Atmospheric teleconnections and ocean Flashcards
global circulation is driven by
the unequal heating of earth’s surface
thermo disequilibrium
the idea that if air is warmer then the surrounding air then that warm air will float
gases that are ____ _(light or heavy) float higher
lighter
gases that are ____ _(light or heavy) float lower
heavy
jetstream
boundaries between hot and cold air (separates fronts)
fronts
the transition zone between two different air masses at the Earth’s surface (each air mass has unique temperature and humidity characteristics)
trade winds
winds converging at the equatorial low
were are trade winds often found
in the tropical zone
air must ____ in order to have rainfall
rise
examples of trade winds
- Northeast trades
- Hadley cells
- doldrums
were are Northeast trade winds found
northern hemisphere
Hadley cells
air and wind moving between subtropics and the ITCZ
doldrums
equatorial calms where the wind is displaced upwards
is there wind in doldrums
NO
where do doldrums often happen
at the equator
Rossby waves are found
in the westerly flow of geostrophic winds
motion of Rossby waves
great waving undualtions
where do Rossby waves occur
along the polar front (where colder air meets warmer air)
where do Rossby waves occur
along the polar front (where the colder air meets warmer air)
what happens to Rossby waves at they mature
circulation patterns form where warmer and colder air mix along distinct fronts
what is associated with the position of jet streams
Rossby waves
jet streams
bands of fast wind occurring at several different locations
what do jet streams influence
surface weather systems
when do jet streams weaken
summer
when do jet streams strengthen
winter
two examples of jet streams
- polar jet stream (PFJ)
- subtropical jet stream (STJ)
polar jet stream (PFJ) meanders between
30 degrees and 70 degrees North
Subtropical jet stram (STJ)
subtropical latitudes near the boundary between tropical and mid-latitude
Subtropical jet stream meanders
from 20 degrees to 50 degrees North
what jet stream is shown by the triangle
polar jet stream
what jet stream is shown by the rectangle
subtropical jet stream
1
equatorial low
2
tropical tropopause
3
midlatitude tropopause
4
subtropical jet stream
5
subtropical high
6
trade winds
7
polar jet stream
8
westerlies
9
arctic tropopause
10
polar front
where does the rising air of the equatorial low move
poleward until the subtropical jet stream
what makes up the Hadley cell
- equatorial low with its rising air
- equatorial low winds moving polewards
- equatorial low winds reaching the subtropical jet stream and falling
- from the subtropical high
- winds travel from subtropical high to equatorial low
does falling air have rain
NO
some of the rising equatorial low moves past the subtropical jet stream to the
polar jet stream
are the westerlies extratropical or tropical
extratropical
three tropopauses in the global atmospheric circulation patterns
- tropical tropopause
- midlatitude tropopause
- arctic tropopause
what jet stream has MORE power
polar jet stream
the polar jet stream NORTH of us creates
warm conditions
the polar jet stream SOUTH of us creates
cold conditions
what is associated with the equatorial low
clouds and rain
what is associated with the subtropical high
hot, dry desert air
what is associated with the midlatitude circulation
cool and moist air
what is associated with polar circulation
frigid, dry desert air
what does the steep face of the advancing cold air mass reflect
the ground-hugging nature of cold air
what happens to warm moist air when it meets a cold front
lifts upwards abruptly
what shape is a cold front depicted as
a line with triangular spikes that point in the direction it is moving
what is the shape of a cold front
convex shape
is a cold front long or short distances
short
what kind of precipitation is expected in a cold front
intense precipitation (thunder) but with a short duration
where can warm air masses be carried and how
by jet steams into regions with colder air
can the leading edge of a warm air mass displace cooler air
NO
why cannot warm air displace colder air
colder air is more dense then warmer air
what happens to the colder air when met with a warm front
it is pushed under to form a wedge shape
_____ air slides up over _____ air in warm front
warm over cold
what kind of clouds are formed in a cold front
cumulonimbus (puffy rain/thunder cloud)
warm fronts are large or short distances
large
what is the shape of a warm front
wedge shape
true or false
a warm front is faster then a cold front
false - its slower
what kind of precipitation can be expected from a warm front
low intensity but long duration
precipitation is caused by
displaced air vertically
true or false
atmospheric and oceanic systems are intimately connected
true
how are atmospheric and oceanic systems connected
the driving force for ocean currents is the frictional drag of the winds
what are other important forces that shape ocean currents
- Coriolis force
- density differences caused by temp and salinity
- configuration of the continents and ocean floor
