From davis@essc.psu.edu Tue Oct 23 22:15:14 2001 Date: Tue, 2 Oct 2001 12:43:37 -0400 (Eastern Daylight Time) From: Ken Davis To: pbakwin@cmdl.noaa.gov Cc: oxelson@ucar.edu, scw@io.harvard.edu Subject: atmospheric observing plan comments I would approach the NACP atmospheric observations plan this way: I have added a few words about [co2] on AmeriFlux towers. Ken Kenneth J. Davis Department of Meteorology email: davis@essc.psu.edu The Pennsylvania State University phone: +1-814-863-8601 512 Walker Building fax: +1-814-865-3663 University Park, PA 16802-5013 http://www.meteo.psu.edu/~davis U.S.A. http://cheas.psu.edu -------- The program of atmospheric observations will proceed with a three major elements: 1) a minimum-density continent-wide [co2] observation network to greatly reduce the uncertainty in the net flux of co2 from the North American continent and work towards seasonal and regional net fluxes; 2) a regional study, with both long-term observations and an intensive field campaign, designed to test the density of observations and modeling tools needed to determine regional net co2 fluxes given simple terrain and relatively large fluxes; 3) a regional study, with both long-term observations and an intensive field campaign, to examine how to extend atmospheric [co2] budget methods of determining regional net co2 fluxes to mountainous terrain. Continental-scale boundary layer co2 mixing ratio data can be obtained in a cost-effective manner by enhancing the precision and accuracy of the measurement currently being made at AmeriFlux sites. These sites typically maintain continuous co2 flux measurements, but not highly-calibrated co2 mixing ratio measurements. Other trace gas measurements, especially CO and CH4, should also be added to these sites. These tower-based measurements can support approach (1) above, creating continental boundary layer data at moderate spatial resolution. A limited number of airborne profiling locations would provide a strong complement to this surface based network.