any object
containing air like a building, the human body and “empty” bottles
3.
4. Air pressure at sea level is
AIR
20,000 mi. MERCURY
30 inches
14.7 p.s.i.
14.7 lb/in22
directions;
B. Measuring Air Pressure1. Mercury Barometer 2. Aneroid barometer
An aneroid barometer consists of an air tight metal box from which most of the air has been removed.
A change in air pressure causes a small metal disk on the side or top to bend. A spring is attached to the metal disk. The bending metal disk causes the spring to move. A needle attached to the spring indicates the changing air pressure on the dial.
29.92 inches
76 cm
760 mm
Air pressure
23
3. Units for measuring air pressure Inches (of mercury) & millibars
C. Atmospheric Pressure Scale (Reference table page 13)1. Standard sea level atmospheric pressure is:
2. Conversions:
1. 997 mb =
2. = 30.15 in.
3. 1006 mb =
4. 982 mb =
5. = 29.53 in.
6. = 30.21 in.
7. 1019 mb =
29.44 in.
1021 mb.
29.71 in.
29.00 in
30.09 in.
1000 mb.
1023 mb.
One atmosphere or 29.92 in. or 1013.2 mb.
23
D. Changes in atmospheric pressure1. Factors/variables that cause atmospheric
pressure to change
a) Temperature
b) Moisture
c) Altitude
2. Effect of on air pressure:
As air temperature increases; (air molecules move farther apart/ become less dense) the air pressure decreases
temperature
24
HOT STEAMHOT STEAM Air expands
Density decreases
Vent is open
Vent is closed
COOLING STEAM
COOLING STEAM
Density increases
Air contracts
3. Effect of on air pressure:a. The diagrams represent a specific volume of air in three
different circumstances. They show how the density or mass of this volume of air changes when water vapor enters the air.
Dry
H2O
H2O H2O
H2O
Water vapor molecules replace
air moleculesHumid
More dense Less dense
moisture
24
b. As humidity increases,air pressuredecreases – because when water vapor molecules enter dry air they replace heavier air molecules
25
4. Effect of on air pressure:a.
b. As altitude increases air pressure decreases. (less air above and air is less dense)
Low
Medium
High 1013 mb.
altitude
26
c.
26
E. Mapping An Air Pressure Field1. are lines that connect
points of equal pressure. Showing air pressure distribution in this way makes patterns easier to see.
On U.S. weather bureau maps, the interval between isobars is
2. On weather maps barometric pressure is represented by a three-digit number to the upper right of a circle; this circle represents a city on the map
Isobars
4 mb
27
a. Rules to follow to determine the value of this number:
1. A decimal point is omitted between the last two digits on the right.2. The number nine or ten is omitted in
front of this number. If the original number is above 500, place a 9 in front. If it is below 500, place a ten in front. (Hint: use whichever will give a result closest to 1000 mb.)
Ex.: 053Special note: the determined value of this number should be on the pressure scale (millibars) on page 13 of the Earth Science Reference Tables
1005.3
27
On the map, draw isobars for 1004, 1008, 1012, 1016, and 1020 millibars.
VI. Wind-
A. Causes of winds1. Uneven heating of the earths surface
2. Examples:a. Land vs. water
b. Poles vs. equator
c. Dark forest vs. snowfield
3. Winds help to distribute energy from areas of surplus to areas of energy deficit.
The horizontal movement of air parallel to the earths surface
29
B. Sea Breeze Vs. Land Breeze1. Sea Breeze
COOLWARM
High
Low
Less dense
More dense
29
2. Land Breeze
WARMCOOL
Low
High
More dense
Less dense
29
C. Wind Direction1. Winds always blow from regions of
pressure to regions of pressure
2. The Coriolis Effect- Earth’s on its axis causes winds to be deflected to the in the hemisphere and to the
in the hemisphere.
highlow
rotation
right northernleft southern
30
3. a. Map View
b. side/profile view
LH
30
4. Cyclones and Anticyclones
clockwise counterclockwise
REMEMBER HI CLOCK!
31
a. Winds move in a clockwise outer spiral around a
b. Winds move in a counterclockwise inward spiral around a
Activity: On the map on page 28,a. for each station model extend the shaft of the wind arrow and draw the head of the arrow to show the “direction the wind is blowing”b. Draw larger arrows to show the general direction the wind is blowing
high pressure system
low pressure system
31
On the map, draw isobars for 1004, 1008, 1012, 1016, and 1020 millibars.
D. Wind Speed1. The speed of the wind is determined by the
difference in air pressure
2. Pressure Gradient-
3. As the pressure gradient increases, wind speed increases
Difference in air pressure between two places
31
a. Where is the pressure gradient the greatest?
b. Where are the winds strongest/highest wind?
Near Holland
Near Holland
32
E. Global WindsThe unequal distribution of solar energy (insolation), in terms of both intensity and duration, causes unequal heating of Earth. Differences in temperature cause differences in pressure which result in winds.Cooler air, being denser, sinks toward earth due to gravity. This causes warmer less dense air to rise.
