1. ECLAIRE - Bugac station
Tamás Weidinger and László Horváth
Participants:
Forest Research Institute, Budapest
Szent István University, Gödöllő
Eötvös Loránd University, Budapest
Special thinks for the participation of the measurement and micrometeorological data preparing for Zoltán Nagy, Kriszta Pinter (SZIU), Zénó Gyöngyösi, Zoltán Istenes (ELTE), Attila Eredics (University of West Hungary, Sopron)

2. Bugac Hungary (WP1)
located in Kiskunság National Park, in the Hungarian Great Plain, coordinates: 46.8 N, 18.9 E
climate is extreme temperate continental (yearly precipitation ~ 500 mm)
vegetation: semiarid sandy grassland.
manipulation: grazing ~ 0.5 cow/ha
Micrometeorological measurements from 2002

3. Enviscope (Karlsruhe type) fast response ozone for eddy ozone flux
Bugac puszta
Instrumentation
O3, NO, NO2 online gradient measurements at 2 heights
Soil emission of NO using 4 dynamic chambers (1 per hour) two automatic and two non automatic chamber
Fast response ozone measurement
CO2 flux measurement by eddy-system (SZIU)
Energy budget components and micrometeorological measurement (based on the earlier NEU protocol from SZIU)
Enviscope (Karlsruhe type) fast response ozone for eddy ozone flux

4. Chamber measurements
Dynamic chambers used in NUE program (V ~ 3 dm3) and automatic chambers from Italy (6.6 dm3) for hourly NO flux measurements.

5. Bugac site -Each instrument in operation raw dataset
-Trace gas flux calculation
under progress
HORIBA APNA and APOA 350 monitors,
for NO/NO2 gradient fluxes: 3 and 0.6 m inlets, 5-5 minute measurements with frequent data logging

7. Preliminary results – NO flux (1. Oct – 10. Dec)
Mean Values: 3.82, 1.89, 0.91 and 0,66 mgN/m2h
Non automatic dynamical
chamber
Sensitivity of soil flux to input temperature: 0.4 % per oC (Fm ≈ Fbl)

8. Non automatic chamber
Mean: 1.89
Mean: 0.91
Automatic chamber

9. Eddy covariance Ozone flux
10 Hz sampling, 30 min average despiking (4s ) linear detrending 2D coordinate rotating mV – Ozone (mg/m3) conversion covariance maximization Webb-correction (Closed path sensor)

10. Open questions
Eddy covariance
sensitivity of the ozone disk (O3 concentration, relative humidity), nighttime covariance maximization, nighttime flux variances and positive values, flux-profile relationships
Gradient method
uncertainty of the daytime gradients, choose of the universal functions, ONLY statistical investigation of the

12. O3 / Voltage ratio

13. Maximization of covariance, time delay

14. Webb-correction, real time delays

15. What is the optimal detrending?
Unstationarity of nighttime time series

16. Effect of time delay and 2D coordinate rotation

17. Daily variation of O3

18. Daily variation of O3 differences

19. Future: Continuous flux measurements
Optimal method for eddy covariance calculation
Nighttime fluxes
Statistical investigations of gradient measurements
Modeling work WRF/CMAQ
Comparison study of automatic and non automatic dynamic chamber measurements