SIO15-SS1 20: Topic 15: The Atmosphere and Climate SIO15-SS1 20: - - PowerPoint PPT Presentation

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

cl clima mate: average long-term condition; controlled by location regional to global weather weather: short-term condition; controlled by atmospheric anomalies local to regional cl clima mate: “I “I live ve in Sa San Diego beca cause se it ra rains s in Se Seattle” weather: r: “Sa “San Diego got so soake ked last st week” k”

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

how mu much ch so solar r ra radiation is s re rece ceive ved in any y are rea?

insolation per area: greater when Sun is

• verhead than near poles

Ma Marsh rshak: k: Ea Eart rth, Po Port rtra rait of a Pl Planet

zenith Se Seaso sons Sh Short rt vi video 11a

annually 2.4 times lower at poles than at equator

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

how mu much ch so solar r ra radiation is s re retained in any y are rea?

Albedo: fraction of insolation reflected back to space

• 80% fresh snow
• 30-90% clouds
• 25% grass
• 10% oceans

THE E DUAL AL FUNCTION OF H2O WATER ER VAPO APOR: most abundant greenhouse gas (warms) CLOUDS: S: reflect sunlight back into space (cools)

Ma Marsh rshak: Ea Eart rth, Po Port rtra rait of a Pl Planet

Se Seaso sons Sh Short rt vi video 11a

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

• 30% re

refle flect cted back ck to sp space ce

• 51% abso

sorb rbed at su surf rface ce

• 19% abso

sorb rbed by y atmo mosp sphere re Ea Eart rth’s s su surf rface ce emi mits s mo more re heat (I (IR) ) than it re rece ceive ves

Ahrens: Meteorology Today

se see Fig 11.4

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

Earth’s atmosphere acts like a greenhouse

greenhouse gases: H2O, CO2, CH4

• transparent to visible, UV light
• absorb infrared
• reflect IR back to Earth
• > trap heat

Earth with greenhouse: 16ºC/61ºF Earth without greenhouse: 34ºC/61ºF colder -> -18ºC/0ºF

Fig 1 Fig 11.8 1.8

H2O most abundant greenhouse gas

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

3) Earth’s tilted axis orbits Sun sun in zenith at different times (+/- 23.5º N/S) local insolation changes throughout the year

Ma Marsh rshak: Ea Eart rth, Po Port rtra rait of a Pl Planet

Fig 1 Fig 11.15 1.15

summer in San Diego but winter in Santiago, Chile

sh short rt Video 11a

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

• pposite seasons between

N and S hemispheres

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

• pposite seasons between

N and S hemispheres

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

Abbott: Natural Disasters Marshak: Earth, Portrait of a Planet

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

polar ice, subpolar Tundra, subtropical (temperate), dry land (desert), tropical plus: highland, continental

Marshak: Earth, Portrait of a Planet

Fig 1 Fig 11.7 1.7

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

• oceans store more heat than atmosphere
• oceans are climate moderators

(negative feedback) coastal areas have less extreme climate

Heat Capaci city: y: ability y to abso sorb rb heat without getting hot

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

• ocean processes longer-term than atmospheric processes
• > ocean currents slower than atmospheric winds
• currents blocked by continents
• Driving Mechanism: cold and salty water sinks

(thermohaline circulation)

source: Wikipedia

exact shape of heat conveyor not well known

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

Marshak: Earth, Portrait of a Planet

• warm western boundary currents (e.g. Gulf Stream)
• cold eastern boundary currents (e.g. California Current)

(think May Grey/June Gloom!)

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

atmosphere has less CO2 than humans produced in last 150 yrs

• ceans take up CO2
• it’s not (only) the rain forest!

leads to ocean acidification

but what we do know!

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

50% air below 5.6 km 90% air below 16 km 99.99997% below 100km

• air pressure: push due to weight of

atmosphere above

• greatest at sea level:

1 atmosphere, 14.7 PSI, 1035 mbar (g/cm2)

• pressure and density decrease

exponentially with altitude

simple

sh short rt Video 11b

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

• T-function

changes with altitude

• decreases from 18ºC to -55ºC in

troposphere

• increases in stratosphere
• decreases in mesosphere
• increases in thermosphere

complicated

sh short rt Video 11b

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

troposphere: lower 10km; weather layer, mixing stratosphere: next 35km; very dry, no vertical mixing, O3 layer mesosphere: less O3; meteorites burn up thermosphere: < 1% air; (ISS at ~350 km) Layers follow T-function

sh short rt Video 11b

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

it take kes s 600 ca cal to eva vapora rate 1g water eva vapora ration: water r va vapor r abso sorb rbs s heat co condensa sation: water r va vapor r re release ses s heat

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

SIO15-SS1 20: Topic 15: The Atmosphere and Climate

CA farmers did NOT have time to do this to protect citrus

• Fig. 11.13
• Fig. 2.12