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  Folha Amazônica


CD-30 (Fitzjarrald / Mor„es / Acevedo / Cohen / M. Silva Dias / Manzi)

LBA Dataset ID:



1. Fitzjarrald, David Roy
2. Czikowsky, Matthew John
3. Da Silva, Rodrigo
4. Moura, Carlos Alberto Ribeiro de
5. Parker, Geoffrey
      6. Sa, Marta
7. Sakai, Ricardo
8. Silva, Julio Tota da
9. Zimermann, Hans Rogerio

Point(s) of Contact:

Silva, Julio Tota da (

Dataset Abstract:

It is now recognized that subcanopy transport of respired CO2 is missed by budgets that rely only on single point eddy covariance measurements, with the error being most important under nocturnal calm conditions. We tested the hypothesis that horizontal mean transport, not previously measured in tropical forests, may account for the missing CO2 in such conditions. A subcanopy network of wind and CO2 sensors was installed in the Tapajos National Forest in the state of Para. Two observational campaigns in 2003 and 2004 were conducted to describe subcanopy flows, clarify their relationship to winds above the forest, and estimate how they may transport CO2 horizontally.

Beginning Date:


Ending Date:


Metadata Last Updated on:


Data Status:

In Preparation for Archive

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Data Center URL:

Distribution Contact(s):

ORNL DAAC User Services (

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Citation Information - Other Details:

Tota, J., D. R. Fitzjarrald, R. M. Staebler, R. K. Sakai, O. M. M. Moraes, O. C. Acevedo, S. C. Wofsy, and A. Manzi. 2012. LBA-ECO CD-30 Subcanopy CO2 flow in mature Amazon forests. Data set. Available on-line [] from LBA Data and Information System, National Institute for Space Research (INPE/CPTEC), Cachoeira Paulista, Sao Paulo, Brazil

Keywords - Theme:

Parameter Topic Term Source Sensor

Uncontrolled Theme Keyword(s):  Amazon, subcanopy carbon flow

Keywords - Place (with associated coordinates):

(click to view profile)
(click to view profile)
North South East West
Para Western (Santarem) km 67 Primary Forest Tower Site -2.85700 -2.85700 -54.95900 -54.95900

Related Publication(s):

Tota, J., D. R. Fitzjarrald, R. M. Staebler, R. K. Sakai, O. M. M. Moraes, O. C. Acevedo, S. C. Wofsy, and A. Manzi. 2008. Amazon rain forest subcanopy flow and the carbon budget: Santarem LBA-ECO site, J. Geophys. Res., 113, G00B02, doi:10.1029/2007JG000597.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data are presented in (how many?) ASCII files. Observations include CO2, temperature, H2O and wind field measurements at 1 Hz

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

A field calibration was performed by co-locating sensors and gas inlets at the same point of measurement. The comparisons indicate scatter in CO2 concentration

because samples were sequential, not synchronous. The mean standard error was less than 0.05 ppm. The wind comparisons were made using a 3D sonic as the standard for the 2D sonic anemometers, resulting in a mean standard error of about 0.005 meters per second. Ambient subcanopy wind speed was on the

order of a few cm per second and can be reliably measured in the subcanopy space by the system.

We examined to what extent the subcanopy sensor geometry of CO2 allows the system to function as a network, whether the network can be used to capture the

relevant gradients and transport processes in very low wind conditions [Staebler and Fitzjarrald, 2004]. We assessed our choice of network size by examining observed spatial and temporal autocorrelations. The spatial autocorrelation of horizontal wind speed drops rapidly to 0.2 in 60 m, but

fluctuations in CO2 exhibit a larger integral scale 100�200 m while the temporal integral is approximately 100�300 s. This is consistent with results obtained by Staebler and Fitzjarrald [2004] in a very different forest, except that the characteristic horizontal CO2 scale is larger than that at Harvard Forest, consistent with the thicker canopy at the Tapajos National Forest. We

do not understand why the spatial correlations do not decrease with increasing distance, as was observed in Staebler and Fitzjarrald [2004]. This could be a consequence of the temporal scale variations being larger than are the spatial ones.

Process Description:

Data Acquisition Materials and Methods:

Study site

The study site is part of the Large Scale Biosphere-Atmosphere experiment in Amazonia (LBA-ECO), which aims to achieve better understanding of the regional carbon balance. It is located in the Tapajos National Forest reserve (FLONA

Tapajos), near km 67 of the Santarem-Cuiaba highway (BR-163). The average temperature, humidity, and rainfall are 25.8 degrees C, 85%, and about 1800 mm per year, respectively [Parotta et al., 1995]. This area contains predominantly

nutrient-poor clay oxisols with some sandy utisols [Silver et al., 2000], each of which has low organic content and cation exchange capacity. Vegetation consists of occasional 55 m height emergent trees with a closed canopy at 40 m and below [Parker and Fitzjarrald, 2004]. There is overall an uneven age distribution, but the forest can be considered to be primary or old growth [Clark,1996; Goulden et al., 2004]. Local topographic features include a steep nearby river escarpment sloping to the Tapajos River to the west, but with a weak eastward-facing slope into the basin of the Curua-Una watershed. Except near the escarpment, drainage flows would be expected to move opposing the easterly prevailing wind field. Several studies have demonstrated strong seasonal variations in solar radiation, net radiation, air temperature,

and vapor pressure deficit, all of which increase substantially with the seasonal decline in precipitation, while surface litter and soil moistures also decline [da Rocha et al., 2004].

