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)
Office hours Thursday’s from 6-7 pm in Wx Center