HR: 1340h
AN: B43D-1592    [Abstracts]
TI: The Second "Ring of Towers": Over-sampling the Mid Continent Intensive region CO2 mixing ratio?
AU: * Richardson, S
EM: srichardson@psu.edu
AF: Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802,
AU: Miles, N
EM: nmiles@met.psu.edu
AF: Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802,
AU: Davis, K
EM: davis@met.psu.edu
AF: Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802,
AU: Crosson, E
EM: eric@picarro.com
AF: Picarro, Inc., 480 Oakmead Parkway, Sunnyvale, CA 94085,
AU: Denning, S
EM: denning@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, 1371 Campus Delivery, Fort Collins, CO 80523,
AU: Zupanksi, D
EM: zupanski@cira.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, 1371 Campus Delivery, Fort Collins, CO 80523,
AU: Uliasz, M
EM: marek@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, 1371 Campus Delivery, Fort Collins, CO 80523,
AB: A central barrier preventing the scientific community from understanding the carbon balance of the continent is methodological; it is technically difficult to bridge the gap in spatial scales that exists between the detailed understanding of ecological processes that can be gathered via intensive local field study, and the overarching but mechanistically poor understanding of the global carbon cycle that is gained by analyzing the atmospheric CO2 budget. The NACP's Midcontinental Intensive (MCI) study seeks to bridge this gap by conducting a rigorous methodological test of our ability to measure the terrestrial carbon balance of the upper Midwest. A critical need in bridging this gap is increased data density. A primary goal of the project is to increase the regional atmospheric CO2 data density so that 1) atmospheric inversions can derive well-constrained regional ecosystem carbon flux estimates and 2) the trade off between data density and accuracy of the flux estimates can be determined quantitatively using field observations, thus providing guidance to future observational network designs. Our work adds a regional network of five communications-tower based atmospheric CO2 observations to the planned long-term atmospheric CO2 observing network (tall towers, flux towers and aircraft profiles) in the midcontinent intensive region. Measurements began in April–June 2007, If the measurements are shown to be spatially dense enough to over sample the CO2 mixing ratio, the experiment will provide an upper bounds on the density of measurements required to produce the most accurate flux possible with current atmospheric inversions. The five sites for "Ring 2" and deployment dates are Centerville, IA (Apr 07), Round Lake, MN (May 07), Kewanee, IL (Apr 07), Mead, NE (Apr 07), Galesville, WI (June 07). Two heights are sampled at each tower (30 m AGL and between 110 and 140 m AGL). More details are available at www.ring2.psu.edu. In addition, two systems in PSU's network of well-calibrated CO2 mixing ratio measurements deployed at Ameriflux towers are within the midcontinental region: Ozark, MO (30 m AGL) and Mead, NE (3-6 m AGL) (www.amerifluxco2.psu.edu). The instruments chosen for the Ring 2 deployment are Picarro Inc., Cavity Ring-Down Spectroscopy (CRDS) instruments. One advantage of the CRDS instruments is the reduced need for calibration compared to the systems used in PSU's Ameriflux CO2 network which are calibrated every four hours using four calibration tanks. Although the long-term stability is not exactly known, tests have shown accuracy to within 0.2 ppm on a monthly time scale without additional calibration. Preliminary results show spatial differences in daytime CO2 across the ring that are as large as 40 ppm, and highly variable in time. We will present observations and preliminary interpretation of these data.
UR: http://www.ring2.psu.edu
DE: 0428 Carbon cycling (4806)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting