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Weather, Climate and Ecosystems Dennis Baldocchi University of California, Berkeley 6/3/2014 ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology 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) ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology Cold and Snowy in the East Warm and Dry in the West ESPM 111 Ecosystem Ecology Day to Day Variation in Mean Temperature Berkeley 30 25 Temperature 20 15 10 5 0 1980.0 1980.2 1980.4 1980.6 1980.8 Day-Year ESPM 111 Ecosystem Ecology ESPM 111 Ecosystem Ecology Chemistry and Physics of the Atmosphere ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology 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 P MA g ESPM 111 Ecosystem Ecology Atmospheric Temperature Profile ESPM 111 Ecosystem Ecology Planetary Boundary Layer ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology Comparison between Planck’s Law for Sun and Earth Planck's Law 1e+15 1e+14 Earth, T = 298 K Sun, T = 5800 K 1e+13 1e+12 Energy (T, ) 1e+11 1e+10 1e+9 1e+8 1e+7 1e+6 1e+5 1e+4 1e+3 1e-8 1e-7 1e-6 1e-5 Wavelength, microns ESPM 111 Ecosystem Ecology 1e-4 1e-3 1e-17 H2O CO2 1e-18 -1 -2 Absorption Cross-Section (cm /(molecule cm ) Many Atmospheric Trace Gases Absorb & Re-emit Infrared Radiation 1e-19 1e-20 1e-21 1 10 Wavelength (microns) HI-Tran Database ESPM 111 Ecosystem Ecology 100 www.GlobalwarmingArt.com ESPM 111 Ecosystem Ecology www.GlobalwarmingArt.com ESPM 111 Ecosystem Ecology Trenberth et al 2009 BAMS ESPM 111 Ecosystem Ecology Basic Earth/Sun Geometry ESPM 111 Ecosystem Ecology Lapse Rates, Temperature Decreases with Height • Dry Adiabatic Lapse Rate Change in Internal Energy Equals Change in Work Done on the Air Parcel – 9.8 C km-1 • Moist Adiabatic Lapse Rate – 6 C km-1 ESPM 111 Ecosystem Ecology Concepts of Thermal Stratification unstable thermal stratifiation Tparcel < Tair Tparcel > Tair T z Temperature ESPM 111 Ecosystem Ecology Height, m Height, m Height, m near neutral stability T z stable thermal stratification T z Adiabatic Lapse Rate, Lifted Condensation Level and Clouds http://www.sci.uidaho.edu/scripter/geog100/lect/05-atmos-water-wx ESPM 111 Ecosystem Ecology Orographic Precipitation Air Lifted by a Mountain, Cools, Can Condense, Form Clouds and Rain/Snow http://www.sci.uidaho.edu/scripter/geog100/lect/05-atmos-water-wx ESPM 111 Ecosystem Ecology Succession of Weather Fronts off the Pacific Coast of North America Role of High and Low Pressure Zones on Weather ESPM 111 Ecosystem Ecology Cold and Warm Fronts and Rain Two Ways to Lift Parcels of Air, Form Clouds and Rain http://www.worsleyschool.net/science/files/aboutweather/coldfront.gif ESPM 111 Ecosystem Ecology High and Low Pressure Systems in Northern Hemisphere Anti-Cyclonic Circulation: Air is Divergent Cyclonic Circulation Air is Convergent High LOW ESPM 111 Ecosystem Ecology Convergence: Air Rises, Temperature Decreases, Vapor Condenses, Clouds Form, Rain Possible LOW ESPM 111 Ecosystem Ecology Divergence: Air Sinks, Temperature Warms Cloud Formation is Suppressed High ESPM 111 Ecosystem Ecology Large Scale Patterns Dominating Weather in California Aleutian Low Steer Storm Tracks during Winter North Pacific High Block Storms during Summer http://www.pacificstormsclimatology.org/index.php?page=regional-overview 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 determines wind direction Circulation cells help explain global distribution of rainfall From Chapin ESPM 111 Ecosystem Ecology La Nina ESPM 111 Ecosystem Ecology El Nino http://weatherevents.co.uk/widespread-flooding-in-australia-and-the-affect-of-la-nina/ ESPM 111 Ecosystem Ecology Climate Distribution ESPM 111 Ecosystem Ecology IPCC dataset ESPM 111 Ecosystem Ecology IPCC dataset ESPM 111 Ecosystem Ecology ESPM 111 Ecosystem Ecology 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 ESPM 111 Ecosystem Ecology ESPM 111 Ecosystem Ecology Natural Solar Forcing of Climate Variability Over Geological Time Zachos et al Science 2002 Natural Forcing of the Climate System, last Million Years Source Rob Rohde, http://www.globalwarmingart.com/images/7/7e/Milankovitch_Variations.png ESPM 111 Ecosystem Ecology
