EPSC 185 Lecture Notes - Lecture 3: Indian Ocean, Tropopause, Landfall
23 Jun 2018
School
Department
Course
Professor
We study the phenomena from a scientific point of view
Psychological and emotional impacts on people who lose everything they have - must relocate
to somewhere where they are not welcomed, they are deprived.
Hurricanes - like open water
Hurricane Mitch - occurred in late October early November, impacted central America, classified
as a sector 5 hurricane
Why do we care?
High winds
Heavy rains
Injuries and loss of life (drowning)
Economic losses
The western countries (the developed world) suffer with loss with money (economy) and the
vulnerable countries suffer with loss of life
Why Bangladesh ?
Vulnerability
Located adjacent to a very warm body of water
Extremely populated area of the world
Worlds deadliest tropical cyclones:
Deadliest storm in the atlantic basin - 1780 (22,000)
Deadliest Us storm (Gavelston hurricane) - 1900 (8,000)
Of the 10 deadliest US storms in the US
One has occurred since 1957
Katrina (2005) 1833 dead
Economic impacts:
The most obvious economic impact is the rebuilding of damaged infrastructure
However, other costs that are less often considered include:
The cost of evacuation
The impact on energy production
The cost of severe coastal erosion
Four most expensive US hurricanes:
Katrina, Sandy, Andrew and Ike
Hurricane
1) Warm core, low pressure system
2) No “fronts” attached
3) Develops over the tropical or subtropical waters
4) Has an organized circulation with winds of at least 120 km per h (74 miles per h, or 63
knots)
What do we mean by warm core?
1- Warm moist air moves over the ocean
2- Water vapour rises into the atmosphere
3- As the water vapour rises, it cools and condenses into liquid droplets
4- Condensation releases heat into the atmosphere making the air lighter
5- The warmed air continues to rise with moist air from the ocean taking its place
creating more wind
Tropopause: Another mechanism of warming in the tropical cyclone’s centre is subsidence. As
the air in the eye of the cyclone sinks, it warms due to compression
Tropical cyclones (TCs) always originate over the tropical oceans (in maritime tropical air
masses)
Hurricanes are used to describe TCs that occur over the Atlantic and the eastern pacific ocean
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