Julio Tóta*, David Roy Fitzjarrald**, Ralf M. Staebler***, Ricardo K. Sakai**,Edwin Keizer*

1. - JRG 2 meter above ground 2D North 75m 2D East 2D West 2D Tower 75m 2D South Observational evidence of Subcanopy Drainage flow in Amazonia Julio Tóta*, David Roy Fitzjarrald**, Ralf M. Staebler***, Ricardo K. Sakai**,Edwin Keizer* * LBA Project Office, INPA, Manaus AM, tota@inpa.gov.br ** Jungle Research Group, University at Albany, SUNY,, fitz@asrc.cestm.albany.edu *** ARQP, Meteorological Service of Canada, Toronto ON., ralf.staebler@ec.gc.ca Is well know the systematic error from measurements using Eddy Covariance methodology over complex terrain and vegetation. Have been demonstrated a significant net advective flux at night by field experiments [Aubinet et al., 2003; Turnipseed et al., 2003; Staebler and Fitzjarrald, 2004]. The goal of this work is to evaluate qualitative and quantitative the contribution of the Subcanopy horizontal transport in the Amazon Ecosystem Carbon Balance. We used an very fine methodology (called Draino System) to measure Subcanopy wind and CO2 field and estimate horizontal transport of CO2 and its importance on the ecosystem carbon balance. The results indicate that the system was able to capture an consistent and persistent wind field at night following flow direction topography obtained from high resolution SRTM image over the local of the measurements. On this nights about 60% of the time the wind was calm (u* < 0.25). The NEE + Storage data from CD-10 group was on average, for the first period evaluate (Jul-Ago/2003), 5.5954 micromol/m2/s, and total ecosystem respiration was 8.2182 micromol/m2/s, indicating an difference of the 2.2628 micromol/m2/s (missing). The results from Draino System indicate an horizontal transport of the 1.5169 micromol/m2/s, for the same period. An second period (Oct/2004 til Jan/2005) indicated missing differences of the 1.7876 micromol/m2/s, while Draino System the horizontal transport was 1.05 micromol/m2/s. This results show the importance of Subcanopy Horizontal transport on the Amazon carbon balance for Flona Tapajos LBA Site. RESULTS The system was able to capture day and night information necessary to estimate the horizontal transport (advection). The requisite to calculate horizontal transport terms, i.e., scalar horizontal gradient and persistent wind field direction were capture by the Draino system. SUBCANOPY HORIZ. GRADIENTS SUBCANOPY CO2 PROFILE DOY 200/2003 EXPERIMENTAL AND METODOLOGY LOCALIZATION: An typical daily data obtained from Draino System Horizontal Transport (Advection): The subcanopy wind field was persistent with prevailing notheast/southeast direction similar topography locally (figure 7). We have been used two data analyses period (fase 1 - dry and fase 2 - wet) to estimate the horizontal transport. The values present variations between night and day of the -20 to 20 mmol/m2/s Eddy Flux, and most significant of the -10 to 10 mmol/m2/s horizontal flux, for both periods. The JRG Draino data are being collected about 60 km south of Santarém, Pará, Brazil. The data set will be useful to extend the study to the topographical effects of a large nearby river, a large escarpment, and a slope opposing the prevailing winds. The maps indicate the local of the meteorological tower on a flat plateau that sloped gently to the northwest and its irregular local topography. The Old Growth Site is only a few kilometers from the Tapajos escarpment and may experience drainage flows towards the west. The draino system instruments were chosen to help in identifying some possible topographical effects, for example air shed drainage from the Old Growth site to the river (specifically Jamaraqua) escarpment. The night average CO2 flux balance indicate that the subcanopy transport was significant for both periods studied. Average nighttimes for the fase 1, the NEE (eddy + storage) was 8.2182 while ecosystem respiration was 5.5954 mmol/m2/s, i.e., CO2 net missing of the 2.6227 mmol/m2/s against 1.5169 mmol/m2/s from the horizontal contribution. For the fase 2, the values were NEE of the 7.8121, ecosystem respiration 6.0245, with CO2 net missing of the 1.7876 mmol/m2/s, and the horizontal transport was 1.0803 mmol/m2/s. SUBCANOPY SYSTEM ARRAY CONCLUSION : As demonstrated by several recents experiments, there is nocturnal flux underestimation by eddy flux measurements. We have implemented, for the first time in the tropical rain forest, a system for direct observation of the subcanopy wind and CO2 fields, to determine locally the importance horizontal transport in the carbon ecosystem balance. Our results indicated, by direct observation, an evidence that horizontal transport should be account for the carbon balance in the Flona Tapajos LBA site, even with gently slope topography, probably principal driven of the subcanopy wind field. The Draino system could be an strong candidate, at this site, for better screening nocturnal eddy covariance underestimate CO2 flux. Acknowledgments : Lucy Rutyra/Wofsy group, for available the km67 wind and flux data. for more information: Julio Tota tota@inpa.gov.br LBA/INPA/SUNY Manaus – Brasil – CEP.: 69083-000 phone 55 XXX 92 643 3255 fax 55 XXX 92 643 3238 REFERENCES Tota et al. 2004. Staebler, R.M., D.R. Fitzjarrald, M.J. Czikowsky and R.K. Sakai, 2001: Nocturnal CO2 fluxes and understory drainage flows. Fall Conference of the American Geophysical Union, San Francisco, CA. Staebler, R.M., D.R. Fitzjarrald, K.E. Moore, M.J. Czikowsky and O.C. Acevedo, 2000a: Topographic effects on flux measurements at Harvard Forest. 14th Symposium on Boundary Layers and Turbulence / Ninth Conference on Mountain Meteorology, Aspen, CO. Staebler, R.M., PhD Thesis. Fitzjarrald, D.R. et al. 2000. Fitzjarrald, D.R., 1984: Katabatic wind in opposing flow. J. Atm. Sc. , 41, 1143-1158. Aubinet, M., B. Heinesch and M. Yernaux, 2003. Horizontal and vertical CO2 advection in a sloping forest. Bound. Layer Meteorol. 108:397-417. 2003