Document: GRA-3-63-26

Good agreement between open top chamber and eddy covariance measurements of net ecosystem CO₂ exchange, in a Florida scrub-oak ecosystem.

DORE, S.* ¹, G.HYMUS ², D.JOHNSON ², P.DIJKSTRA ², C.R.HINKLE ⁴, R.VALENTINI ¹ and B.DRAKE ³

University of Tuscia, Viterbo, Italy. ¹
Smithsonian Environmental Research Center, Kennedy Space Center, FL 32899. ²
Smithsonian Environmental Research Center, Edgewater, MD 21037. ³
Dynamac Corporation, Kennedy Space Center, FL 32899. ⁴

Abstract:
Over a period of five days in August 1997 simultaneous measurements of net ecosystem carbon exchange (NEE) were made, using open top chambers (OTC's) and eddy covariance. This experiment was conducted in an evergreen scrub-oak palmetto ecosystem in Florida, on a site that had burned 15 months previously. Although there were differences between the microclimate inside and outside the OTC's, maximum rates of day NEE, and night NEE were in good agreement for the two techniques. At high PPFD, NEE was unaffected by measurement technique. At low PPFD, NEE was higher in the OTC's. The response of NEE to air temperature was in good agreement for the two techniques, with a broad temperature optimum for NEE between 35 and 42C.

Keywords: Open Top Chambers, Eddy Covariance, Net Ecosystem CO₂ Exchange.

This abstract is being presented at: 1:30 PM in session:
Oral Session #50: Plant Gas Exchange.