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Turbulent transport observed just above the Amazon forestObservations of turbulent heat, moisture, and momentum transport made at two levels, approximately 5 and 10 m above the Amazon rain forest canopy, are presented. Data acquired at 10 Hz included variances and some mixed third moments of vertical velocity, temperature, and humidity. Two features of the data appear to question the displacement height hypothesis: (1) the characteristic dissipation length scale in the near-canopy layer varied between 20 m in stable conditions to approximately 150 m during afternoon convective conditions, generally larger scales than would be expected, and (2) no appreciable differences in dissipation scales was seen at two observed levels. Heat budgets on selected days show that frequent periods with negative heat flux concurrent with continuing positive moisture flux occur in early afternoon, and this is believed to indicate the patchy nature of canopy-atmosphere coupling. Vertical velocity skewness was observed to be negative on three successive days and exhibited a sharp positive gradient. Time series of some of the terms in the turbulence budgets of vertical velocity variance and kinematic heat flux are presented.
Document ID
19880040040
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Fitzjarrald, David R.
(State Univ. of New York Albany, NY, United States)
Stormwind, Brian L.
(New York, State University Albany, United States)
Fisch, Gilberto
(Instituto Nacional de Pesquisas da Amazonia Manaus, Brazil)
Cabral, Osvaldo M. R.
(Empresa Brasileira de Pesquisa Agropecuaria Manaus, Brazil)
Date Acquired
August 13, 2013
Publication Date
February 20, 1988
Publication Information
Publication: Journal of Geophysical Research
Volume: 93
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
88A27267
Funding Number(s)
CONTRACT_GRANT: NAG1-583
Distribution Limits
Public
Copyright
Other

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