dominated between clash of cold polar air and warm subtropical masses
along the front are warm
air waves with a following
cold front
due to Coriolis
force they can turn
into a depression
Life span of 4-7 days covering 15,00-3000km diameter
key feature - both warm and cold front can bring rain
warm air has more moisture, chilled by the cold air it forms clouds and then rain
High-pressure systems
warm subtropical high pressure systems bring clear skies and sunny weather
Coriolis force means these light winds
(associated with high pressure
systems) move clockwise in northern
hemisphere and thus oppose easterly
velocity of the frontal system
Thus, acting as a blocking system that can last many days
Tropical
Inter-tropical convergence zone
ITCZ dominates tropical weather
This is where trade wind systems of both hemispheres converge due to the Coriolis force.
forms because of the intense solar heating of the tropics
and mass evaporation causes air with moisture to rise, the
low pressure causes it to cool reducing its ability to hold water and thus form clouds.
This is why the tropics have huge towering
columns of clouds which produce very intense
convectional rainfall
Monsoons
derived from the Arabic word 'mausim' meaning season
Most of the rain in southeast Asia falls in summer
As winds are always defined by the
direction from which they are coming
one can tell where the monsoon
originates e.g. the southwest
monsoons start there and move
towards the northeast etc
In summer the intense heating of Asia causes air to
rise which lowers air pressures allow winds from the
south to be sucked in from across the equator.
This creates the opposite effect of the Coriolis
force in the northern hem changing direction by
over 90 degrees resulting the southwest
monsoons.
these winds are warm and by
travelling across the indian and
pacific oceans they contain a
lot of moisture.
As they pass over land they are forced to rise causing them to cool and give their moisture up in the form of torrential rain - the monsoons.