Using nocturnal cold air drainage flow to monitor ecosystem processes in complex terrain

Abstract

This paper presents initial investigations of a new approach to monitor ecosystem processes in complex terrain on large scales. Metabolic processes in mountainous ecosystems are poorly represented in current ecosystem monitoring campaigns because the methods used for monitoring metabolism at the ecosystem scale (e.g., eddy covariance) require flat study sites. Our goal was to investigate the potential for using nocturnal down-valley winds (cold air drainage) for monitoring ecosystem processes in mountainous terrain from two perspectives: measurements of the isotopic composition of ecosystem-respired CO₂ (~13CER) and estimates of fluxes of CO₂ transported in the drainage flow. To test if this approach is plausible, we monitored the wind patterns, CO₂ concentrations, and the carbon isotopic composition of the air as it exited the base of a young (~40-yr-old) and an old (>450-yr-old) steeply sided Douglas-fir watershed.

Citation

Pypker, Thomas G.; Unsworth, Michael H.; Mix, Alan C.; Rugh, William; Ocheltree, Troy; Alstad, Karrin; Bond, Barbara J. 2007. Using nocturnal cold air drainage flow to monitor ecosystem processes in complex terrain. Ecological Applications. 7(3): 702-714