Tropical Cyclones

1
Tropical Cyclones aka Hurricanes
Art Institute of Seattle, 22 May 2009
2
Where do tropical cyclones occur?
3
Sea Surface Temperature
Equator
TCs form over warm water
4
Locations of Tropical Cyclone Formation
TCs form near but not on the equator
5
Typical Tropical Cyclone Tracks
Note that hurricane, typhoon, and cyclone
are local names for the same thing
6
Many hurricanes form over eastern Atlantic when
easterly waves move off Africa and help
convection in the ITCZ turn into hurricanes
7
Tropical Cyclone Structure
8
Hurricane Katrina
9
Definition of a Hurricane
10
More Definitions
11
Flying in Hurricanes
12
To see whats going on under the upper-level
cloud, need radar observations NOAA WP-3D
Hurricane Hunter Aircraft
13
Hurricane aircraft instruments
14
Preparing a dropsonde for launch
15
Ready to launch a dropsonde
16
Hurricane Katrina
Where should the plane go exactly?
17
Communications during a hurricane aircraft mission
Boulder
Tampa
Miami
18
In Miami
19
Hurricane Katrina--seen from space
How does this look from an airplane flying in the
eye of the storm? Note the slope of the eyewall
20
Inside the eye of Hurricane Rita (2005)
21
Inside the eye of Hurricane Katrina (2005)
Note the slope of the eyewall
22
(No Transcript)
23
Hurricane Katrina
What does it look like under all those
clouds?
24
To see whats going on under the upper-level
cloud, need radar observations NOAA WP-3D
Hurricane Hunter Aircraft
25
(No Transcript)
26
Hurricane Andrew approaching and moving over
Miami --movie loop of Miami radar observations
27
Idealized radar view of a hurricane
rainband
28
Sketch of Mature Hurricane Structure Vertical
cross section along AB in previous slide
Note that the storm is a high aloft and a low at
low levels Note the slope of the eyewall
A
B
29
Top of a Tropical Cyclone Upper-level cloud,
wind, pressure
cirrus cloud
eye
30
Satellite photo of the top of a tropical cyclone
High clouds swirling outward
31
High level clouds spiral anticyclonically
outwardLow-level clouds spiral cyclonically
inward
32
Tropical Cyclone Damage
33
Types of Hurricane Damage
Wind
Heavy Rain/Floods
Storm surge
Tornadoes
34
Saffir-Simpson Scale for Hurricane Strength
Category Max sustained wind speed Max sustained wind speed Max sustained wind speed
Category mph knots damage
1 74-95 64-82 Tree damage, small boats torn from moorings, roads flooded
2 96-110 83-95 Roofing, windows, doors boats, piers, mobile homes
3 111-130 96-113 Some structural damage to buildings, flooding, wave damage
4 131-155 114-135 Lots of structural damage, major flooding, storm surge
5 156 136 Catastrophic, building failures
35
Category 1 Miami 2005
36
The Great Galveston Hurricane
Cat 4
Cat 3
Cat 0
37
Category 4 Damage Galveston 1900
38
(No Transcript)
39
Note Category 5 is rare
40
Storm Surge
41
Types of Hurricane Damage
Storm surge
42
Types of Hurricane Damage
Storm surge
43
(No Transcript)
44
Hurricane Forecasting
45
Important factors that make ahurricane develop
Warm ocean--hurricanes get their energy from the
ocean Humid atmosphere--need high humidity to
get clouds to develop Weak wind shear --if
wind is stronger at upper levels than lower
levels, storm top separates from lower part of
storm
46
Forecasting Hurricane Rita (2005)
47
Map of ocean heat content
48
Satellite view of humidity
Clouds
Moist air
Dry air
Dry
49
Map of wind shear
Very low wind shear
50
Map of steering winds
51
Model forecasts of Ritas storm track
52
Numerical Model Simulation of Rita
53
End