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Title: Investigating the mechanisms responsible for the lack of surface energy balance closure in a central Amazonian tropical rainforest

This work investigates the diurnal and seasonal behavior of the energy balance residual (E) that results from the observed difference between available energy and the turbulent fluxes of sensible heat (H) and latent heat (LE) at the FLUXNET BR-Ma2 site located in the Brazilian central Amazon rainforest. The behavior of E is analyzed by extending the eddy covariance averaging length from 30 min to 4 h and by applying an Information Flow Dynamical Process Network to diagnose processes and conditions affecting E across different seasons. Results show that the seasonal turbulent flux dynamics and the Bowen ratio are primarily driven by net radiation (R n), with substantial sub-seasonal variability. The Bowen ratio increased from 0.25 in April to 0.4 at the end of September. Extension of the averaging length from 0.5 (94.6% closure) to 4 h and thus inclusion of longer timescale eddies and mesoscale processes closes the energy balance and lead to an increase in the Bowen ratio, thus highlighting the importance of additional H to E. Information flow analysis reveals that the components of the energy balance explain between 25 and 40% of the total Shannon entropy with higher values during the wet season than the dry season.more » Dry season information flow from the buoyancy flux to E are 30–50% larger than that from H, indicating the potential importance of buoyancy fluxes to closing E. While the low closure highlights additional sources not captured in the flux data and random measurement errors contributing to E, the findings of the information flow and averaging length analysis are consistent with the impact of mesoscale circulations, which tend to transport more H than LE, on the lack of closure.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [6] ;  [9] ;  [8]
  1. Montana State Univ., Bozeman, MT (United States). Dept. of Land Resources and Environmental Sciences; Pennsylvania State Univ., University Park, PA (United States). Dept of Meteorology and Atmospheric Science
  2. Northern Arizona Univ., Flagstaff, AZ (United States). School of Informatics, Computing, and Cyber Systems
  3. Pennsylvania State Univ., University Park, PA (United States). Dept of Meteorology and Atmospheric Science
  4. Embrapa Amazonia Oriental, Belem, PA (Brazil)
  5. Univ. of Kansas, Lawrence, KS (United States). Dept. of Geography and Atmospheric Science
  6. Univ. do Estado do Amazonas (UEA), Manaus, AM (Brazil)
  7. National Inst. of Amazonian Research (INPA), Manaus, AM (Brazil)
  8. Montana State Univ., Bozeman, MT (United States). Dept. of Land Resources and Environmental Science
  9. Brazilian Ministry of Science, Technology and Innovation, Sao Jose dos Campos, Sao Paulo (Brazil). National Inst. for Space Research (INPE)
Publication Date:
Grant/Contract Number:
SC0011075; 1552976; 1632810; 1417914
Type:
Accepted Manuscript
Journal Name:
Agricultural and Forest Meteorology
Additional Journal Information:
Journal Volume: 255; Journal ID: ISSN 0168-1923
Publisher:
Elsevier
Research Org:
Montana State Univ., Bozeman, MT (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF)
Contributing Orgs:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM), Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; eddy covariance; energy balance closure; evapotranspiration; information theory sensible heat flux; tropical rainforest
OSTI Identifier:
1368353