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Title: Improved representations of coupled soil–canopy processes in the CABLE land surface model (Subversion revision 3432)

CABLE is a global land surface model, which has been used extensively in offline and coupled simulations. While CABLE performs well in comparison with other land surface models, results are impacted by decoupling of transpiration and photosynthesis fluxes under drying soil conditions, often leading to implausibly high water use efficiencies. Here, we present a solution to this problem, ensuring that modelled transpiration is always consistent with modelled photosynthesis, while introducing a parsimonious single-parameter drought response function which is coupled to root water uptake. We further improve CABLE's simulation of coupled soil–canopy processes by introducing an alternative hydrology model with a physically accurate representation of coupled energy and water fluxes at the soil–air interface, including a more realistic formulation of transfer under atmospherically stable conditions within the canopy and in the presence of leaf litter. The effects of these model developments are assessed using data from 18 stations from the global eddy covariance FLUXNET database, selected to span a large climatic range. Here, marked improvements are demonstrated, with root mean squared errors for monthly latent heat fluxes and water use efficiencies being reduced by 40 %. Results highlight the important roles of deep soil moisture in mediating drought response and littermore » in dampening soil evaporation.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1]
  1. CSIRO Oceans and Atmosphere, Canberra, ACT (Australia)
  2. UFZ - Helmholtz Centre for Environmental Research, Leipzig (Germany)
Publication Date:
Grant/Contract Number:
FG02-04ER63917; FG02-04ER63911
Type:
Accepted Manuscript
Journal Name:
Geoscientific Model Development (Online)
Additional Journal Information:
Journal Name: Geoscientific Model Development (Online); Journal Volume: 9; Journal Issue: 9; Journal ID: ISSN 1991-9603
Publisher:
European Geosciences Union
Research Org:
Oregon State Univ., Corvallis, OR (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES
OSTI Identifier:
1361535