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Title: Explaining the convector effect in canopy turbulence by means of large-eddy simulation

Semi-arid forests are found to sustain a massive sensible heat flux in spite of having a low surface to air temperature difference by lowering the aerodynamic resistance to heat transfer ( r H) – a property called the canopy convector effect (CCE). In this work large-eddy simulations are used to demonstrate that the CCE appears more generally in canopy turbulence. It is indeed a generic feature of canopy turbulence: r H of a canopy is found to reduce with increasing unstable stratification, which effectively increases the aerodynamic roughness for the same physical roughness of the canopy. This relation offers a sufficient condition to construct a general description of the CCE. In addition, we review existing parameterizations for r H from the evapotranspiration literature and test to what extent they are able to capture the CCE, thereby exploring the possibility of an improved parameterization.
Authors:
ORCiD logo [1] ;  [1] ; ORCiD logo [1]
  1. Karlsruhe Inst. of Technology (KIT), Garmisch-Partenkirchen (Germany). Inst. of Meteorology and Climate Research. Atmospheric Environmental Research (IMK-IFU)
Publication Date:
Report Number(s):
LA-UR-17-22651
Journal ID: ISSN 1607-7938
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Hydrology and Earth System Sciences (Online)
Additional Journal Information:
Journal Name: Hydrology and Earth System Sciences (Online); Journal Volume: 21; Journal Issue: 6; Journal ID: ISSN 1607-7938
Publisher:
European Geosciences Union (EGU)
Research Org:
Karlsruhe Inst. of Technology (KIT), Garmisch-Partenkirchen (Germany); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; German Research Foundation (DFG); Helmholtz Association (Germany)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; canopy turbulence; large eddy simulation; canopy convector effect; aerodynamic resistance
OSTI Identifier:
1369206

Banerjee, Tirtha, De Roo, Frederik, and Mauder, Matthias. Explaining the convector effect in canopy turbulence by means of large-eddy simulation. United States: N. p., Web. doi:10.5194/hess-21-2987-2017.
Banerjee, Tirtha, De Roo, Frederik, & Mauder, Matthias. Explaining the convector effect in canopy turbulence by means of large-eddy simulation. United States. doi:10.5194/hess-21-2987-2017.
Banerjee, Tirtha, De Roo, Frederik, and Mauder, Matthias. 2017. "Explaining the convector effect in canopy turbulence by means of large-eddy simulation". United States. doi:10.5194/hess-21-2987-2017. https://www.osti.gov/servlets/purl/1369206.
@article{osti_1369206,
title = {Explaining the convector effect in canopy turbulence by means of large-eddy simulation},
author = {Banerjee, Tirtha and De Roo, Frederik and Mauder, Matthias},
abstractNote = {Semi-arid forests are found to sustain a massive sensible heat flux in spite of having a low surface to air temperature difference by lowering the aerodynamic resistance to heat transfer (rH) – a property called the canopy convector effect (CCE). In this work large-eddy simulations are used to demonstrate that the CCE appears more generally in canopy turbulence. It is indeed a generic feature of canopy turbulence: rH of a canopy is found to reduce with increasing unstable stratification, which effectively increases the aerodynamic roughness for the same physical roughness of the canopy. This relation offers a sufficient condition to construct a general description of the CCE. In addition, we review existing parameterizations for rH from the evapotranspiration literature and test to what extent they are able to capture the CCE, thereby exploring the possibility of an improved parameterization.},
doi = {10.5194/hess-21-2987-2017},
journal = {Hydrology and Earth System Sciences (Online)},
number = 6,
volume = 21,
place = {United States},
year = {2017},
month = {6}
}