Associated field measurements:

The field measurements at the old growth forest site at km67 in the LBA study area included several meteorological and EC measurements from 2001 though 2006, focusing on the dynamics of primary forest ecosystems. Several LBA groups have made observations of meteorological quantities, such as EC fluxes of H2O, CO2, temperature, and wind fields. The CD10 tower systems include EC and meteorological wind, CO2, temperature and water vapor profiles collected between 2001 and 2006. The instrumentation descriptions and quality control procedures for the basic data sets obtained at the main km67 tower site are given by Saleska et al. [2003]. A weather station was deployed in Jamaraqua at the base of the Tapajos escarpment to help in identifying topographical effects. A high resolution STRM map was made, based on a 90 m grid, interpolated to 30 m, to describe the gentle topography around the tower site.

Subcanopy field measurements:

Subcanopy network observations are available for two campaigns in 2003 (Phase 1, DOY 198-238) and 2004/2005 (Phase 2, DOY 250-366 and 01-32). The subcanopy

data complement observations that were made around the central 65-m tower. The observation and acquisition approach was developed at ASRC [Staebler and Fitzjarrald,2005] and includes a PC operating in Linux, an outboard Cyclades multiple serial port (CYCLOM-16YeP/DB25)collecting and merging serial data streams from all instruments in real time, with the data archived into 12-h ASCII files. Observations include CO2, temperature, H2O and wind field measurements at 1 Hz. The system included a LI-7000 Infrared Gas Analyzer (LI-COR inc., Lincoln, Nebraska, USA), a multiposition valve (Vici Valco

Instrument Co., Inc.) controlled by a CR23x Micrologger (Campbell Scientific, Inc., Logan, Utah, USA), which also monitored flow rates. The instrument network array consisted of 6 subcanopy sonic anemometers: a Gill HS (Gill Instruments Ltd., Lymington, UK) 3-component sonic anemometer at 5 m elevation in the center of the grid and 5 SPAS/2Y (Applied Technologies Inc., CO, USA)

2-component anemometers (1 sonic at center and 4 sonic along the periphery), with a resolution of 0.01 meters per second. The horizontal gradients of CO2/H2O were measured in the array at 2 m above ground, by sampling sequentially from 4 horizontal points surrounding the main tower location at

distances of 70-80 m, and from points at 6 levels on the small Draino tower, performing a 3-min cycle. Air was pumped continuously through 0.9 mm Dekoron tube (Synflex 1300, Saint-Gobain Performance Plastics, Wayne, NJ, USA) tubes from meshed inlets to a manifold in a centralized box. A baseline airflow of 4 LPM from the inlets to a central manifold was maintained in all lines at all times to ensure relatively ��fresh�� air was being sampled. The air was pumped for 20 s from each inlet, across filters to limit moisture effects. The delay time for sampling was 5 s, and the first 10 s of data were discarded. At the manifold, one line at a time was then sampled using an infrared gas analyzer (LI-7000, Licor, Inc.). The 6-level CO2 profile on the 5 m tower was determined in a similar, sequential manner, using a LI-7000 gas analyzer sampling pumped air from all 10 points (6 vertical, 4 horizontal) in the measurement array. Flow rates at the inlets were checked regularly to ensure proper flow and to detect potential leaks.


Clark, D. B. 1996. Abolishing virginity, J. Trop. Ecol., 12, 735� 739.

da Rocha, H. R., M. L. Goulden, S. D. Miller, M. C. Menton, L. D. V. O.

Pinto, H. C. de Freitas, and A. M. E. S. Figueira. 2004. Seasonality of

water and heat fluxes over a tropical forest in eastern Amazonia, Ecol,

Appl., 14(4, suppl. S), S22�S32.

Goulden, M. L., S. D. Miller, H. R. da Rocha, M. C. Menton, H. C. de

Freitas, A. M. E. S. Figueira, and C. A. D. de Sousa. 2004. Diel and

seasonal patterns of tropical forest CO2 exchange, Ecol. Appl., 14(4,

suppl. S), S42�S54.

Parker, G., and D. R. Fitzjarrald. 2004. Canopy structure and radiation

environment metrics indicate forest developmental stage, disturbance,

and certain ecosystem functions, paper presented at III LBA Scientific

Conference, Braz. Minist. of Sci. and Technol., Brasilia, Brazil, July.

Parotta, J. A., J. K. Franci, and R. R. de Almeida. 1995. Trees of the

Tapajos: A photographic field guide, Gen. Tech. Rep. IITF-1, 371 pp.,

U.S. Dep. of Agric., Rio Piedras, Puerto Rico.

Saleska, S. R., et al. 2003. Carbon in Amazon forests: Unexpected seasonal

fluxes and disturbance-induced losses, Science, 302(5650), 1554�1557.

Silver, W. L., et al. 2000. Effects of soil texture on belowground carbon

and nutrient storage in a lowland Amazonian forest ecosystem, Ecosystems 3, 193� 209.

Staebler, R. M., and D. R. Fitzjarrald. 2004. Observing subcanopy CO2

advection, Agric. For. Meteorol., 122(3� 4), 139� 156.

Staebler, R. M., and D. R. Fitzjarrald. 2005. Measuring canopy structure

and kinematics of subcanopy flows in two forests, J. Appl. Meteorol., 44,



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