Term
Circulation in the middle and upper
troposphere can be visualized by |
|
Definition
viewing
a constant isobaric surface |
|
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Term
Undulating isobaric surface for upper
atmosphere: |
|
Definition
– Ridges of high pressure where winds slow
and converge (pile up) in anticyclonic motion
– Troughs of low pressure where winds
accelerate and diverge in cyclonic circulation |
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|
Term
| Rossby waves are associated |
|
Definition
|
|
Term
|
Definition
| Develop in the upper-air circulation |
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|
Term
| Rossby waves bring tongues of |
|
Definition
cold air
southward, with warmer tropical air
moving northward: |
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Term
Rossby waves bring tongues of cold air
southward, with warmer tropical air
moving northward: |
|
Definition
Distinct cyclonic circulations form
– Support the development of cyclonic storm
systems at the surface
– Develop in relation to polar jet-stream flow |
|
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Term
|
Definition
is a region or band of
high winds. |
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|
Term
Two major jet streams circle the
earth at the mid latitudes |
|
Definition
( 30o to 50o
N and S) at elevations in the upper
troposphere (where jets fly). |
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|
Term
| Because these jet streams wander, |
|
Definition
they have a big influence on the
development and intensification of
storms. |
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|
Term
| What Causes a Jet Stream? |
|
Definition
The basic cause of the two major jet
streams is the rapid change in
temperature in the atmosphere in the
middle latitudes. |
|
|
Term
| Jet streams are most intense in the |
|
Definition
winter season in either hemisphere
because that is the time of greatest
temperature change from the equator
to the pole |
|
|
Term
| Jet streams characterized by: |
|
Definition
– Large temperature gradients (changes)
– Large density changes
– Large pressure gradients
– Large drop in elevation of the
tropopause
– Large drop in pressure surfaces |
|
|
Term
|
Definition
|
|
Term
|
Definition
If two nearby regions on the earth’s
surface are heated differently…
– The result is a temperature (hence
density) difference in the atmosphere
– Winds will result because of the density
difference. |
|
|
Term
|
Definition
warm, less dense air rises next
to cool denser air, which sinks. |
|
|
Term
|
Definition
Planes that connect points of equal
atmospheric pressure |
|
|
Term
| During the day, valley air heats rapidly: |
|
Definition
|
|
Term
| Mountain air cools rapidly at night |
|
Definition
Cooler air subsides down-slope into the
valley |
|
|
Term
|
Definition
stronger and occur on a
larger scale than mountain-valley breezes |
|
|
Term
|
Definition
– Ferocious winds blowing off ice sheets of
Antarctica and Greenland
– Santa Ana winds of California |
|
|
Term
|
Definition
Most notable in eastern India, parts of Indochina,
and the Philippines. |
|
|
Term
|
Definition
be destructive, but monsoons are
important for crops |
|
|
Term
|
Definition
|
|
Term
|
Definition
Ocean circulation driven by contrasts in
temperature, composition and density of
ocean waters |
|
|
Term
| Actual pathways influenced by: |
|
Definition
– Earth’s spin
– Positions of continents |
|
|
Term
| Three layers in the ocean: |
|
Definition
Surface water
intermediate water
Deep water |
|
|
Term
|
Definition
varies in temperature with
latitude and the seasons |
|
|
Term
|
Definition
is a mixing zone
between surface and deep water where
temperature may decrease significantly
with depth |
|
|
Term
|
Definition
is cold and relatively
uniform in temperature |
|
|
Term
|
Definition
Ocean water sinks when it’s density
exceeds that of surrounding water |
|
|
Term
| Higher density caused by: |
|
Definition
– Colder temperature
– Higher salinity |
|
|
Term
| Ocean water sinks near the poles because of its |
|
Definition
|
|
Term
|
Definition
| higher density than warm water |
|
|
Term
| Formation of sea ice excludes |
|
Definition
salt, so surrounding
water increases in salinity and thus density |
|
|
Term
| Migration of deep waters is |
|
Definition
slow (averages 5
km or 3 miles a day) |
|
|
Term
| Two principle deep water flows |
|
Definition
– North Atlantic Deep Water
– Antarctic Bottom Water (deepest) |
|
|
Term
|
Definition
|
|
Term
|
Definition
is in direct contact
with the atmosphere and warmed by
Sun’s energy |
|
|
Term
|
Definition
|
|
Term
|
Definition
horizontally by wind
and wave action |
|
|
Term
Relatively narrow channels of swiftmoving
surface ocean water |
|
Definition
– Velocities typically 10 km/day but locally
may attain 160 km/day |
|
|
Term
|
Definition
definite and
predictable direction |
|
|
Term
|
Definition
heat and nutrients in the
oceans |
|
|
Term
| Surface ocean currents are driven by |
|
Definition
|
|
Term
The direction of movement of the
currents is influenced by the |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
Some surface ocean currents are
continually deflected towards the right in
the northern Hemisphere (to the left in
southern hemisphere) |
|
|
Term
|
Definition
| – Examples: North Atlantic and Pacific gyres |
|
|
Term
Several system fluctuations occur in multiyear or
shorter periods: |
|
Definition
North Atlantic Oscillation where pressure differences
between the Icelandic low and Azores high alternate in
strength
– Arctic Oscillation results from variable fluctuations
between middle- and high-latitude air masses over the
Northern Hemisphere
– Pacific Decadal Oscillation involves temperature and
pressure fluctuations between the northern and tropical
Pacific Ocean over durations of 20-30 years |
|
|
Term
|
Definition
– Pacific trade winds are stronger than usual, pushing warm
surface water further west
– Results in increasing upwelling of cold water along eastern
Pacific coastlines (e.g. west coast of South America)
– Equatorial waters become cooler than normal |
|
|
Term
|
Definition
less frequently (4-12 years)
than El Niño events |
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|
