Weather, Climate and Ecosystems 111 Climate System.pdfrainfall) ESPM 111 Ecosystem Ecology. 3...
Transcript of Weather, Climate and Ecosystems 111 Climate System.pdfrainfall) ESPM 111 Ecosystem Ecology. 3...
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ESPM 111 Ecosystem Ecology
Weather, Climate and Ecosystems
Dennis BaldocchiUniversity of California, Berkeley
2/1/2013
ESPM 111 Ecosystem Ecology
Weather, Climate and Ecosystems: Outline
• Concepts– Atmospheric Meteors and Composition– ‘Greenhouse-Effect’ Principles– Seasons– Global and Regional Circulation
• Climate– Climate Forcing and Variability– Global Temperature, Precipitation and Radiation
Maps
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Weather and Climate Meteors
• Electromagnetic Radiation– Solar (shortwave) and Terrestrial (longwave)– f(season, clouds)
• Temperature– Air, soil, vegetation
• Wind Velocity and Direction• Moisture
– Gaseous: vapor pressure, Relative Humidity, dew point
– Liquid: Rain, dew, clouds– Solid: snow, sleet, frost, hail, rime, clouds
• Pressure
Many Ecological Processes are a Function of, or Correlate with, Climate and Weather
• Photosynthesis = f(sunlight, temperature, humidity, rainfall)
• Evaporation = f(sunlight, temperature, humidity, rainfall)
• Respiration = f(temperature, rainfall)
• Decomposition =f(temperature, rainfall)
• Ecosystem Structure and Function = f(sunlight, temperature, rainfall)
• Soil Formation and Nutrition= f(temperature, rainfall)
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Weather vs Climate
• Weather is the Recent Condition of the Atmosphere, yesterday, today, tomorrow– Weather is Chaotic, can Exhibit Extreme
Behavior
• Climate is the Average Condition of the Atmosphere over long-time durations, e.g. 30 years, Century, Millennium– Climate is relatively stable, e.g. summers are
hot, winters are coldESPM 111 Ecosystem Ecology
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Weather/Climate Concepts• Atmosphere is a Dynamic and Complex System
– Multiple Positive and Negative Feedbacks that operate across a Spectrum of Time and Space Scales
– Non-Linear Processes– Sensitivity to Initial Conditions– Experiences Strange Attractors, so is Phase Space is
Constrained– Thresholds and Tipping Points
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Chemistry and Physics of the Atmosphere
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Atmospheric Composition
• Nitrogen– 78.084%
• Oxygen– 20.946%
• Argon– 0.934%
• Carbon Dioxide– 0.0395%
• Water Vapor– 0.1 to 4%
• Trace Gases– Nitrous Oxide, CO, Methane, Ozone, VOCs
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Partial Pressure Law
• Total Pressure is the sum of the partial pressures of its components– P=pn2+po2+par+ph2o+pco2+…
• P at sea level, 101.3 kPa
• P equal mass of overhead atmosphere time acceleration due to gravity, per unit area
AP M g
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Atmospheric Temperature Profile
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Solar Constant
• 1366 J m-2 s-1 or W m-2
• Amount of Energy Available to Drive Work by the Climate System and Life
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Planck's Law
Wavelength, m
1e-8 1e-7 1e-6 1e-5 1e-4 1e-3
Ene
rgy
(T,
)
1e+3
1e+4
1e+5
1e+6
1e+7
1e+8
1e+9
1e+10
1e+11
1e+12
1e+13
1e+14
1e+15
Sun, T = 5800 KEarth, T = 298 K
Comparison between Planck’s Law for Sun and Earth
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Wavelength (microns)
1 10 100
Ab
sorp
tion
Cro
ss-S
ect
ion
(cm
-1/(
mol
ecu
le c
m-2
)
1e-21
1e-20
1e-19
1e-18
1e-17
H2O
CO2
HI-Tran Database
Many Atmospheric Trace Gases Absorb & Re-emit Infrared Radiation
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www.GlobalwarmingArt.com
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ESPM 111 Ecosystem Ecologywww.GlobalwarmingArt.com
ESPM 111 Ecosystem Ecology
Trenberth et al 2009 BAMS
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Basic Earth/Sun Geometry
Lutgens/Tarbuck, Atmosphere
Zachos et al Science 2002
Natural Solar Forcing of Climate Variability Over Geological Time
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Source Rob Rohde, http://www.globalwarmingart.com/images/7/7e/Milankovitch_Variations.png
Natural Forcing of the Climate System, last Million Years
Timing of Ice Ages
