Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
58 Cards in this Set
- Front
- Back
|
There are ... pressure belts. Why do they occur? |
-4
-different places being heated differently -shift with the seasons |
|
|
What are the 4 pressure BELTS? |
1.equatorial low pressure belt (Equator) 2.subtropical high pressure belt 3.sub polar low pressure belt 4.polar high pressure belt |
|
|
What are the characteristics of the Equatorial low pressure belt? |
-low pressure -calm doldrum winds only move vertically -warm air rises/lighter/expands
|
|
|
What are the characteristics of the Subtropical high pressure belt? |
-high pressure -found either side of the equator 30-35 degrees N/S -air rises & cools with with alitude -air pushed towards poles -becomes heavy/sinks = high pressure -dry/clear skies/cloud free -anticyclones |
|
|
What are the characteristics of the Sub-polar low pressure belt? |
-low pressure -60-65 degrees N/S -air rising -depressions
|
|
|
What are the characteristics of the Polar high pressure belt? |
-high pressure -air is cooled/denser |
|
|
Winds always blow from an area of... pressure to an area of... pressure |
high
low |
|
|
What are the characteristics of the North-east/ South-east Trade winds? |
-Blow from Subtropical high pressure belt to Equatorial low pressure belt -permanent and regular -on journey to equator saturated with moisture - heavy rainfall near equator yearly
deflected by Coriolis effect as they blow from: -north east direction in Northern hemisphere -south east direction in Southern hemisphere |
|
|
What are the characteristics of the North/ South Westerlies? |
-blow from Subtropical high pressure belt to Sub polar low pressure belt -blow from a westward direction -not as strong/regular as trade winds -stronger in southern hem = wide expanse of water -swing N/S annually
deflected by Coriolis effect as they blow from: -south west direction in Northern hemisphere -north west direction in Southern hemisphere |
|
|
What are the characteristics of the Polar Easterlies? |
-blow from Polar high pressure belt to Sub polar low pressure belt -Northern hem local seasonal changes = blow in several directions -Southern hem = very regular -contact with ice sheets = cold & dry -collision w westerlies = cyclones & weather changes & heavy precipitation
deflected by Coriolis effect as they blow from: -north east direction in Northern hemisphere -south east direction in Southern hemisphere |
|
|
Describe the structure of the Earth in relation to the Major Pressure Belts and Planetary Surface Winds:
(diagram) |
|
|
|
What are Rossby Waves? |
-high altitude -westerly winds -follow an irregular path -path changes with the seasons -jet streams are found within Rossby waves |
|
|
What are Jet streams? |
-seperate cold and warm air -pull along weather fronts -found just blow tropopause -narrow fast moving belt of air |
|
|
What is the cause of Jet streams? |
-large difference in temperature gradient between two air masses -pressure differences between north/south air masses |
|
|
What are the two types of Jet streams? |
-the Polar front jet stream (PFJS) -the Sub-tropical jet stream (STJS) |
|
|
What is the PFJS (Jet stream)? |
-westerly band of wind -where cold polar & warm tropical air meet over the Atlantic ocean -pilots ride in it west to east avoid it east to west -latitudes 40/60 degrees -marks division of Polar/Ferrel cells -helps explain formation of mid latitude weather systems like depressions |
|
|
What is the STJS (Jet stream)? |
-westerly -25-35 degrees N/S -associated with pole-ward end of Hadley cell -in summer shifts over west Africa and India = may become easterly = warmer temps over land than southerly seas
|
|
|
Where about are the two Jet streams located? |
jet streams |
|
|
Define: The Tri-cellular Model |
-explains differences in pressure belts, temperature & precipitation globally -makes sure not a surplus of energy at the equator and deficit at the poles |
|
|
What is the purpose of the Hadley Cells and where are they located? |
-2 cells N/S equator -responsible for; tropical air circulation & seasonal changes in climate -regions with a wet and dry climate -between the two Hadley cells is the ITCZ with doldrums |
|
|
How does the Hadley Cell work? |
-rising limb N/S equator rising air -30 N/S falling limb air begins to warm & sink -30 N/S = high pressure at surface = cloudless skies & subtropical anticyclones -air is then sent back to equator as trade winds to help form the ITCZ -or sent pole wards due to deflection by Coriolis effect
|
|
|
How does the Ferrel Cell work? |
-2 cells 30-60 N/S -responsible for; climate types in mid-latitudes -air from hadley cell at ground level pulled towards the poles -warm westerly winds within ferrel cell pick up moisture from oceans -winds meet cold air from poles -warm tropic air rises over cold air = less dense -uplift of air = low pressure at g.l -unstable conditions = depressions -air either returns to tropics/polewards |
|
|
How does the Polar cell work? |
