The atmosphere Flashcards
Incoming radiation is…
short wave
in the tropics there is a A ___ of heat and a B___ in the poles
A-Surplus B- Deficit
Factors influencing surface temperature
angle of incidence thickness of the atmosphere colour of surface altitude ocean currents
Air moves from…
High to low pressure areas
the closer the isobars, the ___ the pressure gradient
steeper
Gradient pressure force
Force affecting wind speed NOT wind direction
Coriolis force/effect
Any moving body is deflected by Coriolis force
Deflects left in S hemisphere
Deflects right in N hemisphere
Geostrophic flow
When Coriolis force and pressure gradient force move in opposite directions. Results in wind blowing parallel to isobars
Low pressure cells
Air cools as it rises
rotates clockwise
air sucked in at surface
associated with clouds and rain
High pressure cells
air warms as it sinks
air is repelled at the surface
air rotates anticlockwise
associated with calm, cloudless conditions
Factors affecting the formation of seasons
sphericity rotation tilt of the earth's axis revolution Axial parallelism
Summer solstice in S hemisphere
21 Dec
Temperature will increase and decrease as ___ does
Pressure
Explain the formation of a sea breeze
The land is heated and the sea remains cool
Hot air rises from the land resulting in a low pressure
Air over the sea has a higher pressure
Air moves from high pressure to low pressure
Sea breeze is formed
Hadley cell
circulation between equator and 30 latitude
Ferrel cell
circulation between Hadley and Polar cells
Polar cells
Circulation towards LP polar belt at 60 N & S
Air masses
bodies of air with the same temperature and moisture characteristics
Maritime
Moist air over the ocean
Continental
Dry Air over the continent
Tropical air is (a) and Polar is (b)
a) warm b) cold
Monsoon winds
seasonal reversal of atmospheric pressure, winds and rainfall
Caused by shift in pressure belts with the sun and ITCZ
ITCZ
Inter tropical convergence zone
DALR
Dry adiabatic lapse rate
air cools -1 as rises
air heats +1 as it sinks
WALR
Wet adiabatic lapse rate
Air is saturated so cools -0.5 as rises
Fohn winds
general name for a hot, dry wind that originates in a mountainous region
Jet streams
Strong winds blowing W to E in the upper atmosphere
Can reach very high speeds
El Nino
- -warm water flows from W to E pacific (reverses)
- -HP develops over Indonesia
- -Descending air warms and dries conditions over the sea
- -Heavy rain occurs over S America
La Nina
- -Normal LP over Indonesia drops even lower and HP over pacific ocean becomes even higher
- -Causes higher than usual rainfall in Indonesia, drought in S America
Effects of El Nino
Forest fires in Indonesia (now dry conditions)
Flooding in Peru
Reduction in upwelling of cold water= less fishing
What is a drought
an extended period of a deficit of rainfall relative to the area’s average
Types of drought
Meteorological
Agricultural
Hydrological
Socio-economic
Causes of drought
- excessive heat build up over the earth’s surface
- winds carrying continental air masses instead of oceanic ones
Effects of drought
- decrease in tourism
- crop failure
- threatened ecosystems
- bushfires
Desertification
The process of land degradation in semi-arid areas resulting from climate change and human activities
Human activities causing desertification
- overgrazing
- surface mining
- increasing population and poor planning
