2. Eddy Covariance John Knowles University of Colorado Department of Geography INSTAAR

3. www.esrl.noaa.gov

4. Airflow PBL characterized by turbulent airflow Can be imagined as the horizontal flow of numerous rotating eddies Each eddy has 3D components including a vertical wind component Burba & Anderson, 2006

5. Sonic Anemometer Infrared gas analyzer (IRGA)

6. FLUX Movement per unit area per unit time Evaporation flux mg (mol) H 2 O m -2 s -1 Latent Heat Flux Wm -2

7. Eddies at one point Each parcel of air has a particular… 1.trace gas concentration 2.temperature 3.humidity Burba & Anderson, 2006

8. Vertical Flux (F) Latent Heat FluxEddy Flux Reynolds Decomposition

12. Footprint ‘Field of view’ Area which contains the sources and sinks contributing to a certain measurement point Reflects the influence of the surface on the measured turbulent flux Burba & Anderson, 2006

13. Inverse Gaussian plume model Schuepp et al., 1990

14. Ecosystem scale! (m)

15. Major Assumptions Point measurements represent an upwind area Footprint contains only area of interest Flux is fully turbulent - vertical transfer done mostly by eddies