-2 cells 60-90 N/S -at surface of poles, descending air = high pressure -winds move from high pressure near poles towards low pressure ferrel cell (sub-polar belt) at 60 degrees -prevailing winds defected right in n.hem. left in s.hem. -warm air is brought into polar cell where it meets ferrel cell at ground level = helps to address energy deficit |
|
|
What is the purpose of Ocean Currents? |
-redistribute energy -make sure low latitudes dont become too hot -make sure high latitudes dont become too cold |
|
|
What sets up convection currents within the ocean? |
-uneven heating of surface water -high and low latitudes -transfer energy
|
|
|
Where is water most dense and why? |
-around the poles -contains more salt |
|
|
Dense water flows... into... surface currents head... from... |
-downhill -deep ocean basins -pole-wards -equatorial Atlantic ocean |
|
|
How are ocean currents set in motion? |
-frictional drag from prevailing winds -ocean currents follow wind direction -direction also influenced by Coriolis effect (right in north, left in south) |
|
|
Why does each ocean have it own circular pattern of currents & what are they called? |
-produced as one mass of water moves from one climatic zone to another -gyres |
|
|
Where are ocean currents most dominant? |
-western sides of ocean basins |
|
|
What is the influence of the North Atlantic drift? |
-Atlantic ocean -high to low latitudes -influence dominant in winter between 40-65 degrees N/S -prevailing westerlies blow on west sides of continents = warming influence |
|
|
What is the influence of cold ocean currents? |
-less of an effect on temps -except Labrador current off east coast N.America/E.Canada -brings freezing conditions/ice |
|
|
Where is the intensity of solar radiation greatest? |
-low latitudes - equatorial low pressure belt |
|
|
Equatorial areas receive less insolation than tropical deserts - why? |
-ITCZ cloud cover |
|
|
Small seasonal variations in temperature in equatorial areas but larger in middle & high latitudes - why? |
-less variation in suns angle in the sky |
|
|
Small seasonal variation in daylight hours in equatorial areas but larger in middle & high latitudes - why? |
-due to earths tilt equator faces sun for the longest period |
|
|
In terms of altitude, what can modify temperature & precipitation? |
-ELR -hills, mountains cooler than surrounding lowlands -lower temps increase amount and frequency of precipitation |
|
|
What is the process that forms clouds & precipitation in places of higher altitude i.e. mountains? |
-air mass cools as uplifted over hill/mountain -expands as pressure falls with height -cools further -reaches dew point -condenses forming clouds = precipitation |
|
|
What is the rain shadow effect? |
-leeward side warmer & drier than windward side -air warms as it descends from high to low levels -clouds evaporate -reduced probability of precipitation |
|
|
What is the latitude of the UK? |
between 50-60 degrees northern hemisphere |
|
|
Describe the locational setting of the UK: |
-oceanic location -north western edge of Europe -exposed to prevailing onshore westerly winds -influenced by north Atlantic drift warm ocean current |
|
|
Outline the temperature of the UK in July and why: |
-temperatures reach peak in southern regions -decrease towards north -reduction in isolation at higher latitudes |
|
|
Why do regions in the UK furthest away from the sea have the highest temperatures? |
sea has less of a cooling influence on the land |
|
|
How does the altitude of UK land affect temperatures? |
-southern uplands of Scotland cooler than northerly central valley area between Glasgow & Edinburgh |
|
|
What is the Gulf stream? |
warm current starts in Gulf of Mexico and travels along east US coast then crosses North Atlantic ocean |
|
|
What affect do prevailing winds & ocean currents have on the UK? |
-higher winter temps on west coast of UK -warmer air associated with north Atlantic drift -gulf stream waters to west of British Isles |
|
|
Why is the west of the UK prone to precipitation? |
-southwesterly winds from over the ocean picking up moisture -rises, cools, condenses -hits upland areas - rains |
|
|
What is the main warming influence in July? |
-overhead sun |
|
|
What is the main warming influence in January? |
-Gulf stream |
|
|
Precipitation is highest in the north & west because... |
-rain bearing air masses/frontal systems track eastward -shed moisture as rainfall -air masses warm become less humid as they move inland |
|
|
The east side of the UK is lowland, how does this affect precipitation occurance? |
-less -rain shadow of west side |
|
|
What is likely to happen in a UK summer, the driest season? |
-anticylones blocking approaching fronts & deflecting them |
|
|
What does winds having a 'large fetch' mean? |
the wind has travelled a long way |
|
|
What direction do the prevailing winds come from when blowing on the UK? |
south west |
|
|
When do long spells of easterly winds occur in the UK? |
in winter bringing dry weather |
|
|
Where are the strongest winds in the UK? |
-north/west -face south westerly winds |
|
|
Upland areas experience strong/gale force winds as... |
air has few obstructions/less friciton |
|
|
Wind increases with height but strongest over summits of hills and mountains for example... |
Great DunFell in Cumbria |
