Observational Evidence of Sub-Canopy Drainage Flow in Amazonia
Silva, INPA, email@example.com
Fitzjarrald, -- Ralf
Staebler, -- Ricardo
Systematic errors from measurements using the eddy covariance methodology over complex terrain and vegetation are a recognized problem. The goal of this work was to evaluate qualitatively and quantitatively the contribution of the sub-canopy horizontal transport in the Amazon ecosystem carbon balance. We used a very fine scale methodology (called the Draino System) to measure sub-canopy wind and CO2 fields in order to estimate horizontal transport of CO2 and its importance on the ecosystem carbon balance. The results indicated that the system was able to capture a consistent and persistent wind field at night following the topography obtained from high resolution SRTM image over the locale of the measurements. At night, about 60% of the time the wind was calm (u* < 0.25). For the first period evaluated (Jul-Ago/2003), the NEE + storage data from the CD-10 group was, on average, 5.6 micromol m-2 s-1, and total ecosystem respiration was 8.2 micromol m-2 s-1, indicating an difference of the 2.3 micromol m-2 s-1 (missing). The results from Draino System indicate an horizontal transport of the 1.5 micromol m-2 s-1 for the same period. During a second period (Oct/2004 until Jan/2005) the missing differences were 1.8 micromol m-2 s-1, while the Draino System indicated a horizontal transport of the 1.1 micromol m-2 s-1. These results show the importance of sub-canopy horizontal transport to the carbon balance for the Flona Tapajos LBA Site.