Ch 19 - Tropical Revloving Storms Flashcards
Factors that a TRS needs to form
Coriolis - Gives us the rotation
Moisture - A lot of moisture to fuel the TRS
Warm seas - Over 26.5C (and deep)
The role of the Equatorial Low Pressure Belt
Has the maximum heating as it is the Heat equator ITCZ
Low pressure than means air is rising leaving low pressure on the surface
Depends on the land/sea masses and the season
TRS originate on the ITCZ
Easterly Waves (July)
When the equatorial low pressure belt is mixing with the Azores high in the south Atlantic
Storms develop and develop into a TRS if conditions are right (account for 80% of the storms that hit the US)
The ITCZ = low pressure which rotates anticlockwise which is why there is easterly airflow
Azores high (clockwise) mixes with ITCZ which forms; troughs of low pressure, convective activity which leads to storms/TS developing which impact N. America. Can develop on mainland Africa where there are lots of TS which then feed this system.
Hurricane Season in the US
Fed from the easterly waves in July/ August/ September
Can be as many as a couple of waves a week
~1 in a 100 turn into a TRS
Hence the uk gets the tail end of storms
Mesoscale Convective Systems/Areas (MCAs)
Groups or clusters of Cu/Cb which form on equatorial lows
Can be 100-1000km long and can last for 1-2 days
Can form multi-cell TS
Regions Affected by TRS
N America
China
NE Pacific
N India
Madagascar
W Australia
N Australia
Northern Hemisphere TRS Season
June to October
Southern Hemisphere TRS Season
January to march
N. Atlantic
Hurricanes
10-12 a year
N.E Australia
Cyclones
9 Per season
S. China Sea
Typhoons
25
N. E. Pacific
Hurricanes
16/17
N India
Cyclones
5/6
Madagascar
Cyclones
10/11
W. Australia
Cyclones
7
