Pressure Gradients & Wind Patterns Flashcards
Monsoons result because of
Differential heating of the land and ocean.
Monsoons: a wind that
Persists in a particular direction and changes with a change of season (often reverses).
Trade winds: (4)
Flow from subtropical anticyclones.
Warm and humid.
Blow towards to equator in both hemispheres.
Feed to ITCZ with large amounts of very warm and humid air and water evaporated from the oceans; this supplies the ITCZ with massive rainfalls.
ITCZ: (4)
Occurs over low latitudes.
Near to the equator.
Line of deep cumulus cloud.
Migrates south during January towards heated continents.
ITCZ: the speed of trade winds declines as
They move towards the ITCZ, can be from 15 knots down to 5 knots.
ITCZ: Air, from the trades, ascends at the ITCZ, because the air is very
Moist, it results in precipitation along most of the length of the ITCZ.
At some locations along the ITCZ, the sea surface temperature is too cool for
The formation of deep cumulus cloud, therefore there is no precipitation.
Eg the Eastern Pacific is relatively cool.
Horizontal pressure gradient: barometric pressure
Decreases upwards;
At sea level it is relatively weak, may be 7 hPa over 45’ latitude, whereas at 2000m altitude, may be much stronger at 32 hPa over 45’ latitude.
Horizontal pressure gradient: steeper =
Greater force down the gradient from high to low pressure.
Horizontal pressure gradient: developed because of
Horizontal thermal contrast in the troposphere.
Horizontal pressure gradient: Temperature gradient with colder air towards the poles can force a wind to blow, therefore
There is an increase in wind speed with height in a frontal zone.
Horizontal pressure gradient: if front is W-E (temp gradient is N-S) then the
Wind will increase from the west.
