1. Integrating Fluxes of Carbon Dioxide and Water Vapor From Leaf to Canopy Scales Dennis Baldocchi Ecosystem Science Division/ESPM UC Berkeley

2. Outline Overview Leaf-Canopy Scaling and Integration Concepts Show Tests of Such Models over Multiple Time Scales Use the CANVEG Model to Ask Ecophysiological and Micrometeorological Questions Relating to Trace Gas Fluxes

3. Classes of Model Complexity The breadth and linkage of functional components that describe the biophysics of trace gas exchange. How driving variables are defined and used as inputs to non-linear model algorithms. The geometric abstraction of the canopy.

4. ESPM 111 Ecosystem Ecology System Complexity: Interconnection of Key Ecosystem Processes

5. Processes and Linkages: Roles of Time and Space Scales

6. ESPM 111 Ecosystem Ecology 3-d Representation of Canopy Qi Chen and D. Baldocchi

7. ESPM 111 Ecosystem Ecology Geometrical Abstraction of the Canopy One-Dimensional –Big-Leaf –Dual Source, Sun-Shade –2-Layer Vegetation and soil –Multi-Layered Two-Dimensional –Dual source sunlit and shaded Vegetated vs Bare Soil Three-Dimensional –Individual Plants and Trees After Hanson et al Ecol Appl 2004

8. Big-Leaf Model

9. 2-Layer/Dual Source Models

10. Dual Source Model: Discrete Form Whole Canopy

11. ESPM 111 Ecosystem Ecology Role of Proper Model Abstraction

12. Sunlit Leaf Area and Sun Angle

13. Multi-Layer Models

14. CANOAK Schematic

15. ESPM 111 Ecosystem Ecology Basics of Ecosystem Models

16. Quantifying Sources and Sinks Biology: a(z), C i, r s Physics: r b, C(z)

17. Weight Source/Sink by Fraction of Sunlit and Shaded Leaves and Their Environment

18. Random Spatial Distribution: Poisson Prob Distr. Prob of Beam Penetration Prob of Sunlit Leaf

19. Sources of Spatial Heterogeneity Vertical Variations in: –Leaf area index –Leaf inclination angles –Leaf Clumping –Leaf N + photosynthetic capacity –Stomatal conductance –Light, Temperature, Wind, Humidity, CO 2

20. Vertical Profiles in Leaf Area

21. Vertical Variation in Sunlight

22. Carboxylation Velocity Profiles

23. Profiles of Ci/Ca

24. Turbulence Closure Schemes Lagrangian Eulerian –Zero Order, c(z)=constant –First Order, F=K dc/dz –Second Order and ++ (dc/dt, dw’c’/dt)

25. ESPM 228 Adv Topics Micromet & Biomet Higher Order Closure Equations and Unknowns

26. Lagrangian Near- and Far-Field Theory ESPM 228 Adv Topics Micromet & Biomet

27. Dispersion Matrix ESPM 228 AdvTopics Micromet & Biomet

28. Turbulent Mixing

29. Vertical Gradients in CO 2

30. Vertical Gradients in q and T

31. 13 C Profiles

32. Physiology Photosynthesis Stomatal Conductance Transpiration Micrometeorology Leaf/Soil Energy Balance Radiative Transfer Lagrangian Turbulent Transfer CANOAK MODEL

33. Examples: Non-Linear Biophysical Processes Leaf Temperature Transpiration Photosynthesis Respiration

34. Why Non-linearity is Important?

35. ESPM 129 Biometeorology35 Leaf Energy Balance R: is shortwave solar energy, W m -2 L: is Longwave, terrestrial energy, W m -2  E: Latent Heat Flux Density, W m -2 H: Sensible Heat Flux Density, W m -2

36. ESPM 129 Biometeorology36 Leaf Energy Balance, Wet, Transpiring Leaf Net Radiation is balanced by the sum of Sensible and Latent Heat exchange

37. ESPM 129 Biometeorology37 Derivation 1: Leaf Energy Balance 2: Resistance Equations for H and E 3: Linearize T 4 and e s (T)

38. ESPM 129 Biometeorology38 Linearize with 1 st order Taylor’s Expansion Series

39. ESPM 129 Biometeorology39 Linearize the Saturation Vapor Pressure function

40. ESPM 228, Advanced Topics in Micromet and Biomet W c, the rate of carboxylation when ribulose bisphosphate (RuBP) is saturated W j, the carboxylation rate when RuBP regeneration is limited by electron transport. W p carboxylation rate with triose phosphate utilization

41. ESPM 228, Advanced Topics in Micromet and Biomet If W c is minimal, then: If W j is minimal, then If W p is minimal, then

42. ESPM 228, Advanced Topics in Micromet and Biomet Analytical Equation for Leaf Photosynthesis Baldocchi 1994 Tree Physiology

43. ESPM 228, Advanced Topics in Micromet and Biomet Seasonality in V cmax Wilson et al. 2001 Tree Physiol

44. Results and Discussion

45. Model Test: Hourly to Annual Time Scale

46. Model Test: Hourly Data

47. Time Scales of Interannual Variability

48. Spectra of Photosynthesis and Respiration

49. Model Test: Daily Integration

50. Interannual Variability

51. ESPM 111 Ecosystem Ecology Hansen et al, 2004 Ecol Monograph Model Validation: Who is Right and Wrong, and Why? How Good is Good Enough?

52. Decadal Power Spectrum of CO 2 and Water Vapor Fluxes

53. NEE and Growing Season Length

54. GPP

55. Component C Fluxes

56. Light Use Efficiency and Net Primary Productivity NPP=  f Q p

57. LUE and Leaf Area

58. LUE and Ps Capacity

59. Emergent Processes: Impact of Leaf Clumping on Canopy Light Response Curves

60. Role of Leaf Clumping on Annual C and H 2 O Fluxes

61. Interaction between Clumping and Leaf Area

62. How Sky Conditions Affect NEE?

65. Knohl and Baldocchi, JGR Biogeosci 2008

66. Knohl and Baldocchi, 2008 JGR Biogeosci

68. Potential Impact of Aerosols/Clouds on NEE

69. Oxygen and NEE: Paleoclimates

70. Do We Need to Consider Canopy Microclimate [C] Feedbacks on Fluxes?

71. Leaf Temperature and Isoprene Emission?

72. Leaf size, CO 2 and Temperature: why oak leaves are small in CA and large in TN

73. Physiological Capacity and Leaf Temperature: Why Low Capacity Leaves Can’t Be Sunlit::or don’t leave the potted Laurel Tree in the Sun

74. Below Canopy Fluxes

75. Below Canopy Fluxes and Canopy Structure and Function

76. Impact of Thermal Stratification

77. Impact of Litter

78. Conclusions Biophysical Models that Couple Aspects of Micrometeorology, Ecophysiology and Biogeochemistry Produce Accurate and Constrained Fluxes of C and Energy, across Multiple Time Scales Models can be used to Interpret Field Data –LUE is affected by LAI, Clumping, direct/diffuse radiation, Ps capacity –NEE is affected by length of growing season –Interactions between leaf size, Ps capacity and position help leaves avoid lethal temperatures –Below canopy fluxes are affected by T stratification and litter