chapter 6: atmospheric circulation

controls on direction of airflow

- unequal heating of surfaces -pressure gradient force -Coriolis effect -frictional forces

Upper air cells

-Hadley cells -ferrel cells -polar cells

persistent pressure systems:

-ITCZ -STH (25-30 degrees N and S) -subsolar low (front) (60 degrees N and S) -polar high (90 degrees N and S)

how do high pressure systems dictate wind patterns?

-low pressure goes up -high to low because it tries to balance air pressure equal around earth

The bottoms of the cells create surface winds, which are deflected by the Coriolis effect

-northeast trade winds (0-30 degrees N) and southeast trade winds (0-30 degrees S) -westerlies (30-60 degrees N and S) -(polar) easterlies (60-90 degrees N and S)

3 motions of air around pressure systems

1) vertical 2) horizontal 3) circular

This force is created by Earth's rotation and causes the ______ The Earth is always spinning underneath objects that are floating/flying above it Your perspective (Northern or Southern hemisphere) determines the direction of deflection: Causes deflection to the right in the northern hemisphere Causes deflection to the left in the southern hemisphere

Coriolis effect

Trade winds at the bottom of these cells 0-30 degrees N and S circulation between the STH and ITCZ creates a cell known as the _____ this cell contains the whole area where air rises at the ITCZ and sinks at the STH

Hadley cell

-_____ is a region of low pressure systems circling the planet near the equator -shifts up and down moving all of the other pressure cells and surface winds with it -the area of the planet receives the most insolation (and heat), causing air to rise (which promotes strominess) because air flows into low pressure, the northeast and southeast ______ (surface winds) flow into the ITCZ

ITCZ (equator); trade winds

how does earths rotation cause the Coriolis effect

The Coriolis effect makes storms swirl clockwise in the Southern hemisphere and counterclockwise in the Northern Hemisphere. A force that explains the paths of objects on rotating bodies

-clockwise around high pressure and counterclockwise around low pressure in the northern hemisphere -counterclockwise around high pressure and clockwise around low pressure in the southern hemisphere

circular

____ is a change in ocean circulation I t involves a reversal of "normal" flow in the Pacific. The Southern Pacific is usually under the influence of the southeast trade winds (So cold water upwelling by South America is brought to Australia and Oceania) During this, the winds weaken and the warmer water stays by South America. This is a huge topic and I'm barely touching it. However, it's a great example of how one small component of the Earth's circulation system being altered can cause changes around the planet.

el nino

The upper air wind cell in the middle latitudes is the ______ the bottom of this cell creates the primary surface winds of the middle latitudes- the _____ distinct changes between the cold polar air and the warm tropical air cause a very fast upper atmospheric wind-the subsolar jet stream 30-60 degrees N and S

ferrel cell; westerlies

one very important part of this circulation is the warm ____ current

gulf stream

ocean water patterns often form large loops known as ______ that help mix large bodies of water These cells are important for oceanic life and help to regulate the temperature of water globally. The Coriolis effect which impacts surface winds is also responsible for these While winds can travel the world (relatively) freely, ocean currents are trapped and shaped by landmasses

gyres

clockwise circular pattern (in northern hemisphere), winds move down and away, associated with fair skies

high pressure

air flows away from high pressure and flows into low pressure (advection)

horizontal

_____ are like "rivers of air" in the upper troposphere- they are very important for guiding storms (low pressure systems) from west to east across the mid/mid-high latitudes

jet streams

counterclockwise circular pattern (in northern hemisphere), winds move up and into center, associated with storminess

low pressure

the subpolar jet stream moves north/south (along meridians) throughout much of its path

merdional flow

60-90 degrees N and S bottom of the cell is easterlies/polar easterlies the easterlies are the surface level winds caused by the upper air wind patterns known as the _____

polar cell

At around 90˚, the air is very cold and sinks at the ____ This air pushes toward the subpolar low once it descends and disperses. The air pushing south is deflected and the Polar Easterlies are the result. The easterlies are the surface level winds caused by the upper air wind pattern known as the Polar Cell.

polar high (90 degrees N and S)

a _____ exists between the center of a low pressure system and the center of a high pressure system

pressure gradient force

_____ can shape the path of the subsolar jet stream, allowing tropical air to surge poleward or arctic air to plunge toward more tropical areas this causes a major driving force of temperture difference between the poles and tropics our strange shifts in fall and spring weather are determined by these and their impact on the subsolar jet streams

rossby waves

two major jet streams

subpolar and subtropical

Some of the air pushed down by the STH goes back to the ITCZ, but some of it also continues poleward to mid-latitude locations the higher latitude (around 60 degrees) are impacted by the ____ (known as polar front) The polar lows are associated with the subsolar jet streams and causes much of our wher here in North America (bringing cold Canadian air together with moist Gulf of Mexico air)

subpolar lows (60 degrees N and S)

Air from the ITCZ rises and moves poleward as it cools in the upper atmosphere (advection moves the air away to both the north and the south) As this air moves closer to the poles, it gets cold enough to sink back to the surface this happens around 25-30 degrees latitude, creating a band of consistent high pressure called _____ these latitudes basically have perpetual high pressure

subtropical high (STH) 25-30 degrees N and S

vertical currents in the ocean are the result of salinity and temperature and creates a world-wide movement of water called the _____ (or oceanic conveyor belt)

thermohaline circulation

air rises at the center of low pressure and sinks at the center of high pressure

vertical

the subpolar jet stream moves west to eats with few deviations

zonal flow