study of the terrestrial carbon cycle is currently data limited.
One approach to increasing the density of data over the continents is
to instrument eddy-covariance flux towers with well-calibrated CO2
mixing ratio measurements. More than two hundred such towers are
currently being operated at continental sites around the globe.
Most of these towers, however, while measuring CO2 mixing ratios at
high frequency, continuously, and with good relative precision, do not
have carefully calibrated long-term mixing ratio measurements.
Similarly it has been thought that mixing ratio measurements in the
atmospheric surface layer, the lowest portion of the atmospheric
boundary layer, would be too close to strong sources and sinks to be
useful for studying the carbon cycle via atmospheric budget or inverse
studies. Methods exist, however, for both precise calibration of
flux tower mixing ratio measurements and careful interpretation of
surface layer data. A relatively low-cost, high-precision CO2
mixing ratio measurement system has been developed in collaboration
with NCAR-ATD, to support inverse analyses of the terrestrial carbon
balance at regional to continental scales.
The above map was prepared based on
IDL code written by A.S. Denning of Colorado State University.
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