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Weather in a Tank: Exploiting laboratory experiments in the teaching of
meteorology, oceanography, and climate
Brian TangJohn MarshallLodovica Illari
Teaching rotating fluid dynamics to a broad audience
THE CHALLENGE
Creating a learning environment where students are encouraged to learn through investigation and inquiry
A combination of approaches is needed
Theory
THE CHALLENGE
Φ−∇=×uzfr
ˆ
Observations Models & Experiments
?
Models & Experiments
THE CHALLENGE
Propose using simple laboratory tank experiments as a key part of the education of students
METHODOLOGY: EQUIPMENT
Dye Stir BalancedMotion
Solid BodyRotation
PROJECTS
EkmanLayersFronts General
Circulation Convection
Density Currents Ekman Pumping/SuctionTaylor Columns
PROJECTS
Thermohaline CirculationOcean Gyres Source/Sink Flow
PROJECTS
Potent Potables
METHODOLOGY: IMPLEMENTATION
INSTRUCTOR STUDENTSDescribe premise of experiment
Make prediction of experimentDemo experimentHighlight relevant theory
Perform experimentAnalyze real world observationsReports and presentations
Connect the dots
EXAMPLE: FRONTS
1. Describe premise of experiment• What is the polar front?• What is the cause of the jet stream?
ΩΩ
FRESH WATER
FRESH WATER
DYEDSALTY WATER
2. Make prediction of experimentWhat they think they will observe in the rotating frame of reference for combinations of Ω and ∆ρ.
Ω=0∆ρ=0
Ω=large∆ρ=0
EXAMPLE: FRONTS
ΩΩ
∆ρ=0 ∆ρ=0
Ω=0∆ρ=large
Ω=large∆ρ=large
ρ1 ρ2
12 ρρρ −=∆
∆ρ
Ω=0∆ρ=0
Ω=large∆ρ=0
x o
No rotation is fairly intuitive. Once rotation enters the mix, get some interesting responses.
EXAMPLE: FRONTS
Ω=0∆ρ=large
Ω=large∆ρ=large
x
ox
o
EXAMPLE: FRONTS
3. Demo experimentDome of salty water. Cyclonic motion at surface.
4. Highlight relevant theory
• Margules’ Equation
EXAMPLE: FRONTS
fgvv
γρ
ρρ tan
2
1212
−=−
• Thermal Wind Equationfρ2
Tzfp
R
z
u g ∇×−=∂∂
ˆr
EXAMPLE: FRONTS
5. Perform experimentCollect data to validate Margules’ Equation
fgvv
γρ
ρρ tan
2
1212
−=−
EXAMPLE: FRONTS
5. Analyze real world observationsX-section across polar front to validate Thermal Wind
pressure
70N 20NN S
pressure
Potential temperature and zonal wind
Finally, connect the dots!Theory
EXAMPLE: FRONTS
fgvv
γρ
ρρ tan
2
1212
−=−Tz
fp
R
z
u g ∇×−=∂∂
ˆr
Observations Model
MID-LATITUDE GENERAL CIRCULATION DEMO
MID-LATITUDE GENERAL CIRCULATION DEMO
Theory
Observations Model
[ ]dpTvg
caH p ∫ ′′= ϕπ cos2 [ ]dzTvc
t
mL wf ∫ ′′=
∆∆ πρ2
Observations Model
ASSESSMENT
Instructor Comments•Prompted students to work in teams to solve problems•Deepened student engagement and motivation•Prompted greater class discussion and questions
Student CommentsStudent Comments•Helped reinforce theory•Enjoyed doing own experiments•“Show us more hands on experiments like these!”
ASSESSMENT
Students participating in laboratory components benefited more compared to those with no lab
RESOURCES
http://paoc.mit.edu/labguide/Flier on RAMADDAIllari, L., and coauthors, 2009: Weather in a Tank: Exploiting laboratory experiments in the teaching of Exploiting laboratory experiments in the teaching of meteorology, oceanography, and climate, Bull. Amer. Meteor. Soc., accepted.
ASSESSMENT
Students participating in laboratory components come from diverse backgrounds