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The most abundant ion present in seawater is
Seaward of the low tide line is called the
What property do we use today to measure the salinity of the ocean
True of False The Salinity of seawater varies from 33-38 percent
What is latent heat measured in?
What are the 3 states of matter?
To change state heat must be
absorbed or released
Adding Energy with no temperature change
Are clouds water vapor?
No they are liquid water!
Ways to measure humidity
- Think mountains
- Elevated terrains act as a barriers
- Result can b a rain shadow desert.
- Cool air acts as a barrier to warm air
- Fronts are part of the storm systems called middle-latitude cyclones.
Where the air is flowing together and rising (low pressure)
Localized convective lifting
Localized convective lifting occurs where unequal surface heating causes pockets of air to rise because of their buoyancy
The processes that lift air
- Orographic lifting
- Frontal wedging
- Localized convective Lifting
- air that DOES NOT want to rise
- Resists vertical displacement
- Cooler than surrounding air
- Denser than surrounding air
- Wants to sink
- No adiabatic cooling
occurs when the environmental lapse rate is less than the wet adiabatic rate
- An Extreme case of Stable air
- Cold pocket of air that has warm air on top and the cold air gets stuck.
- Enviormental lapse rate is greter than the dry adiabatic rate
- Clouds are often towering
Stability of air
Determines to a large degree of type of clouds that develop and intensity of precipitation
- Made of millions and millions of water droplets or tiny crystals of ice.
- 3 basic forms (Cirrus, Cumulus and Altostratus clouds)
Goes through all different height ranges (thunder clouds)
Fog forms because...
Warm air meets cold air
- Cold surface and warm air goes over the top or
- Warm surface and cold air goes over the top
warm,moist air moves over a cool surface
- Earth surfaces cools rapid
- forms during cool, clear, calm nights
- Humid air moves up a slope
- Adiabatic cooling occurs
- Cool air moves over warm water and moisture is added to the air
- Water has a steaming appearance
Frontal for or Precipitation fog
- Forms during frontal wedging when warm air is lifted over colder air
- Rain evaporates to form fog
Fog is the only major water for...
- Temperature in the cloud is below freezing
- Ice crystals collect water vapor
- Large snowflakes form and fall to the ground
- Warm clouds
- Large hygroscopic condensation nuclei
- Large droplets form
- Droplets collide with other droplets during their descent
- Common in the tropics
Forms of precipitation
- Rain (.5mm diameter) and drizzle (less then .5mm diameter)
- Rime (aka hoar frost)
Controls of wind
Pressure gradient force (isobars, Pressure gradient)
Lines of equal air pressure
Pressure change over distance
- Associated with rising air
- Often bring clouds and precipitation
- A center of high pressure
- Pressure increases towards the center
Winds are controlled by...
The Coriolis effect is...
Affects only the direction of movement
a large-scale atmospheric convection cell in which air rises at the equator and sinks at medium latitudes, typically about 30° north or south.
Seasonal reversal of wind direction associated with large continents especially Asia. In winter, the wind blows from land to sea, in the summer, from sea to land.
- Land and sea breezes
- Mountain and valley breezes
- Chinook and Santa Ana Winds
Santa Ana Winds
Warming winds caused by wind sinking on the leeward side of a mountain
How do you measure wind?
Direction and speed
- A countercurrent that flows southward along the coasts of Ecuador and Peru.
- Usually appears during the Christmas season
- Blocks upwelling of colder,nutrient-filled water
- and anchovies starve from the lack of food.
When was the strongest El Niño events?
1982-83 and 199-98
What is La Niña
- opposite of El Niño
- Triggered by colder than average surface temperatures in the easter Pacifica
What is a typical La Niña winter like?
blows colder than normal winter in the Pacific NW and the Northern Great Plains while warming much of the rest of the United States. Greater precipitation is expected in the NW.
Are Atlantic Hurricanes fewer during El Niño years of La Niña years?
El Niño years
What are Air Masses
big sections of air
Types of fronts
Warm and Cold
What is latent heat? Why is it important to our
understanding of weather?
The energy absorbed or released during a change in state.
When going between states of matter, in what ways is energy released?
What is sublimation?
the process in going directly from solid to a gas
What is deposition?
going from gas to a solid
What is Humidity?
