1. Precision CO 2 on Short towers A first evaluation for Loobos-NL Bart Kruijt and Jan Elbers

2. introduction For overview of activity 2.7, See talk Tuula Aalto Idea of ‘short tower CO 2 ’: Low cost, higher density Concurrent with (CarboEurope) flux and meteo sites Would allow ‘virtual tall tower approach’ (modified flux- gradient) Regional inversion, local interpretation of profiles and temporal dynamics

3. This talk: a preliminary analysis for Loobos: functioning Error Spatial consistency Plans for use of data

4. AIRCOA on-line majadas Loobos was last in getting operational: -low power -only GPRS connection, no internet -Code needed substantial rewriting - Loobos was the FIRST in going on-line! - we have a beautiful moderate-cost system now!

5. Full record top level at Loobos with error bars

8. Day AND night!

9. Other sites? Finland: majadas +0.4 -0.5 Nov -07Jun -08

10. URAS - LiCor NCAR specified 0.1- 0.2 ppm precision. Why are we doing worse? -Temperature and humidity ranges larger (less continental, no cabins) -Reference gas (dry) shares part of tubing with sample (wet) -Pressure gradient from reference to IRGA  vulnerability to leaks

11. Cabauw Loobos

14. Difference Cabauw - Loobos Cabauw Loobos North South East West Amateuristic analysis asking for modellers!

15. Compare: Majadas - La Muela Le Bray – Puy de Dome Tharandt – Heghatsal Hyyttiala – Pallas … all together!

16. Plans for analysis (Loobos, all sites) (limited time) Improve accuracy (??) Explore extrapolation to CBL (‘VTT’) Explore use in regional inversion (RAMS-VU) in Dutch CO 2 budgetting study Explore use in micrometeorology  can the rich information on (all) fluxes, profiles and meteo help in vertical scaling, in regional modelling and inversion?

17. Conclusion © Wageningen UR -Accuracy so far + / - 0.5 ppm - TBI ? -Beautiful in-canopy gradients waiting for analysis -Useful data for use in (regional) inversions?