weather, climate and ecosystems · espm 111 ecosystem ecology weather, climate and ecosystems:...

ESPM 111 Ecosystem Ecology

Weather, Climate and Ecosystems

Dennis BaldocchiUniversity of California, Berkeley

6/3/2014


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


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)


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 cold



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– Coherent Features Emerge, like Hurricanes and Tornadoes


Warm and Dry in the West

Cold and Snowy in the East


Berkeley

Day-Year

1980.0 1980.2 1980.4 1980.6 1980.8

Tem

pera

ture

0

5

10

15

20

25

30

Day to Day Variation in Mean Temperature


Chemistry and Physics of the Atmosphere


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


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


Atmospheric Temperature Profile


Planetary Boundary Layer


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


Comparison between Planck’s Law for Sun and Earth

Planck's Law

Wavelength, microns

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

Earth, T = 298 KSun, T = 5800 K


Wavelength (microns)

1 10 100

Abso

rptio

n C

ross

-Sec

tion

(cm

-1/(m

olec

ule

cm-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


www.GlobalwarmingArt.com

ESPM 111 Ecosystem Ecologywww.GlobalwarmingArt.com


Trenberth et al 2009 BAMS


Basic Earth/Sun Geometry


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


Hei

ght,

m

zT

unstablethermal

stratifiation

Hei

ght,

m

stablethermal

stratification

zTH

eigh

t,m

near neutralstability

zT

Tparcel > TairTparcel < Tair

Concepts of Thermal Stratification

Temperature


Adiabatic Lapse Rate, Lifted Condensation Level and Clouds

http://www.sci.uidaho.edu/scripter/geog100/lect/05-atmos-water-wx


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


Succession of Weather Fronts off the Pacific Coast of North AmericaRole of High and Low Pressure Zones on Weather


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


LOW

High

Cyclonic CirculationAir is Convergent

Anti-Cyclonic Circulation:Air is Divergent

High and Low Pressure Systems in Northern Hemisphere


Convergence:Air Rises, Temperature Decreases,Vapor Condenses, Clouds Form,Rain Possible

LOW


Divergence:Air Sinks, Temperature WarmsCloud Formation is Suppressed

High


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


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


La Nina


El Nino

http://weatherevents.co.uk/widespread-flooding-in-australia-and-the-affect-of-la-nina/


Climate Distribution

ESPM 111 Ecosystem EcologyIPCC dataset


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.

• Rising air parcels, by fronts, topography or instability, can cool, condense, form clouds and rain

Zachos et al Science 2002

Natural Solar Forcing of Climate Variability Over Geological Time


Source Rob Rohde, http://www.globalwarmingart.com/images/7/7e/Milankovitch_Variations.png

Natural Forcing of the Climate System, last Million Years

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