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Title: Daytime turbulent exchange between the Amazon forest and the atmosphere

Abstract

Detailed observations of turbulence just above and below the crown of the Amazon rain forest during the wet season are presented. The forest canopy is shown to remove high-frequency turbulent fluctuations while passing lower frequencies. Filter characteristics of turbulent transfer into the Amazon rain forest canopy are quantified. In spite of the ubiquitous presence of clouds and frequent rain during this season, the average horizontal wind speed spectrum and the relationship between the horizontal wind speed and its standard deviation are well described by dry convective boundary layer similarity hypotheses originally found to apply in flat terrain. Diurnal changes in the sign of the vertical velocity skewness observed above and inside the canopy are shown to be plausibly explained by considering the skewness budget. Simple empirical formulas that relate observed turbulent heat fluxes to horizontal wind speed and variance are presented. Changes in the amount of turbulent coupling between the forest and the boundary layer associated with deep convective clouds are presented in three case studies. Even small raining clouds are capable of evacuating the canopy of substances normally trapped by persistent static stability near the forest floor. Recovery from these events can take more than an hour, even duringmore » midday.« less

Authors:
;  [1];  [2];  [3]; ;  [4]
  1. State Univ. of New York, Albany (USA)
  2. Centro Nacional de Pesquisa da Seringueira e Dende-Embrapa, Manaus (Brazil)
  3. Universidade de Sao Paulo (Brazil)
  4. Instituto de Pesquisas Espaciais, Sao Paulo (Brazil)
Publication Date:
OSTI Identifier:
5937900
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research; (USA)
Additional Journal Information:
Journal Volume: 95:D10; Journal ID: ISSN 0148-0227
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CANOPIES; AIR-BIOSPHERE INTERACTIONS; WIND; TURBULENT FLOW; AMAZON RIVER; ATMOSPHERIC PRECIPITATIONS; BOUNDARY LAYERS; BRAZIL; CLOUDS; DAILY VARIATIONS; EARTH ATMOSPHERE; FLOW MODELS; FLUCTUATIONS; FORESTS; HEAT FLUX; MASS TRANSFER; MONITORING; RAIN; SEASONAL VARIATIONS; TURBULENCE; VELOCITY; DEVELOPING COUNTRIES; FLUID FLOW; LATIN AMERICA; LAYERS; MATHEMATICAL MODELS; RIVERS; SOUTH AMERICA; STREAMS; SURFACE WATERS; VARIATIONS; 540110*; 540210 - Environment, Terrestrial- Basic Studies- (1990-)

Citation Formats

Fitzjarrald, D R, Moore, K E, Cabral, M R, Scolar, J, Manzi, A O, and de Abreau Sa, L D. Daytime turbulent exchange between the Amazon forest and the atmosphere. United States: N. p., 1990. Web. doi:10.1029/JD095iD10p16825.
Fitzjarrald, D R, Moore, K E, Cabral, M R, Scolar, J, Manzi, A O, & de Abreau Sa, L D. Daytime turbulent exchange between the Amazon forest and the atmosphere. United States. https://doi.org/10.1029/JD095iD10p16825
Fitzjarrald, D R, Moore, K E, Cabral, M R, Scolar, J, Manzi, A O, and de Abreau Sa, L D. 1990. "Daytime turbulent exchange between the Amazon forest and the atmosphere". United States. https://doi.org/10.1029/JD095iD10p16825.
@article{osti_5937900,
title = {Daytime turbulent exchange between the Amazon forest and the atmosphere},
author = {Fitzjarrald, D R and Moore, K E and Cabral, M R and Scolar, J and Manzi, A O and de Abreau Sa, L D},
abstractNote = {Detailed observations of turbulence just above and below the crown of the Amazon rain forest during the wet season are presented. The forest canopy is shown to remove high-frequency turbulent fluctuations while passing lower frequencies. Filter characteristics of turbulent transfer into the Amazon rain forest canopy are quantified. In spite of the ubiquitous presence of clouds and frequent rain during this season, the average horizontal wind speed spectrum and the relationship between the horizontal wind speed and its standard deviation are well described by dry convective boundary layer similarity hypotheses originally found to apply in flat terrain. Diurnal changes in the sign of the vertical velocity skewness observed above and inside the canopy are shown to be plausibly explained by considering the skewness budget. Simple empirical formulas that relate observed turbulent heat fluxes to horizontal wind speed and variance are presented. Changes in the amount of turbulent coupling between the forest and the boundary layer associated with deep convective clouds are presented in three case studies. Even small raining clouds are capable of evacuating the canopy of substances normally trapped by persistent static stability near the forest floor. Recovery from these events can take more than an hour, even during midday.},
doi = {10.1029/JD095iD10p16825},
url = {https://www.osti.gov/biblio/5937900}, journal = {Journal of Geophysical Research; (USA)},
issn = {0148-0227},
number = ,
volume = 95:D10,
place = {United States},
year = {Thu Sep 20 00:00:00 EDT 1990},
month = {Thu Sep 20 00:00:00 EDT 1990}
}