- astronomical forces that cause tides
examples of ocean currents
- surface currents
- equatroial currents
- thermohaline circulation (deep currents)
true or false
ocean current flow is deflected by the Coriolis force
true
how does the deflection of ocean currents due to the Coriolis force differ compared to atmospheres
they are NOT as tightly circular
where are ocean currents driven by the atmospheric circulation
around subtropical HIGH PRESSURE cells
oceanic circulation system is known as
gyres
how do winds and oceans move in the Northern Hemisphere compared to Southern Hemisphere
NH - move clockwise about high-pressure cells
SH - the opposite
equatorial currents
trade winds drive the ocean surface waters westward in a concentrated channel along the equator
why do equatorial currents remain near the equator
because of the weakness of the Coriolis force
western intensification
as surface currents approach the western margin of the oceans, the water piles up against the eastern shores of these continents
how does water pile up
by water taking place of the water that had become displaced
where does piled-up water go
spilling northward and southward in strong currents
upwelling current
- where surface water is swept AWAY from a coast
what can cause upwelling currents
- surface divergence
- offshore wind
____ water is generally rich in nurtients
cool
downwelling current
occur in areas of ACCUMULATION of water
where can downwelling currents occur (example)
western end of an equatorial current
what do the upwelling and downwelling flows redistribute
heat energy and salinity over the globe
thermohaline circulation AKA
deep currents
what is known as the thermohaline circulation
differences in temp and salinity produces density differences important to the flow of deep currents on Earth
what happens when warm, salty air mixes with cold water of the Arctic Ocean
the air cools, increases in density and shrinks
atmospheric teleconnections
climate anomalies are related to each other at LARGE DISTANCES
what is the main point of atmospheric teleconnections
something that happens far away influences the weather patterns in another area far away
what are atmospheric teleconnections linked to
ocean currents and surface weather
regional oscillations in global circulation patterns can cause ________ lasting long or short periods of time
fluctuations in temp and air pressure
most famous oscillation
El Nino-Southern Oscillation (ENSO)
what is associated with the ENSO
- shifting of air pressure
- shifting of winds
- shifting of sea surface temps (SST)
what was influenced by the ENSO
marine ecosystems
global precipitation
storm movement
what is the norm in equatorial Pacific
consistent trade winds drag warm surface waters AWAY from the South American coast = upwelling of colder nutrient rich water from below
what does El Nino look like in the equatorial Pacific
a periodic warming of coastal temps that temporarily lowers the productivity of local fisheries
if there is no upwelling cold current then there is
less fish
can pressure patterns and surface ocean temps shift from their usual locations
yes
what happens when winds and ocean currents no longer pull warm surface water westward
the thermocline lowers in-depth and upwelling stops
when do ENSO roughly occur
every 3 to 7 years
true or false
intensity and frequency of ENSO events _____ during 20th century
increased
what is the opposite of El Nino
La Nina
La Nina AKA
ENSO cool phase
El Nino AKA
warm phase
La Nina
when the surface waters in the central and eastern pacific COOL to below normal by 0.4 degrees Celcius
small temp changes can have
large climate impacts
La Nina compared to El Nino
weaker and less consistent
what has ENSO been linked to
intense weather
short-term climate effects across the globe
what are some correlations with El Nino
- droughts
- strong hurricanes
- heavy percipitation
Atlantic hurricane season ____ during El Nino
weakens
what are 5 global circulation patterns
- polar high
- subpolar low
- subtropical high
- ITCZ
- Hadley cell
what front is represented with blue triangles
cold fronts
what front gets more violent weather
cold fronts
when do we see fronts in Lethbridge
winter (don’t have many in summer - not many lP systems)
what are surface currents impacted by
wind and Coriolis force
is there a layer in the ocean that does NOT interact with the wind
YES- the deeper you go
where are the five main gyres
2 in Atlatic and Pacific
1 in the Indian
western intensification on western side has water come from
nN to S
in downwelling how does the water get warmer
with depth
upwelling or downwelling is nutrients rich
upwelling
salinity
concentration of dissolved solids (
average salinity is
3.5%
what happens to salt as ocean water evaporates
it is left behind and increases salinity
where is salinity the highest
at the equator
why is salinity highest at the equator
most dense
brine
has high evaporation = very salty
brackish
mix of ocean and freshwater with freshwater inputs
what drives thermohaline
salinity and temp (density)
where is the most dense water found
Greenland
