Transcript Lab 8

Lab 8
November 6th, 2013
Hurricane Review
 Winds rotate counter-clockwise around the center
 Storm surge is caused by the wind; a wind-driven rush of sea into coastal
areas as a strong tropical cyclone arrives
 Greater wind velocity results in stronger storm surge
Southern Hemisphere?
 Remember, Coriolis deflects the wind to the left. How
does that affect wind flow around lows and highs?
Hurricane
Formation/Intensification
 Hurricanes thrive off of warm, moist air (this is why
they tend to form over water near the equator!)
 Intensification occurs when the hurricane continues to
feed on the energy from these warm waters
 Oftentimes, the wind from a slow moving cyclone
agitates surface of the ocean , bringing deeper water to
the surface, analogous to upwelling
 How does this affect the ocean temperature, and thus
the storm’s intensification?
Convergence/Divergence
 Convergence = air coming together
 Surface convergence is associated with surface lows
L
 Divergence = air moving away
 Surface divergence is associated with surface highs
H
Surface – Upper Air
Interaction
• Surface pressure is proportional to the
weight of the column of air above
• Decreasing weight leads to strengthening
surface lows, increasing weight leads to
strengthening surface highs
Decreasing column weight
Decreasing column weight
L
H
Advection
 Transport of a quantity by the wind
 Often interested in temperature advection
 Depends on:
 Strength of the wind
 Angle that the wind crosses isotherms
 Temperature gradient
Reading Wind Barbs
Credit: http://nycmetnet.ccny.cuny.edu
Advection - Example
30 nm
20
30
0 nm
40
50
60
 What will the temperature be in one hour? Hint: 1 knot = 1
nautical mile.

In 1 hour, the isotherm pattern will be advected 30 nm to the south.

Just look at the temperature 30 nm to the North, 20 degrees!
Fronts
 When defining fronts, cold air calls the shots
 Cold Front = Cold air advancing
 Warm Front = Cold air retreating
 How do we locate fronts?
 Temp gradient  located at leading edge of cold air
 Wind directions  located where wind directions
change abruptly
 Surface pressure  located in a trough of low pressure
Cold Front Placement
Lab Assignment
11.1 (b)
11.13
12.10 (a, b, c, d)
12.11 (a, b)
13.1 (a, b)
13.2 (a, c)
13.7 (a, b)
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