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