Global winds or circulation on a non-rotating earth
Earths rotation causes the Coriolis Effect” which results in three (or six) cell circulation of winds as illustrated on the next page
32
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
Reference Table 14
33
IV.Moisture
A. The Water Cycle
precipitationcondensation
transpiration evaporation
absorption runoff
infiltration
8. The primary source of energy for the water cycle is the
9. is the process by which plants release water into the atmosphere; 2 in diagram
10. is the falling liquid or solid water from the clouds to earth's surface; 4 in the diagram. Examples:
A. RainB. SnowC. HailD. Sleet
Transpiration
Precipitation
sun
6. Sublimation-Ex. And7. Deposition-
B. Moisture in the Atmosphere1. The primary source of moisture in our atmosphere
is the other sources include:1. Moisture in the atmosphere exists in all three
states/phasesa. -Known as water vaporb. - tiny droplets suspended
in the air that form cloudsc. - tiny crystals suspended in
the air that form clouds.
Solid changing directly to a gas.
Moth balls Dry IceGas changing directly to a solid
Ocean
Gas
Liquid
Solid
Lakes, rivers, soil, plants
3. Is the general term used to describe the
4. determines the amount of water vapor the air can hold.
a.
b. As air temperature , the amount of water the air can hold
Humidity
Temperature
increases
increases
amount of water vapor in the air
c. At 35°C, a cubic meter of air can hold of water vapor.
5. Saturation-
6.
When air holds as much water as it can at a certain temperature
Saturation occurs when condensation = evaporation
35 grams
a. At 1, no has occurred
b. At 2, is proceeding faster than .
c. At 3, the rate of equals the rate of .has been reached and the air is
evaporation
evaporation
evaporation
condensation
condensation
Equilibriumsaturated
7. Factors affecting the rate of evaporation:
a. -
b. -
c. -
d. -
Temp.
Humidity
As temp. increases. the rate of evaporation increases
As humidity increases the rateof evaporation decreases
Wind
Surface Area
As wind increases the rate of evaporation increases
As surface area increases evaporation increases.
HumidityTemperature Wind Surface Area
9. Dew Point Temperature- The temperature to which air must be to reach saturation.
a. Using a sling psychrometer to measure the dew point temperature
A sling psychrometer consists of two thermometers mounted on a narrow frame which has a handle used to whirl it. The thermometer always remains dry (dry bulb). The other has a cloth sock or wick over its bulb that is moistened before use (wet bulb)
After a psychrometer is whirled around for a little less than one minute, both thermometers should be read.
Evaporation of water from the wick will have lowered the temperature reading on the wet bulb (if the air is not saturated). Remember: evaporation absorbs heat and is a cooling process.
16
b. The drier the air the evaporation will occur resulting in cooling. In turn the difference in temperature between the dry bulb and the wet bulb will be
c. The more humid the air, the evaporation will occur resulting in cooling of the wet thermometer. In turn the difference in temperature will be
d. At saturation the temperature difference between the dry and wet bulbs would be
faster/more
greater/more.
greater/more
lessless
smaller
0
16
10. Relative Humidity- the ratio (comparison) between the actual amount of water in the air to the maximum amount of water vapor the air can hold at a given temperature.
Reference Tables
page 1219° 5° 10° 10° -7° 3° 17°
17
a. Changing Air Temperature1.
2. If temperature increases, and moisture in the air remains the same, relative humidity will decrease.
3. Time of dayHighest Relative Humidity =Lowest Relative Humidity =
Temperature
Relative Humidity
Coolest time of day – 5:00 AMWarmest time of day – 3:00 PM
17
a. Changing in Absolute Humidity (actual water vapor content)
1.
2. If the moisture content of the air increases, and temperature remains the same, relative humidity increases.
Water Vapor
Relative Humidity
18
3. Determine the relative humidity for the following data:
11. Cloudsa. Clouds are tiny droplets of liquid water or ice suspended in air.b. Combination of conditions needed for a cloud
1. Moisture in the air2. Cooling temperatures3. Dust particles “or condensation nuclei”
Reference Table 12
51% 74% 33% 83% 70% 100% 39%
18
c. Condensation Nuclei-
1.
2. Condensation in cloud formations incorporates some of the aerosols as , and thus, these aerosols are removed from the atmosphere during precipitation. Precipitation therefore
Dust particles
Salt Particles
= Water molecules
Aerosols in the atmosphere which provide a surface for water molecules to condense on
Condensation nuclei
Cleans the air
19
d. Cooling in the Atmosphere-Adiabatic Cooling
As air , the atmospheric pressure surrounding the parcel of air decreases. Therefore the parcel of air
in volume as it rises. As it expands, it becomes When the temperature of this parcel of air falls to its
, the water vapor in the air
and a appears in the sky
Cooler.
rises
expands
dew point tempcondenses
cloud
19
19
Clouds float
•Now go to page 141 in your book to see the different types of precipitation!
