Simulated Seasonal Spatio-temporal Patterns of Soil Moisture, Temperature, and Net Radiation in a Deciduous Forest<br />Je...
Outline<br />Motivation and Objective<br />Approach and Description of the SRSS<br />Simulation Results<br />Future Work<b...
Introduction<br />Both the temperature and moisture regimes in the forest are some of the most important components in for...
Dry Conditions<br />
Moist Conditions<br />Flooded Conditions<br />
Motivation<br />Both heat and fluid processes are well studied in trees, but little is known of the interactions of the pr...
Objectives<br />Develop a three-dimensional computational tool that simulates the radiative energy, conductive heat, and m...
Research Questions<br />How do you simulate the forest without explicitly simulating the forest?<br />During periods of hi...
Research Approach<br />If we treat the behavior of water in the soil and xylem similarly, it should be possible to model t...
SRSS Components<br />Radiative Heat Transfer<br />Simulates radiative energy in the domain<br />Simulates solar energy int...
Simulation Assumptions<br />Fluid in the system is constant viscosity and density<br />All fluid movement occurs in a poro...
SRSS Component Verification<br />Conduction  in unsaturated porous media<br />Radiative heat transfer<br />Sky radiative h...
SRSS Application to Historical Simulations<br />Derby and Gates (1965)<br />Herrington (1964)<br />
SRSS Application for a Tree within a Forest<br />Simulate a single mature tree<br />Located in a temperate deciduous fores...
SRSS Application<br />Single tree in a mature deciduous forest<br />Both winter and early summer simulation<br />
Computational Domain<br />12x15x8 m domain<br />2-m above soil, 6-m below the soil<br />Top stem exiting fluid flow driven...
Mesh Development<br />Requirements<br />Realistic trunk and root system<br />Allows anisotropic thermal and fluid properti...
LIDAR Scan of Root System<br />Raw Data<br />Centerline Selection<br />Solid Geometry<br />
Stem Cross-Sections<br />
Winter<br />
Early Summer<br />
Simulation Results<br />
Early Summer Example<br />
Surface Heat Flux<br />
Growth of Unsaturated Soil Region<br />
Simulation Analyses<br />Temperature profiles along cardinal radius lines<br />Flow vs. no flow<br />Open vs. close canopy...
N<br />W<br />E<br />S<br />0.6<br />Bark<br />Xylem1<br />5.5<br />Xylem2<br />Xylem3<br />9.4<br />Heartwood<br />0.6<br...
Winter trunk temperatures<br />North radius at 0.6m<br />South radius at 0.6m<br />
Winter thermal radiation<br />1.3m<br />0.6m<br />0.3m<br />
Flow effect on Temperature<br />flow<br />no flow<br />flow – no flow<br />Early summer<br />North radius at 0.6m<br />
Analyses Summary<br />Winter simulations agree with observations showing that the primary influence of temperature in the ...
Research Answers<br />The SRSS demonstrated the ability to simulate accurately the physics of thermal radiation without ex...
Future Work<br />Inclusion of dense understory vegetation<br />Long-term full season simulations<br />Drought simulations<...
Thank You<br />
Inclusion of understory vegetation<br />
Critical Time Steps<br />
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SIMULATED SEASONAL SPATIO-TEMPORAL PATTERNS OF SOIL MOISTURE, TEMPERATURE, AND NET RADIATION IN A DECIDUOUS FOREST.pptx

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SIMULATED SEASONAL SPATIO-TEMPORAL PATTERNS OF SOIL MOISTURE, TEMPERATURE, AND NET RADIATION IN A DECIDUOUS FOREST.pptx

  1. 1. Simulated Seasonal Spatio-temporal Patterns of Soil Moisture, Temperature, and Net Radiation in a Deciduous Forest<br />Jerry Ballard1, Stacy Howington1, Pasquale Cinella2, and Jim Smith3<br />1US Army ERDC<br />2Mississippi State University<br />3NASA / GSFC<br />27 July 2011<br />
  2. 2. Outline<br />Motivation and Objective<br />Approach and Description of the SRSS<br />Simulation Results<br />Future Work<br />
  3. 3. Introduction<br />Both the temperature and moisture regimes in the forest are some of the most important components in forest ecosystem dynamics<br />Affects: <br />Tree growth and development<br />Onset and cessation of cambial activity<br />Nesting success of avian species (tree cavities)<br />Uptake and metabolism of pollutants from the soil<br />Growth and treeline elevation limitation<br />Influences forest fire intensity and tree survivability<br />
  4. 4. Dry Conditions<br />
  5. 5. Moist Conditions<br />Flooded Conditions<br />
  6. 6. Motivation<br />Both heat and fluid processes are well studied in trees, but little is known of the interactions of the processes temporally or spatially.<br />Some work exists for coupled 1- or 2-D heat and fluid flow in trees, but rarely in three dimensions.<br />
  7. 7. Objectives<br />Develop a three-dimensional computational tool that simulates the radiative energy, conductive heat, and mass transfer interaction in a soil-root-stem system (SRSS).<br />Verify process components of the SRSS and apply to a seasonally varying deciduous forest in a temperate environment.<br />
