Policy Initiative:
Constraining Regional CO₂and Hg Fluxes

A central task will begin to establish a regional observing network that can provide continuous long-term air quality data at multiple heights above the Earth ’s surface
(e.g.., 0-500 m).  AIRMAP has been measuring atmospheric carbon dioxide (CO₂) and total gas-phase mercury (Hg = Hg⁰ + Hg²⁺) at ground level in eastern New Hampshire since January 2002 and November 2003, respectively. Our proposed measurement network together with modeling tools will provide accurate estimates of the sources and sinks of these gases, inform econometric models, and provide a solid foundation to formulate policy perspectives.

Stationary surface monitoring of ambient CO₂ has clearly defined its seasonality and inter-annual variability in the global rate of CO₂ increase in the Earth ’s atmosphere [ Denning et al ., 1995; Conway et al ., 1994]. Several different lines of reasoning have been used to arrive at the hypothesis that there is a large Northern Hemispheric mid-latitude sink for CO₂ [ Tans et al ., 1990; Conway et al ., 1994; Fan et al ., 1999]. However, the various types of models employed ( i.e., inverse, forward, or global) to establish this hypothesis have relied heavily on data obtained from remote sites to avoid confounding effects from continental sources and sinks of CO₂. One exception is the ongoing measurements at Harvard Forest in central Massachusetts where eddy covariance measurements are being used to determine factors controlling long- and short-term sequestration of atmospheric CO₂ in a mid-latitude forest [ Barford et al ., 2001].

Ultimately, our proposed observing network will provide an ideal data set for regional 3-d model validation and evaluation, and also yield accurate estimates of trans-boundary fluxes and export from the Northeast to the Northern Hemisphere.