Soil Plants Atmosphere dynamics

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Marco Marani, from Padova University and Duke, presented a work on the soil-water-plants continuum. He emphasize the role of roots in modifying the soil water distribution, otherwise controlled by Darcy flows. However, he also studied and talked about the influence of the soil-plants-atmosphere continuum.

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Soil Plants Atmosphere dynamics

  1. 1. Duke University Some mechanisms of soil-plant-atmosphere interaction ! Marco Marani (Univ. di Padova & Duke Univ.) Gabriele Manoli (U. di Padova & Duke U.) Sara Bonetti (Duke U.) Valeria Volpe (U. di Padova) Gabriel Katul (Duke U.) John Albertson (Duke U.) Jean Cristophe Domec (Duke U.& U. de Bordeaux) Mario Putti (U. di Padova) Interdisciplinary  Workshop  on  Frontiers  in  Hydrology  and   Hydrogeoscience   8-­9  May  2014,  Venice  International  University,  Venice,  Italy
  2. 2. Soil-plant-atmosphere interactions are important Pe Pi P ET Atmospheric Input Atmospheric Output Incoming Runoff Outgoing Runoff Study Region Global water cycle Regional water recycling Terrestrial Carbon cycle Crop responses to…
  3. 3. Vegetated soil Bare soil Soil moisture dynamics in vegetated and bare soils Volpeetal.,2013
  4. 4. Transpiration and Photosynthesis, an often-neglected coupling
  5. 5. Transpiration and Photosynthesis An often-neglected coupling Importance of root distribution (li) in determining overall resistance to flow.
  6. 6. ( ) ( )[ ] xRRLLxLR AzzψgT ⋅+−+⋅−= ψψψ ),( ( ) ( )[ ] riiRRiLRi Azzgq ⋅+−+⋅−= ψψψψ ),( cwLsLw ALAIVPDgaf ⋅⋅⋅⋅⋅= εψψ )()( Soil-Plant-Atmosphere continuum model Leaf-Atmosphere Xylem-Leaf Root-Xylem ΨR ΨL CO2 gx gs gs T 0= ∂ ∂ − ∂ ∂ s w s c g f g f λ (Katul et al., 2010) ( )Lsg ψ ( )[ ] ( )Lrs w ws qzKK t S t SS ψψψϕ ψ ,++∇⋅∇= ∂ ∂ + ∂ ∂ Variably saturated flow (Cathy): H2O (Volpe et al., 2011) Volpe et al., 2013; Manoli et al., 2014 (Paniconi and Putti, 1994)
  7. 7. Root vs. Darcy flows integrated within the root zone Volpe et al., 2013
  8. 8. Manoli et al., 2014 Model and obs. in NC Coastal Forest
  9. 9. RWU RWU Root Hydraulic Redistribution Root Hydraulic Redistribution Darcy flow divergence Darcy flow divergence RootHydraulicRedistributionandspatialinteractions Manolietal.,2014
  10. 10. Lumped Transpiration-Soil Saturation Relations Pure drainage Infiltration & drainage Manoli et al., 2014
  11. 11. Clouds Transpiration z ABL LCL Free Atmosphere sunrise mid-morning SoilPlantAtmosphere mid-afternoon
  12. 12. Clouds z ρ [Ωm] 200 40 120 ABL LCL Free Atmosphere sunrise mid-morning SoilPlantAtmosphere mid-afternoon Transpiration
  13. 13. Convective Rainfall Initiation Bonetti et al., 2014
  14. 14. Convective Rainfall Initiation ),( RHTzz aLCLLCL = ABLT sABL z H dt dz ⋅ +⋅ = γ β)1( ( ) ( )( )STGfLETR c H wSn ap s −−− ⋅ = ρ 1 ( )VPDgg Lss ,ψ= ( ) ( ) 100 RH TeTeVPD asss ⋅−= ( ) dt dz TTH dt dT z ABL aFAs a ABL ⋅−+= ( ) dt dz ww LE dt dw z ABL FA a ABL ⋅−+= λρ z Conservation Eqs. (well mixed ABL ): ABL potential temperature, Ta Specific humidity, w ( )[ ] ( )Lrs w ws qzKK t S t SS ψψψϕ ψ ,++∇⋅∇= ∂ ∂ + ∂ ∂ Bonetti et al., 2014
  15. 15. Modeled ABL-LCL intersection and observed rainfall
  16. 16. Soil-Plant-ABL model Atmospheric feedback When atmospheric feedback Is turned off RAIN NO RAIN MoisturefromFreeAtmosphere
  17. 17. Conclusions Importance of water vertical redistribution in increasing water availability to plants. Relative role of root vs. Darcy water redistribution; overlapping root systems enhance water stress but do not alter averaged Transpiration vs. mean soil moisture relations; the role of vegetation controls and WT fluctuations on the predisposition of convective rainfall Coupled carbon and water uptake modeling contribute to understanding collective responses of carbon and water cycles. ρ [Ωm] 200 40 120 Challenges and Opportunities Getting the right results for the right reason requires space- time characterizations of active root biomass: ERT and SPA modeling to play an important role. Root biomass allocation strategies: SPA modeling and Space- time active root mapping to yield insight into biomass allocation strategies. Climate change responses of the SPA system: subgrid parameterization?

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