Part III: Some consequences of the Coriolis Effect

Transcription

1 Dynamic meteorology without tears Part III: Some consequences of the Coriolis Effect 21/05/ rd Moscow lecture May 2016

2 The Coriolis effect V 10 m/s 79 km A 10 m/s frictionless motion of an object only affected by the Coriolis force, will at latitude 60 N result in an approximate circular motion with a radius of about 79 km 21/05/2016 3rd Moscow lecture May

3 The Coriolis effect V 10 m/s 79 km 21/05/2016 3rd Moscow lecture May

4 1. Inertia circle motion in oceans 21/05/2016 3rd Moscow lecture May

5 2. Taylor columns (Inertia circles in a water tank) ink Non rotating 21/05/2016 3rd Moscow lecture May 2016 Rotating 5

6 Whenever a water parcel tries to move away it is brought back by the Coriolis force in an inertia circle Any motion away has a component perpendicular to the axis of rotation and is therefore subjected to the Coriolis effect 21/05/2016 3rd Moscow lecture May

7 When the water above the ping-pong ball tries to move away it is brought back by the Coriolis force in an inertia circle When the water below the ping-pong ball tries to move in behind it is brought back by the Coriolis force in an inertia circle 21/05/2016 3rd Moscow lecture May

8 3. Winds on our and other planets The equatorial jet circulation on Jupiter The hurricanes on the slow rotating Venus m/s m/s = 2-3% super-rationality Corso di previsioni meteorologichef 26 Trento, 1-5 Dec 2003 Anders Persson, SMHI Corso di previsioni meteorologichef 28 Trento, 1-5 Dec 2003 Anders Persson, SMHI Possible misunderstandings are that the winds on Jupiter are strong because it rotates rapidly, and the winds on Venus are weak because it rotates slowly but the opposite is true 21/05/2016 3rd Moscow lecture May

9 The rotation of the earth exerts a constraining effect on the motion over its surface Inertia circles for approx. 30 m/s 21/05/2016 3rd Moscow lecture May

10 Small inertia circles High rotation - strong Coriolis force The flow is only slightly super rotational... and closer to the equator 21/05/2016 3rd Moscow lecture May

11 P-G. William s computer simulations =1 The earth 50 Pole 30 Equat. 60 m/s =8 Pole 30 Equat. 21/05/2016 3rd Moscow lecture May

12 The relatively weak equatorial jet stream on Jupiter Its absolute strengths derives from the size of the planet m/s = 2-3% super-rationality 21/05/2016 3rd Moscow lecture May

13 Large inertia circles Slow rotation - weak Coriolis force The flow is highly super rotational... and away from the equator 21/05/2016 3rd Moscow lecture May

14 P-G. William s computer simulations =1 The earth 50 Pole 30 Equat. =1/16 80 m/s Pole 30 Equat. 21/05/2016 3rd Moscow lecture May

15 The hurricane winds on the slow rotating Venus m/s m/s 21/05/2016 3rd Moscow lecture May

16 4. The geostrophic wind How the French Academy in 1859 derived the geostrophic equation without being aware of it! The Seine s g 21/05/2016 3rd Moscow lecture May

17 The water in the Seine would be deflected to the right hand bank of the river perhaps flooding Paris?? The Seine Coriolis! s g 21/05/2016 3rd Moscow lecture May

18 z fv g z V s g f s s ρ 2Vρ sin =fvρ z gρ 21/05/2016 Lecture B Friday 22 April Anders Persson, Uppsala 18

19 5. Sloping weather fronts (stratified fluid) z s fv 2 g 2 fv1 1 g 1 f g V2 2 V1 1 2 tan -2Vρ 1 sin = -fvρ 1. ρ1 gρ 1 s ρ 2 2Vρ 2 sin=fvρ 2 z gρ 2 21/05/2016 Lecture B Friday 22 April Anders Persson, Uppsala 19

20 The slope of frontal surfaces (Margules equation) With rotation the Coriolis force tries to turn back the air... 21/05/2016 3rd Moscow lecture May

21 Margules s formula Separating wall J Max Margules Rotating box with liquid or gas The density differences try to equalize, the Coriolis effect tries to restore tan g f T T V w c V T c w 21/05/2016 3rd Moscow lecture May

22 6. El Niño and la Niña Asia USA Equator Australia S. Am. 21/05/2016 3rd Moscow lecture May

23 Asia USA Equator Australia The Trades put the warm ocean surface water in motion eastwards S. Am. 21/05/2016 3rd Moscow lecture May

24 Divergent ocean water at the equator Asia USA Australia The Trade winds put the ocean surface water in motion and is deflected away from the equator by the Coriolis effect S. Peru Am. 21/05/2016 Lecture A Friday 22 April 24 Anders Persson, Uppsala

25 The cold equator during La Niña Asia The divergence of the ocean surface leads to upwelling of cold water USA Australia S. Peru Am. 21/05/2016 Lecture A Friday 22 April 25 Anders Persson, Uppsala

26 Convergent ocean water at the equator Asia USA El Niño Australia The anti-trade wind puts the ocean surface water in motion and is deflected toward the equator by the Coriolis effect S. Am. 21/05/2016 Lecture A Friday 22 April 26 Anders Persson, Uppsala

27 The warm equator during El Niño Asia The convergence of the ocean surface leads to down welling of warm water USA El Niño Australia...and keeps the warm water in the El Niño close to the equator S. Am. 21/05/2016 Lecture A Friday 22 April 27 Anders Persson, Uppsala

28 21/05/2016 Lecture A Friday 22 April 28 Anders Persson, Uppsala

29 End 21/05/2016 3rd Moscow lecture May