12.Cloud Types
a.Key meanings
1) - wisps or curls
2) - Spread or layers
3) - heaps or piles
4) - prefix meaning “high”
5) - rain-bearing or snow-bearing
cirrus
stratus
cum
alto
nimbus
ulus
20
b.Establish a key on pg 21 and then identify these
Cloud link
20
c. Classification of clouds
CirrusCirrostratus
Cirrocumulus
AltostratusAltocumulus
StratocumulusStratus
Nimbostratus
Cumulus
Cumulonimbus21
1
23
4
5
6
78
9
10
Go back to page 20
13. Humidity and Temperature
a. The combination of high heat and humidity makes people feel warmer than the actual temperature alone. When humidity is high, less sweat evaporates. Evaporation is a cooling process, If less sweat evaporates,
b. How hot does it feel when the air temperature is 90° and the relative humidity is 70%? _______105°F
The body doesn't cool - feels warmer
Health Dangers:
Extremely Hot- heatstroke is imminent
Very Hot- Heatstroke possible with prolonged exposure. Heat cramps and heat exhaustion likely.
Hot- Heat cramps and heat exhaustion possible with prolonged exposure.
Very Warm- Physical activity could be more fatiguing than usual.
21
VII. Air masses and FrontsA. Air mass- a large body of air in the troposphere
with similar characteristics of temperature moisture and pressure.
1. Source Region- a geographic region where an air mass develops. - This happens as air stagnates over a particular part of the earths surface for a period of time acquiring the temperature and/or moisture of the surface
2. Types of Air Massesa. - originates in the tropics (low
latitudes). Characterized byb. - originates in polar regions (high
latitudes). Characterized byc. - originates in arctic regions (in
winter only), it is .d. - Originates in doldrums
near the equator. Very hot and humid. Almost never influences the U.S.
e. - originates over land masses
f. - originates over water
Tropical
Polar
Arctic
Equatorial
ContinentalMaritime
High temperatures
Low Temperatures
Very Cold/Dry
DryWet
34
3. Air masses are a combination of temperature and moisture conditions.
Symbol Name of Air Mass Characteristics
cP Continental Polar Cold + Dry
mT Maritime Tropical Warm + Moist
cT Continental Tropical Hot + Dry
mP Maritime Polar Cool + Moist
34
4. Illustrated below are the source regions of air masses that affect the weather of North America. The arrows indicate the path/tracks that these air masses follow
mP cP mP
mTmT
mT cT
35
mPmP
cP
cA
mT mT
cT
FRONTS
• The boundary between two air mass.
• Little mixing of air occurs at fronts.
• Unstableness of fronts is the cause of precipitation.
• 4 types of fronts and they are . . .
COLD FRONT
• The boundary between an advancing air mass pushing a warmer air mass.
• Underlying cold air pushes warm up and over like a plow.
• A fast moving front.
• Symbol used on maps is
WARM FRONT• The boundary between an advancing
warm air mass on a retreating wedge of a cold air mass.
• Warm air rises up and over as its advances because it is less dense.
• A slow moving front.
• Symbol used on maps is
OCCLUDED FRONT
• Occurs when a cold front overtakes a warm front and pushes the warm air between them up off the ground.
• Symbol used on maps is
STATIONARY FRONT
• Boundary between two adjacent air masses of different characteristics remaining in approximately the same position.
• Symbol used on maps is
Symbols point in the direction the air mass is moving.
STORM TRACKS
• Low pressure storms generally track (move) to the east (or northeast) across the United States.
• Due to the wind belt in which the United States is located.
ESRT p 14
WEATHER PREDICTION
• Weather prediction is based on probability.
• A few days predictions are more accurate and reliable than long term predictions.
• Computer analysis and satellite images have improved forecasting in recent years.
VIII. Areas of RainfallA. Regions on Earth where air rises expands
cools (to dew point temp), condenses, clouds + precipitation.
1. Windward Side of Mountain
Prevailing westerlies
PacificSeattle Spokane
risesexpands
cools
condenses
windwar
d
leeward
sinks
compresses
warmsdry
2. Doldrums- The equatorial region where warm humid air rises as a result of convection. This produces thunderstorms almost daily. Reference Table 14
coolsexpands
riseswet
condenses
Dry Dry
De
sert
s
De
sert
s
Tro
pica
l R
ain
Fo
rest
s
IX. Weather MapsA. Station Models – On weather maps the weather conditions
for each weather station are shown by symbols arranged in and around a small circle. These symbols and the circle makeup a station model, which gives the latest readings for the most important weather variables.
40
The Weather Station Model
©Steve Kluge 2007 Some images from the NYSED Earth Science Reference Tables
Get accompanying notes here
Draw a Station Model link
C. Weather Map1. Synoptic (a map that describes current weather and is used
for prediction)
2. Satellite Map
D. Lake Effect Snowfall
rises expandsco
ols