2006 自然科学の英語 -ens-l2 the atmosphere - global warming l2 english in natural science...
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2006 自然科学の英語 -ENS-L2
The Atmosphere - global warming L2
English in Natural Science
自然科学の英語
2006 自然科学の英語 -ENS-L2
2006 自然科学の英語 -ENS-L2
Vertical structure • Density decreases with altitude
– gravitational force
• Layers of different composition
– Homosphere (90 km)– Heterosphere
Mesosphere
Stratosphere
Troposphere
90 km
48 km
12 km
Heterosphere
Homosphere
Ozone layer
Mass
< 1%
14%
85%
2006 自然科学の英語 -ENS-L2
Ozone layer• Filter (15-40 km) against UV solar radiation
90% ozone [O3] 2-8 ppm
• Destruction by CFC: CFCl3 + hv CFCl3 + Cl
O3 + Cl O2 + ClO Effects
1. Increased UV radiation DNA damage
(mutations, cancer)
2. Less absorption of radiation
Air cooling
2006 自然科学の英語 -ENS-L2
• Current composition – N2 (78.08%)– O2 (20.95%)– Ar (0.93%)– CO2 (0.035%)– Other (0.005%)
• Ne, He, CH4, Kr, NO2-, H, Xe, O3
• Temperature decreases with altitude– average 1 oC for 100 m
surface ~15 oC 1,500 m water condensates– Clouds form between 1500-3000 m
N278%
O221%
otherCO2Ar1%Troposphere
2006 自然科学の英語 -ENS-L2
Evolution of atmosphere
95% N2
3.5% CO2
<1% O2
78% N2
21% O2
<1% CO2
2006 自然科学の英語 -ENS-L2
Atmosphere is dynamic• Solar powered• Convection
– Hot air UP– Cold air DOWN
• Circulation routes– west east– tropics poles
• Jet streams• Effects:
– Mixing of gasses– Temperature buffer
2006 自然科学の英語 -ENS-L2
Coriolis effect
• Rotation of the Earth– Air moves inward in
circles cyclons– Inertial circles
C
Centrifugal force
Tropical cyclon台風 typhoon
hurricane
2006 自然科学の英語 -ENS-L2
Hydrological cycleEnergy Sun
Water on Earth• Oceans (97%)
– Salty water
• Atmosphere – Evaporation (H2O vapour)
– Condensation (cloud)
– Precipitation (rain)
• Land– Snow icecaps water
– Runoff rivers• Dissolves materials• Erosion of land
– Evapotranspiration (plants)
Evapotranspiration
2006 自然科学の英語 -ENS-L2
The Blue Planet
2006 自然科学の英語 -ENS-L2
Hydrosphere - water distribution
Location Volume (km3) Percentage
Oceans 1,322,000,000 97.2
Icecaps + glaciers 29,200,000 2.15
Water on land 8,630,000 0.635
World total 1,360,000,000 100.0
Ground water 8,400,000 0.62
Freshwater lakes 125,000 0.009
Saline lakes/seas 104,000 0.008
Soil moisture 67,000 0.005
Atmosphere 13,000 0.001
Rivers 1,250 0.0001
2006 自然科学の英語 -ENS-L2
Interaction atmosphere - hydrosphere
• Solar radiation– Water evaporation (oceans) condensation
(clouds)– Hot air UP and cold air DOWN
• Earth’s rotation– Air + clouds move in inertial circles (cyclons)
• Earth’s topography (e.g. mountains)– Distort movement of cyclons– Cause precipitation (rain)– Region different weather pattern
CLIMATE
2006 自然科学の英語 -ENS-L2
Climate patternsKoeppen System
1st level: latitude zone• Tropical• Subtropical• Temperate• Polar• Mountain/highland
2nd level: precipitation• Regular throughout year• Dry winter• Dry summer
3rd level: temperature• Hot• Mild• Cool• Cold
2006 自然科学の英語 -ENS-L2
• Af: Tropical Rainforest
• Aw: Tropical Wet & Dry (Savanna)• BSh: Tropical Steppe• BWh: Tropical Desert• BSk & BWk: Midlatitude Steppe &
Desert
• Cs: Mediterranean (dry summer subtropical)
• Cfa: Humid Subtropical
• CFb: Marine West Coast
• Df & Dw: Humid Continental & Subarctic
• ET: Tundra
• Highland
2006 自然科学の英語 -ENS-L2
Climate change: Causes• Weather changes - short term cycles
– Sun spots fluctuations (11 yr period)– Sea-temperature currents (El Niño oscillations)
• Climate changes - long-term oscillations– Solar radiation (insolation)
• Precession of equinoxes (23,000 yr period)• Tilt (1o) of Earth’s rotational axis (41,000 yr period)• Eccentricity cycle (100,000 and 400,000 yr period) Milankovitch cycles
– Carbon dioxide and methane in atmosphere• Biomass amount and distribution
2006 自然科学の英語 -ENS-L2
Climate indicators
• 18O ice-sheet thickness
sea level
• 13C biomass (productivity)
• CO2 atmospheric temperature