A general term referring to water vapor in the air but not to liquid droplets of flog, cloud or rain.
What is relative humidity?
The ration of the air's water vapor content to its water-vapor capacity.
What influences the relative humidity?
the amount of water and the temperature
What is dew point?
The temperature to which air has to be cooled in order to reach saturation.
How are clouds and fog formed?
• Water vapor in the air changes to a liquid and
- forms dew, fog, or clouds
- • Water vapor requires a surface to condense on
- • Possible condensation surfaces on the ground can be
- the grass, a car window, etc.
- • Possible condensation surfaces in the atmosphere
- are tiny bits of particulate matter
• Called condensation nuclei
• Dust, smoke, etc
- • Ocean salt crystals which serve as hygroscopic
- ("water seeking") nuclei
At what time of day is it typically the coldest? The warmest?
2am and 2pm
How would we expect relative humidity to change in response to these temperature changes? (coldest to warmest)
- hold more water in warm temperatures
- Hold less in cold temperatures
What is adiabatic heating and cooling? How does it work? Under what conditions can we expect it to influence seater (i.e what processes lift air)?
Cooling or warming of air caused when air is allowed to expand or is compressed, not because heat is added or subtracted.
Is the adiabatic cooling rate faster in dry air or wet air?
What is stable air?
Resists vertical displacement
- • Cooler than surrounding air
- • Denser than surrounding air
- • Wants to sink
• No adiabatic cooling
- • Absolute stability occurs when the environmental
- lapse rate is less than the wet adiabatic rate
Under what conditions do we experience absolute stability?
When the environmental lapse rate is less than the moist adiabatic rate an air parcel cools more quickly than the surrounding air mass. This is known as absolute stability. ln this case the air parcel strongly resists lifting. If the parcel is forced to lift by mechanical means (such as orographic uplift or uplift along a frontal boundary), it will spread out horizontally.
- Acts like a hot air balloon
- • Rising air
• Warmer than surrounding air
• Less dense than surrounding air
- • Continues to rise until it reaches an altitude with
- the same temperature
occurs when the atmosphere
- is stable for an unsaturated parcel of air but unstable
- for a saturated parcel
What kind of conditions is likely to generate a strong thunderstorm?
- Warm air
- Moist air
- Instability (lifting)
What are some possible condensation surfaces for water vapor?
grass a car window particulate matter
Are clouds typically composed of water vapor the size of raindrops?
minute water droplets or tiny crystals of ice
What are the three basic forms of clouds?
What kinds of clouds are typically responsible for strong thunderstorms?
What kind of clouds are typically responsible for the long, soaking rains we get in the Willamette valley?
How and why does fog form?
- Considered an atmospheric hazard
- Cloud with its base at or near the ground
- Most fogs from because of radiation cooling or movement of air over a cold surface
What are some examples of different types of fog?
- Advection fog
- Radiation fog
- Upslope fog
- Steam fog
- Frontal fog/Precipitation fog
How and why does precipitation occur
Temperature in the cloud is below freezing, Ice crystals collect water vapor, Large snowflakes form and fall to the ground or melt during descent and fall as rain.
What process is responsible for precipitation at the middle latitudes?
What process is responsible for precipitation in the tropics?
What type of clouds would we expect to produce a tornado?
What is a supercell?
With respect to a supercell, where would we expect a tornado to be
generated (map directions)?
- A huge thunderstorms
- The southwest corner
How fast can the winds blow in a tornado? What is the most active time of the year for
tornadoes? In what direction do tornadoes usually travel in the U.S.?
- 45 kilometers or 30 miles per hour.
- April and June
How do Tornados Form
S strong wind above and a weaker wind below setting up a spinning motion. Then Instability tips the air vertically then it turns to a mesocyclone.
What is the Fujita scale?
A measure of intensity of tornados. Fujita is no longer used because it overestimated wind speeds and was only useful when manmade structures were damaged. Problematic because different assessors say different things.
At what latitudes do we see hurricanes form?
5 degrees and 20 degrees
When are tornados more frequent?
April hrough June
What are the conditions for witch a tornado needs to form?
- Occur most often along a cold front
- During the Spring months
- Associated with huge thunderstorms called super cells.