• MilankovitchTheory states Glaciers form when solar intensity is weak during summer of northern latitudes, as when Earth is less tilted with orbital plane (e.g. Obliquity with 41 ky cycles)
• Isotope show ice-ages grow and wane with 41 ky cycle for Early Pleistocene (1-3 Million yBP) and 100ky cycle in late Pleistocene (0-1 Million yBP)– Eccentricity of Earth’s orbit with 100 ky cycle has a weak forcing on
summer insolation
• The integral of solar radiation (time x intensity), not peak irradiance, controls 41 ky timing of ice age of the Early Pleistocene (1 to 3 million ybp)– This corresponds with Obliquity, which has 41 ky cycle instead of 100 ky
with Eccentricity because Summers are shorter when Earth is closer to Sun and Radiation is greatest
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Lapse Rates, Temperature Decreases with Height
• Dry Adiabatic Lapse Rate– 9.8 C km-1
• Moist Adiabatic Lapse Rate– 6 C km-1
Change in Internal Energy Equals Change in Work Done on the Air Parcel
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Adiabatic Lapse Rate, Lifted Condensation Level and Clouds
http://www.sci.uidaho.edu/scripter/geog100/lect/05-atmos-water-wx
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He
igh
t,m
z
T
unstablethermal
stratifiation
He
igh
t,m
stablethermal
stratification
z
THe
igh
t,m
near neutralstability
z
T
Tparcel > Tair
Tparcel < Tair
Concepts of Thermal Stratification
Temperature
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Orographic PrecipitationAir Lifted by a Mountain, Cools, Can
Condense, Form Clouds and Rain/Snow
http://www.sci.uidaho.edu/scripter/geog100/lect/05-atmos-water-wx
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Succession of Weather Fronts off the Pacific Coast of North AmericaRole of High and Low Pressure Zones on Weather
ESPM 111 Ecosystem Ecology
LOW
High
Cyclonic CirculationAir is Convergent
Anti-Cyclonic Circulation:Air is Divergent
High and Low Pressure Systems in Northern Hemisphere
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Convergence:Air Rises, Temperature Decreases,Vapor Condenses, Clouds Form,Rain Possible
LOW
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Divergence:Air Sinks, Temperature WarmsCloud Formation is Suppressed
High
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http://www.worsleyschool.net/science/files/aboutweather/coldfront.gif
Cold and Warm Fronts and RainTwo Ways to Lift Parcels of Air, Form Clouds and Rain
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Large Scale Patterns Dominating Weather in California
Aleutian Low Steer Storm Tracks during Winter
North Pacific High Block Storms duringSummer
http://www.pacificstormsclimatology.org/index.php?page=regional-overview
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Weltzin et al 2003 Bioscience
Rainfall Periodicity and Scale
ESPM 111 Ecosystem Ecology
Differential Solar heating causes Air to rises at equator and subsided at poles
This is superimposed upon the Earth’s rotation and the Coriolis Force which determineswind direction
Circulation cells help explain global distribution of rainfall
From Chapin
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La Nina
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El Nino
http://weatherevents.co.uk/widespread-flooding-in-australia-and-the-affect-of-la-nina/
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Climate Distribution
ESPM 111 Ecosystem EcologyIPCC dataset
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ESPM 111 Ecosystem EcologyIPCC dataset
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Summary
• Solar Energy Drives Weather and Climate• Trace Gases that absorb and re-radiate energy
warm the atmosphere and Earth’s surface above its radiative equilibrium value
• Differential heating of the Earth and its Rotation causes circulation of the air
• Different declination, relative to the Sun, causes the seasons.
Discussion PointsNext Ice Age?
• Would Occur within next 1500 Years if CO2 did not rise above 280 ppm?
• Will Future Generations Hate or Thank Us– With 7+ Billion People Living on Earth what
would happen if we did not stave off the Next Ice Age?
– Is our Fossil Fuel Emissions a form of GeoEngineering to Prevent the Next Ice age?
• Tzedakis et al. 2012 Nature GeoscienceESPM 111 Ecosystem Ecology