carbonate deposition/dissolution
• CH4 wetland expansion/reduction
monsoonal precipitation
2006 自然科学の英語 -ENS-L2
Weather cycles
SouthernOscillation Index(El Niño)• cold dryness• warm rainfall
Humdbolt Current
Temperature cycles11 x 2 yr period
2006 自然科学の英語 -ENS-L2
Orbit eccentricity
Axial tilt
Astronomic variations insolation
Precession
Polaris<-->Vega
2006 自然科学の英語 -ENS-L2
Holocene (10,000 yr)
• Insolation– perihelion from July to January– 8% more insolation summer and less in winter NH
• Effects– Global ice-volume decreased (18O from 15,000 to
6,000 yr) – Sea-surface temperature up (8 oC Atlantic winter)– Sea level up (100 m)
• CO2 increased
– 200 ppm (15,000 yr) 250 ppm (6,000 yr)
2006 自然科学の英語 -ENS-L2
2006 自然科学の英語 -ENS-L2
Pleistocene (175,000 yr)
• Insolation– superimposition 23, 41 and 100 year cycles
• Effects– Ice-sheet (18O)– Sea-level
– CO2
– methane– Monsoon (SE Asia)
2006 自然科学の英語 -ENS-L2
2006 自然科学の英語 -ENS-L2
Quaternary (3 million yr)
• Directly related to insolation cycles
• Patterns of variation– Several ice-age periods– Cooling trend in last 700,000 yr – Changes in biomass (productivity)– Irreversible variations due to continental drift
• Mountain uplift regulate the magnitude of monsoonal oscillations
2006 自然科学の英語 -ENS-L2 (Webb and Bartlein, 1992)
2006 自然科学の英語 -ENS-L2
Greenhouse gasses• Transparent to incoming solar radiation• Absorb outgoing infrared radiation ( > 0.78 m) emitted
by Earth (surface + atmosphere)
CFC
Radiative forcing W/m2 relativeCO2 1.56 1CH4 0.5 58NO2 0.1 206CFC 0.3 3970 5750
CO2
+36%
CH4
+150%
NO2
+20%
2006 自然科学の英語 -ENS-L2
Carbon dioxide (CO2) and temperature
AntarcticaVostok lake (160,000 yr)
What causes CO2 cycles?
(Barnola et al., 1987)
2006 自然科学の英語 -ENS-L2
Keeling curve
Current CO2 in atmosphere
• Atmospheric CO2
– Initially (3.5 bya) 100 x– Reduction…
• Biomass• Carbonate deposition
– Now 300 Gt (x109 tons)• Upward trend
• Sources– 98% natural
• Biological• Volcanic eruptions
– 2% human activities
Before 1800 190-290 ppm 1800 280 ppm 2004 380 ppm
Total increase +36%Current rate 1.8 ppm/yr
2006 自然科学の英語 -ENS-L2
Human impact on the carbon cycle
Sources of CO2 6-8 Gt/year (1995)– Emissions (83%)
• Fossil fuels (CO2, CH4) 6.5 Gt• Fertilizers (NO2) 0.140 Gt
– Deforestation(17%) 0.4 m Km2/year 36,000 Km2 Amazon
2006 自然科学の英語 -ENS-L2
Carbon balance44% 36% 20%
2006 自然科学の英語 -ENS-L2
Effects: global warming
• Average air temperature increased
I) 0.7 oC in 30 yr
ii) 2003 heat wave
in Europe
94 mt harvest lost
(5% world grain)
2006 自然科学の英語 -ENS-L2
Effects in theocean… …
start to be felt.
• Sea levels in Gulf of Mexico
• Wild weather– Katrina, Rita– Japan 2004
(11 typhoons)
2006 自然科学の英語 -ENS-L2
Global climatic impact of CO2
• Global warming [CO2] UP Temperature UP
Temperature
– Air: more H2O vapour rainfall increase
pressure wild weather (typhoon)– Water: melting icecaps increase sea levels
[CO2]
– Air: photosynthesis UP more plant biomass
– Water:dissolved CO3-2 coral and marine plankton
• Ice-age [CO2] DOWN Temperature DOWN
– Air: less H2O vapour rainfall decrease
dryness dust UP less radiation (cooling)– Water:icecaps increase decrease sea levels
2006 自然科学の英語 -ENS-L2
Alternating warm/cold cycles
Warmperiods
[CO3Ca•Mg]
[CO2]
[CO3-2]
Ice
Temp
Vegetation
dissolve
[HCO3-]
Iceage
Vegetation
[CO3Ca•Mg]
[CO3-2]
Ice
[CO2]
Temp
precipitate
[HCO3-]
2006 自然科学の英語 -ENS-L2
References
• Schneider, S. H. 1989. The greenhouse effect: Science and policy. Science 243: 771-81.
• Webb III, T. and Bartlein, P.J. 1992. Global changes during the last 3 million years: Climatic controls and biotic responses. Annu. Rev. Ecol. Syst. 23: 141-173
• Wuebbles, D.J. and Jain, A.K. 2001. Concerns about climate change and the role of fossil fuel use. Fuel Proces. Technol. 71: 99-119
• Feely R.A. et al.2004. Impact of anthropogenic CO2 on the CaCO3 system in the oceans. Science 305: 362-366