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Precision CO 2 on Short towers A first evaluation for Loobos-NL Bart Kruijt and Jan Elbers Slide 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 Slide 3 This talk: a preliminary analysis for Loobos: functioning Error Spatial consistency Plans for use of data Slide 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! Slide 5 Full record top level at Loobos with error bars Slide 6 Slide 7 Slide 8 Day AND night! Slide 9 Other sites? Finland: majadas +0.4 -0.5 Nov -07Jun -08 Slide 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 Slide 11 Cabauw Loobos Slide 12 Slide 13 Slide 14 Difference Cabauw - Loobos Cabauw Loobos North South East West Amateuristic analysis asking for modellers! Slide 15 Compare: Majadas - La Muela Le Bray Puy de Dome Tharandt Heghatsal Hyyttiala Pallas all together! Slide 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? Slide 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?