Climatology Flashcards
High Pressure
Subsiding air(descending), anticlockwise in rotation in S hemisphere
Low Pressure
Rising air, clockwise in rotation in S hemisphere
Coriolis force
Deflection of wind and ocean currents as result of world spinning. Deflection left in SH and right in NH
Doldrums
place of zero hzontal air flow. Associated with equator(ITCZ)
ITCZ
Inter Tropical Convergence Zone. Band of LP’s as a result of perpendicular heating from sun
Advection
hzontal movement of air in atmosphere
Convection
LP currents(vertical) resulting from suns heating
PGF always moves from …
High to low
Relationship between geostrophic flow and isobars?
Geostrophic flow is always parallel to the isobars
Isobars
lines of eql psi
Primary circulation(vertical) cells
Hadley(0-30°)
Ferrell(30-60°)
Polar(60-90°)
4 main psi cells
Equatorial low (equator 0°)
Sub-tropical high (30°)
Sub-polar low (60°)
Polar high (90°)
Pressure cell characteristics
Equatorial LP - thundershowers due to convection
Subpolar LP - Cold fronts/rainfall
All HP - Descending air, deserts + clear skies
Secondary Circulation(hzontal)
Tropical easterly (trade winds) 5-30
Westerly wind belt 30- 60
Polar easterly wind belt 60-90
Atmospheric Circulation
Distributes thermal ene over earth surface
Atmospheric psi
force per unit area exerted over earth
How are HP’s formed?
When air go down at surface
Pressure Gradient strength
Depends on distance of isobars - further isobars = weak pressure gradient and vice versa.
PGF
Force acting on atmosphere as result of pressure gradient. Moves air from HP to LP also makes speed of wind. eg strong PGF = higher wind speed.
Monsoon Winds
Seasonal reversal of atmos psi and winds
Fohn Winds
Dry hot winds where there are significant changes in altitude(eg mountainous area)
DALR
Dry Adiabatic Lapse Rate
SALR or WALR
Saturated Adiabatic Lapse Rate or Wet Adiabatic Lapse Rate. Both the same thing
