Extended Abstract (244K)6.2
Surface renewal determination of scalar fluxes over an old-growth forest
PAPER WITHDRAWN
Donatella Spano, University of Sassari, Sassari, Italy; and P. Duce, R. L. Snyder, K. T. Paw U, and M. Falk
The surface renewal (SR) method for estimating fluxes from canopies involves high frequency measurements of scalar parameters. The high frequency data are analyzed for ramp-like characteristics and the amplitude and inverse ramp frequency are used in basic energy or mass conservation equations to estimate fluxes. In previous papers, good results were reported for estimating sensible (H) and latent heat (LE) flux density and CO2 flux density (Fc) using an unfiltered, data set of 10 Hz wind speed, temperature and humidity data collected above a 65 m tall, old-growth coniferous forest at the Wind River crane site in Washington State. In this paper, we report on an extensive data set from the same site, where the data were filtered to remove data measured when the air came from a direction with inadequate fetch or through the crane. Data fluctuations were recorded using a Gill 3-D sonic anemometer and Licor 6262 infrared gas analyzer mounted at 70 m height. Estimates of eddy covariance H, lE and Fc were corrected for temperature and density fluctuations. The results indicate that the SR method provides a simple, low-cost method to estimate scalar fluxes without the need to measure stability or wind speed. Therefore, the SR method can be used to estimate scalar fluxes during periods with missing data or when more expensive equipment is unavailable.
Session 6, Carbon dioxide exchange Part 1: forests
Wednesday, 22 May 2002, 8:45 AM-1:15 PM
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