Enhanced Fujita scale
The Enhanced Fujita scale is more consistent to measure the intensity of tornados. Corrects overestimates for wind speed, allows for damage to vegetation to be considered, Includes path width and length in determination, in since Feb 2007
5 stages of Tornado Growth
- Stage 1 "Dust Whirl"
- Stage 2 "Organization stage" looks like a tornado.
- Stage 3 "Mature stage" The most damaging stage. Reaches maximum size.
- Stage 4 "Dissipating stage" Starts to shrink.
- Stage 5 "Rope Stage" looses form
Where would we expect the strongest winds of the hurricane to be located?
What is the storm surge?
What are its impacts?
- large dome of water 65 to 80 kilometers (40 to 50 miles) wide sweeps across the coast where eye makes landfall.
- Causes wind damage and flooding
What are the two principle criteria that we use to define climate?
- over a long period time
- Generalized, composite of weather
In the Köppen climate classification scheme, what are the general characteristics of climate zones A, B, C, D, and E? How do these relate to latitude?
What factors influence global climate change? How does burning fossil fuels contribute to
global climate change?
Other than CO2, what are some other atmospheric gases that
may contribute to global climate change?
What is the Little Ice Age?
What is a positive feedback mechanism? What is an example? How about a negative
What kind of heating differences would we expect to see in
the climate if solar energy increased?
What kinds of heating differences would we expect if the heating was
primarily due to greenhouse gases?
What are some possible impacts that global climate change
may bring to Oregon?
Are rain and
drizzle the same thing? What is
sleet? What is glaze? What atmospheric conditions are needed for
sleet and glaze to occur? What is hail
and in what kinds of clouds can we typically expect it to form?
If we have an area of high pressure and an area of low
pressure, in which way would we expect the winds to flow (e.g. from low to high
or from high to low?)
Do winds blow clockwise or counterclockwise around a
low? Around a high?
What three forces influence the direction and speed of the
wind at the surface of the earth? Is the
same true at high altitude (i.e. geostrophic winds)?
What is the jet stream? How many of them are there and what
do they represent?
What is a cyclone (general definition)?
Which way to winds blow around a cyclone in
the northern and southern hemispheres?
Within a cyclone, is the air rising or falling?
What about an anticyclone?
What weather conditions do we associate with
cyclones and anticyclones?
With respect to latitude, where do cyclones and anticyclones
dominate the weather patterns?
What is the fundamental driving force behind all atmospheric
(Hadley) What portions of the earth are directly influenced by this
circulation (what latitude to what latitude)?
What is the climate like where this circulation is going upwards? What is the climate like where this
What are the trade winds and where on Earth would we
expect to find them?
Where do westerly winds dominate the weather patterns?
What is the driving force behind westerly winds?
What is atmospheric circulation like in the polar regions?
From which direction do the polar winds predominantly blow?
What is a monsoon?
Why are they important?
What are Mountain and Valley Breezes? When do they
What are Chinook or Santa Ana Winds? What is their effect?
What are the weather patterns El Niño and La
Niña?How are they formed?
How would an El Niño impact the coastal waters of Peru?
How would an El Niño impact California?
How would a La Niña impact Oregon?
Would the southeastern U.S. expect to have more or fewer
hurricanes during an El Niño year?
What is an air mass?
What are the general characteristics of an air mass?
What would we expect a continental polar air
mass to be like? Maritime polar? Continental Tropical? Maritime tropical?
The big thunderstorms generated east of the Rocky Mountains
are most typically caused by what two types of air masses colliding?
What is a warm front and what are its characteristics?
How do we symbolize a warm front on a map?
What kind of cloud progression might we expect as a warm
front moves in?
What is a cold front and what are its characteristics?
How do we symbolize a cold front on a map?
What kind of clouds might we expect along the edge of a cold
What is the typical life cycle of a middle latitude
During what time of the year to we get the most
powerful middle-latitude cyclones? Why?
How big might we expect one of these middle latitude
cyclones to be?
What kind of weather would we expect from a middle-latitude
Does a cyclone require divergent or convergent air at high
altitudes? What about an anticyclone?
conditions lead to the formation of thunderstorms?
What is the life cycle of a thunderstorm?
When would we expect the heaviest rain?