modeling climate change in the laboratoryparrise.elte.hu/tpi-15/slides/vincze_miklos.pdf · a...

Modeling Climate Change in the Laboratory

Miklós Vincze

MTA-ELTE Theoretical Physics Research Group

ELTE Institute of Physics, von Kármán Laboratory for Enviromental Flows (HU),

BTU Cottbus-Senftenberg, Department of Aerodynamics and Fluid Mechanics (DE)

Intl. Conf. On Teaching Physics Innovatively – Budapest, HungaryAugust, 2015

First of all: What kind of laboratory?

A Laboratory for environmental flows (aka geophysical fluid dynamics), called Kármán Laboratory of Eötvös University

(hidden abbreviation: K.ár.mán. – can also stand for ‚Environmental Flow maniacs(?)’ in Hungarian)

Founded in 1998 by Imre M. Jánosi, Tamás Tél, Gábor K. Szabó, and Viktor Horváth

The principle of hydrodynamical similarity enables modeling large-scale(atmosphere, ocean) flow structures

Demonstration, teaching (incl. High school groups, Researchers’ Night, etc.), research

Website (www.karman.elte.hu) almost up-to-date…

Video (courtesy index.hu)

http://www.karman.elte.hu/



(hidden abbreviation: K.ár.mán. – can also stand for ‚EnvironmentalFlow maniacs(?)’ in Hungarian)


The principle of hydrodynamical similarity enables modeling large-scale (atmosphere, ocean) flow structures





A Laboratory for environmental flows (aka geophysical fluid dynamics), calledKármán Laboratory of Eötvös University






Video (courtesy index.hu) LINK: http://index.hu/video/2010/09/26/kutatok_ejszakaja_2010/ [from 02:00 to 04:00]


http://index.hu/video/2010/09/26/kutatok_ejszakaja_2010/

Hot topics







Video (courtesy: index.hu)


Why to use such a lab for research purposes nowadays? -#1: Lab experiments as ‚analog computers’

“It always bothers me that, according to the laws as we understand them today, it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space, and no matter how tiny a region of time.”

- R. P. Feynman

(In: The Character of Physical Law, 1967)

Why to use such a lab for research purposes nowadays? -#2: Test-bed for „Nimitz class” complex flow models

• A somewhat provocative statement:

The operational numerical methods and models for weather forasting and climate prediction can be validated only in the lab! (if at all)

So, what can be done?

•How to separate parametrization(discretization, etc.) errors from those that originate from our incomplete understanding of the system

•Let’s build/find a physical system which behaves like the atmosphere, but still much simpler, and all the governing equations are correctly understood!

A minimal model of mid-latitude weather

- A large variety of the typical atmospheric phenomena of the mid-latitudes are primarily driven by two factors only.

- Rotation + meridionaltemperature difference ≈ weather

- Let’s use a differentially heated rotating circular tank for method validation!

• A differentially heated cylindrical tank, mounted on a turntable. “Rotating annulus”

Geometrical parameters(Cottbus):

a = 45 mm

b = 120 mm

d = 135 mm


• A differentially heated cylindrical tank, mounted on a turntable. “Rotating annulus”

Geometrical parameters(Budapest):

a = 45 mm

b = 150 mm

d = 40 mm


Basics: baroclinic instability


“Sideways convection” – no

threshold in ΔT

(i.e. No ‘critical Rayleigh number’)

Any temperature difference can

initiate the flow


Rotation!

Baroclinic instability

Rotation!

Zonal flow

(thermal wind)

Geostrophic theory:

Tilted density

surfaces

Baroclinic instability

Rotation!

Zonal flow

(thermal wind)

Geostrophic theory:

Tilted density

surfaces

Baroclinic instability!

Baroclinic waves

- control parameters:

• rotation rate, radial temperature difference

- Different planetary atmospheres can be modelled

• Venus: slow rotation, zonal flow

• Earth: fast rotation Coriolis effect cyclones (“weather”)

Baroclinic waves, planetary analogies

- control parameters:

• rotation rate, radial temperature difference

- Different planetary atmospheres can be modelled

• Venus: slow rotation, zonal flow

• Earth: fast rotation Coriolis effect cyclones (“weather”)

The regime diagram (after Fultz)

Preliminary results

Comments, conclusions:

In the model decreasing equator-to-pole temperaturedifference seems to yield smaller fluctuations (in terms of magnitude)

Temporal behaviour needs to be investigated! (Expectation: smaller temperature difference makes the model weatherless predictable – smaller velocities, smaller cyclones, more freedom for the structures to interact)

Significant differences between the three runs! In manycases the trends are not even evident in the temperatureanomaly records! – A much-much larger ensemble is needed. (Work in progress.)

Climate is what you expect, weather is what you get.

Thank you for your attention!

modeling climate change in the laboratoryparrise.elte.hu/tpi-15/slides/vincze_miklos.pdf · a...

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