  8. 8. Research Questions<br />How do you simulate the forest without explicitly simulating the forest?<br />During periods of high mass transfer, how much heat is transported by the fluid flow compared to conduction and radiative effects?<br />What is the effect of the root system on the spatial and temporal distributions of temperature and moisture content in the soil?<br />
  9. 9. Research Approach<br />If we treat the behavior of water in the soil and xylem similarly, it should be possible to model the xylem as a porous medium<br />Develop radiative transfer model that estimates infrared contribution from the surrounding environment using form factors derived from hemispherical images<br />Construct a macro-scale model of a tree-root-soil system and simulate different seasonal time periods.<br />
  10. 10. SRSS Components<br />Radiative Heat Transfer<br />Simulates radiative energy in the domain<br />Simulates solar energy into the domain<br />Monte Carlo multiprocessor C code<br />Heat and Mass Transfer in Porous Media<br />Simulates time varying thermal and fluid material properties<br />Mass and momentum based on Richards’ equation<br />Multiprocessor C code (ADH)<br />
  11. 11. Simulation Assumptions<br />Fluid in the system is constant viscosity and density<br />All fluid movement occurs in a porous medium<br />Fluid velocities constitute a creeping flow (Re < 10)<br />Air is always at atmospheric pressure<br />No radiative heat transfer occurs in the pore space in the solids<br />Within a volume of porous media, the temperatures of water and air are the same<br />All surfaces are diffuse and are treated as grey black bodies<br />The air gap between surfaces neither attenuates or emits thermal radiation<br />
  12. 12. SRSS Component Verification<br />Conduction in unsaturated porous media<br />Radiative heat transfer<br />Sky radiative heat transfer<br />Shortwave solar radiation<br />Convective heat transfer in porous media<br />
  13. 13. SRSS Application to Historical Simulations<br />Derby and Gates (1965)<br />Herrington (1964)<br />
  14. 14. SRSS Application for a Tree within a Forest<br />Simulate a single mature tree<br />Located in a temperate deciduous forest<br />Seasonally and diurnally varying<br />Time-lapse thermal imagery movie<br />
  15. 15. SRSS Application<br />Single tree in a mature deciduous forest<br />Both winter and early summer simulation<br />
  16. 16. Computational Domain<br />12x15x8 m domain<br />2-m above soil, 6-m below the soil<br />Top stem exiting fluid flow driven by time-varying flow<br />Bottom of domain<br />Saturated soil condition<br />Constant temperature<br />Surface of domain<br />Modified by diurnal varying solar radiation<br />
  17. 17. Mesh Development<br />Requirements<br />Realistic trunk and root system<br />Allows anisotropic thermal and fluid properties<br />Hydraulically connected<br />
  18. 18.
  19. 19.
  20. 20.
  21. 21.
  22. 22. LIDAR Scan of Root System<br />Raw Data<br />Centerline Selection<br />Solid Geometry<br />
  23. 23.
  24. 24.
  25. 25.
  26. 26. Stem Cross-Sections<br />
  27. 27.
  28. 28.
  29. 29.
  30. 30. Winter<br />
  31. 31. Early Summer<br />
  32. 32. Simulation Results<br />
  33. 33. Early Summer Example<br />
  34. 34. Surface Heat Flux<br />
  35. 35. Growth of Unsaturated Soil Region<br />
  36. 36.
  37. 37. Simulation Analyses<br />Temperature profiles along cardinal radius lines<br />Flow vs. no flow<br />Open vs. close canopy<br />
  38. 38. N<br />W<br />E<br />S<br />0.6<br />Bark<br />Xylem1<br />5.5<br />Xylem2<br />Xylem3<br />9.4<br />Heartwood<br />0.6<br />9.6<br />4.8<br />12.5<br />3.4<br />0.8<br />12.7<br />8.3<br />4.8<br />0.6<br />
  39. 39. Winter trunk temperatures<br />North radius at 0.6m<br />South radius at 0.6m<br />
  40. 40. Winter thermal radiation<br />1.3m<br />0.6m<br />0.3m<br />
  41. 41. Flow effect on Temperature<br />flow<br />no flow<br />flow – no flow<br />Early summer<br />North radius at 0.6m<br />
  42. 42. Analyses Summary<br />Winter simulations agree with observations showing that the primary influence of temperature in the trunk is solar driven.<br />Flow in summer simulations show up to a 2 deg C change in internal temperature due to fluid flow<br />Both winter and summer simulations show internal temperatures affected by surrounding forest radiation and soil conduction<br />
  43. 43. Research Answers<br />The SRSS demonstrated the ability to simulate accurately the physics of thermal radiation without explicitly modeling the entire forest.<br />During periods of moderate fluid flow, simulations showed up to a 2 deg C change in temperature accounting for conduction and radiative effects.<br />Fluid flow from the soil into the roots creates unsaturated soil regions that vary diurnally and changes the thermal properties of the soil.<br />
  44. 44. Future Work<br />Inclusion of dense understory vegetation<br />Long-term full season simulations<br />Drought simulations<br />Additional validation studies<br />Macro vs. micro scale root fluid uptake analysis needed<br />
  45. 45. Thank You<br />
  46. 46. Inclusion of understory vegetation<br />
  47. 47.
  48. 48. Critical Time Steps<br />
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