tropics: insolation high year round, high sun angle and ...ozone depletion what is ozone? ... carbon...

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GEO 101, February 6, 2014

Finish insolation variation

Global environmental issues associated with insolation

TROPICS: insolation high year round, high sun angle and ~ constant duration

MID-LATITUDES: insolation highest at summer solstice, higher sun angle and longer day, lowest at winter solstice due to low angle and short day

Poles: insolation highest at summer solstice due to 24 hour duration low angle sun, none at winter solstice

Total annual insolation decreases as latitude increases

Seasonality (difference between winter and summer) increases as latitude increases

Global average annual energy balance

Surplus

DeficitTropics

Mid-High latitudes

San FranciscoSt. LouisWashington DC

Insolation on the June SolsticeComparison between top of atmosphere and Earth surface

Top of atmosphere

N. P

ole

Eq

uat

or

Duration factor23.5°N

90°N

80°N

70°N

60°N

50°N

40°N

30°N

20°N

10°N

00°N

10°S

20°S

30°S

40°S

50°S

60°S

70°S

80°S

90°SJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

16

48

40

44

3236

2824

12

20

0

48

90° sun elevation

Meg

ajo

ule

s/m

2 /d

ay

At

top

of

the

atm

osp

her

e

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0 0 0 0 0 0244039 4420 1

Chart monthly insolation at the North Pole

44

40 36 32 28

2024

16

12

8

4

812

16

2024

28

32 36

2

Chart of monthly insolation at the North Pole(dark bars = N.P., light are Equator for reference)


5

45

35

25

15

50

40

30

20

10

Chart monthly insolation at the South Pole


44 25 06 0 0 0 0 0 17 37 49

12

16

20

24

28

32

36

40

44

12

16

20

24

28

32

36

40

44

90° S

Example only, do not use your sheet for this demo. problem.Class assignment: if your last name begins with

A-B, do 80°N and 10°S

C-D, do 70°N and 20°S

E-H, do 60°N and 30°S

I-L, do 50°N and 40°S

M, do 40°N and 50°S

N-Q, do 30°N and 60°S

R-T, do 20°N and 70°S

U-Z, do 10°N and 80°S

Graphs will be due on Tuesday

Incoming shortwave radiation

Outgoing longwave radiation

Ultraviolet Thermal infrared

Shortwave infrared

Visible light

From sun to earth

From earth to space

50%41%9%

Two global environmental issues related to interaction of atmospheric gases, insolation, and outgoing Earth radiation

Ozone Greenhouse gases

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For greenhouse warming and ozone depletion, be able to explain:

•basics of how it works

•problem

•causes of the problem

•consequences

•possible solutions

O2

O3

Earth’s atmosphere is unique: not at chemical equilibrium (entropy). Highly reactive atmosphere reveals life.

N2

Ozone depletion What is ozone?

Naturally occurring form of oxygen with 3 oxygen atoms in molecule instead of usual two.

O2 is what we need to breathe

O3 is a highly reactive gas

(like breathing chlorox fumes)

~400 mya

~2.4 bya

~3.7 bya

~4.6 bya

Land plants

Photosynthetic bacteria

Single cell organisms

Earth formed

Oxygen revolution

Sulfur dioxide

Nitrogencompounds

Life (as we know it) evolved under ozone layer protection

Carbon dioxide

Methane

Where is ozone?

90% of O3 found in stratosphere

good ozone: blocks UV radiation

10% of O3 near Earth’s surface

bad ozone: toxic to life

4

Normal equilibrium

O2 + UV O + O

O2 + O O3

O3 + UV O2 + O

Most O3 produced in tropical stratosphere and transported poleward

Manmade chemicals interfere with equilibrium

Man-made chemicals that destroy ozone

•CFCs (chlorofluorocarbons), HCFCs: refrigerants, foam blowing agents, aerosol propellants

•Halons: old fire extinguishers

•Carbon tetrachloride: solvent

•Methyl chloroform: solvent, aerosols, cleaners, (labeled as 1,1,1-trichloroethane)

•Methyl bromide: pesticide (soil fumigant) used heavily on tomatoes and strawberries (Banned in 2005)

All are long lasting

Global environmental problem

Identified in 1980s

Stratospheric O3 concentrations decreasing

Most noticeable in Antarctica

TOMS = Total Ozone Mapping SpectrometerOMI = Ozone Monitoring Instrument

0.0

5.0

10.0

15.0

20.0

25.0

30.0

1975 1980 1985 1990 1995 2000 2005 2010 2015

Ozone Hole Area in million km2

How do CFCs destroy ozone?

Ultraviolet radiation strikes a CFC molecule

C

Cl ClCl

F

...and causes a chlorine atom to break away

Cl

Chlorine atom collides with an ozone molecule

OO

O


...creates molecule of regular oxygen and chlorine monoxide

5

ClO

O


Free oxygen atom collides with chlorine monoxide

...yields a molecule of regular oxygen and a free chlorine atom

chlorine is freed to react again

In winter, chlorine attaches to ice clouds in stratosphere above pole. This keeps ozone-depleting chlorine “locked up”

When ice melts in spring (September in Antarctica), chlorine is freed and attacks O3 “hole”

http://ozonewatch.gsfc.nasa.gov/

What’s so bad about it?

1% ozone loss ~

5-7% increase in skin cancer

Cataracts

Immune system suppression

Inhibits plant growth

Globally, what’s being done about it?

Montreal Protocol, 1987

World production

World production

Montreal Protocol relatively successful because

1. Problem obviously man-made

2. Scientists agreed on cause and solution

3. No major country’s economy based on CFCs

You personally can:

•FIX leaky auto air conditioners

(#1 CFC, HCFC, HFC source in US)

6

Greenhouse warmingWhat are greenhouse gases?

Range is from blue (low) to red (high)

What are anthopogenic greenhouse gases?Approximate percent responsibility for problem

Halocarbons

How does it work?

GG

http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.htmlhttp://cdiac.ornl.gov/trends/co2/jubany.html

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Are current CO2 levels that unusual?

Ice core records

http://www.ncdc.noaa.gov/cag/time-series/global

Global Land and Ocean Temperature Anomalies1880 - present

http://www.ncdc.noaa.gov/cag/time-series/globalCauses of CO2 concentration increase

Deforestation

Burning of fossil fuels

Causes of CO2 concentration increase What are fossil fuels?

Gas

Liquid

Solid

8

Top Ten CO2 emitters in 2008 (million metric tons of carbon/ year)

http://www.ucsusa.org/global_warming/science_and_impacts/science/each-countrys-share-of-co2.html

2008 per capita fossil-fuel CO2 emission rates. expressed in metric tons of carbon.

Consequences may be

• Higher sea levels due to ocean expansion and ice melting (inundation of island nations)

• More intense storms

• Disruption of agriculture

• Extinctions

• Spread of tropical diseases

What’s being done globally?

Kyoto Protocol: 1997 : agreement to reduce greenhouse gas emissions by % of 1990 levels.

Entered into force on February 16, 2005

United States never ratified protocol

Kyoto Protocol not as successful because

1. Problem itself highly debated

2. Developed countries’ economies based on fossil fuels

3. Developing countries’ forests are source of income

4. China’s energy needs met by coal

Much more expensive to implement Kyoto Protocol

What can you do personally ?

Conserve energy

Drive fuel efficient vehicle

Insulate home

Recycle (saves energy)

on-campus paper and aluminum

Plant trees

tropics: insolation high year round, high sun angle and ...ozone depletion what is ozone? ... carbon...

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