A Design for Unattended Monitoring of Carbon Dioxide on a Very Tall Tower

Abstract

Unattended measurements of carbon dioxide (CO 2 ) mixing ratio at three altitudes up to 496 m above the surface on a television transmitter tower in the southeastern United States have been made for a period of 4 yr. This report describes the design of the automatic tower measuring system in detail. A nondispersive infrared (NDIR) analyzer is used to measure the CO 2 concentration continuously. Real-time control and data collection uses a PC 486 running under the multitasking operating system QNX. The CO 2 data show strong diurnal and seasonal variations, and large vertical gradients. A comparison of this study's continental tower data with data from ''background'' sites should provide a strong constraint for regional and global models of terrestrial CO 2 fluxes.