Atmosphere

Question 1

explain the surplus/deficit of energy at equator/poles

Answer 1

• high albedo at poles/low albedo at equator
• more atmsphr to pass thru at poles bc curve = more likely to be reflected by clouds
• no winter solistice so sun always at equator, 24hr darkness at poles
• sun more conc at equator bc insolation is greatest where rays vertically hit
• suns angle in sky decreases towards pole bc curve = heat energy spread over larger surface
• tilt of axis means sun higher in tropics thru year, focusing energy

Question 2

account for insolation reaching earths surface

Answer 2

• 46% absorbed by earth’s surface
• 17% reflected by clouds, 88% by gas particles
• 6% reflected by light surfaces (eg ice) on earth
• 23% absorbed by clouds, dust, water vapour etc

Question 3

describe atmospheric circulation cells & trade winds in the northern hemisphere

Answer 3

• hadley formed 0 - 30N & thermally direct
• trade winds move SW towards equator
• ferrel formed 30N - 60N & thermally indirect
• westerly winds complete cell and take air NE
• polar cell - air sinks at poles & movess from 60N to 90N
• polar easterlies take cold air south
• warm air from equator moved to higher latitudes
• cold air from poles move to lower latitudes

Question 4

explain energy redistribution

Answer 4

• winds deflected right bc coriolis effect
• winds move from high to low pressure
• air forced to rie at equator bc heat & convection currents
• air sinks at poles bc cool
• cells and winds transfer surplus energy to deficit

Question 5

oceanic circulation in N hemisphere: atlantic

Answer 5

• in n hemisphere, a gyre is formed
• C effect deflects ocean current to right in n hemisphere
• land mass of americas deflects ocean currents towards the caribbean sea
• north equatorial current pushes surface water westwards, until obstruction via land masses pushes water north]
• SW winds push gulf stream NE towards europe as north atlantic drift
• currents like north atlantic drift carry warm waters to cooler latitudes
• cold waters move south from poles via Labrador Current
• this is a deepwater current bc water is denser at poles bc salinity and temp

Question 6

explain pattern of rainfall in W africa

Answer 6

• dependent on movement of ITCZ, meeting point of cT & mT air masses
• ITCZ = zpne of convergence btw warm, wet, low p, unstable mT & hot, dry, high p, stable cT
• warm, moist air forces to rise, colling & condensing into clouds = low pressure
• ITCZ migrates N to S throughout yr w/ passage of overhead sun, thermal equator
• as it moves N to position overhead the tropic of cancer, it brings associated band of rainfall w/it = rainy season Apr-Oct