Lesson7a Jupiter

Jupiter properties

On Earth the rotation is

so rapid that the Hadley cell turns

east before it reaches the North

pole.

High Pressure region in the Northern Hemisphere.

Air circulation is clockwise around a high pressure region. (Anti-cyclone)

North

Equator

H

High Pressure region in the Southern Hemisphere.

Rotation is counter-clockwise for high pressure.

South

Equator

H

High Pressure regions

• High pressure regions on Earth are fair weather regions.

• In order to form clouds, air currents must raise up to altitudes where water vapor turns into water droplets and forms clouds.

• High pressure stops the ability for these type of currents to form.

• The result is sunny weather.

Regions of low pressure in the Northern Hemisphere.

• When a region develops where the air pressure is lower than in surrounding regions the air flow is into the low pressure region.

Equator

L

North

What will happen to inflowing wind in a Low Pressure area in the Northern Hemisphere?

L

North

Equator

In Northern Hemisphere, low pressure systems rotate counter-clockwise. This is called a

cyclone.

L

Equator

North

Low Pressure Systems

• In the Southern Hemisphere, lows rotate clockwise.

• Low pressure means that air is flowing into the region and can develop air currents that move upwards, where the air is cooler.

• When this happens, water vapor condenses to from droplets and clouds form.

• Low pressure means clouds and rain.

Hurricane (cyclone)

Summary• Weather patterns are in general governed by

two processes.#1. Energy has to heat the air. On Earth this

energy comes from the Sun heating the equator. This sets up wind currents toward the poles.

#2. The rotation of the planet causes a Coriolis Effect which changes the direction of the wind currents. This sets up changes in the motion of the wind currents and also produces cyclones (low-pressure) and anti-cyclones.

Mars cyclone

Jupiter

PropertiesEquatorial Radius: 71,492 km (11.2 times Earth)Polar Radius: 66,854 km (10.5 times Earth)Mass: 318 times the EarthVolume: 1321 times the EarthMean Density: 1.33 gm/cm3 (Earth is 5.5 gm/cm3)Rotational Period: 9.925 Earth Hours

Rotational speed at equator = (2πR)/9.925 hoursRotational speed at equator = 45,300 km/hrThat’s 29 times faster than the Earth.

Low mean density.• Composition: 89.8% Hydrogen 10.2% Helium 0.3% Methane (CH4)

0.026% Ammonia (NH3)

Composition of the Sun: 91.2% Hydrogen 8.7% Helium 0.8% Oxygen 0.4% Carbon 0.1% Nitrogen

Structure of Jupiter

Rocky core?

Metallic Hydrogen(ionized)

Liquid Hydrogen

Gaseous Hydrogen

Jupiter heat source

• Jupiter is at a distance of 5.2 A.U. from the Sun.

• The Sun’s intensity drops like 1/d2

• How much energy/meter2 does Jupiter get from the Sun compared to the Earth?

.

1 2 3 4 5 6

0% 0% 0%0%0%0%

1. Around 5 times more2. Around 5 times less3. Around 25 times more4. Around 25 times less5. Around 100 times more6. Around 100 times less

• Call IE the energy the Earth gets per unit area from the Sun and IJ for Jupiter.

IE is proportional to 1/dE2 IE α 1/dE

2 and

IJ α 1/dJ2

IE/IJ = (1/dE2)/(1/dJ

2) = dJ2/dE

2 = (5.2 AU)2/(1 AU)2

IE/IJ = 27 or IE = 27*IJ

Earth gets 27 times the energy from the Sun as Jupiter does (per meter squared).

Jupiter in

Infrared

• So, given the location of the bright infrared regions compared to the visual image,

What can you say about the darker regions

in the visual image of Jupiter?

• Why is the absorbed heat (red line) curved while the green line is flat?

.

1 2

0%0%

1. Jupiter’s rapid rotation shares all the emitted heat equally at every latitude.

2. Jupiter’s internal heat is emitted evenly at all latitudes

• The Sun does heat up Jupiter, especially near the equator, but even there it is far less than what Jupiter emits from its internal heat.

• This means Jupiter is different than the Earth in a fundamental way.

• Earth weather patterns get energy from the Sun. Jupiter weather patterns are driven predominantly by its internal heat.

Atmospheric Composition

• The upper cloud layers of Jupiter are mostly composed of ammonia (NH3), methane (CH4), water (H20) and Hydrogen-sulfide (H2S).

• At certain layers these compounds either from droplets of liquid, or freeze to form ice crystals.

Atmospheric temperature

profile

• http://upload.wikimedia.org/wikipedia/commons/8/8b/PIA02863_-_Jupiter_surface_motion_animation_10fps.ogv

Wind velocity profile

• Pay special attention to the Great Red Spot. • What do you notice about the it, compared

to the overlaid plot?

Turbulence

Low pressure near Equator because air is moving upward. This

forms clouds and storms.

Hadley cell and polar cell collide and make turbulence.

Today from Unisys Weather

Turbulence