edu.ucar.opensky::articles:15303 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T15:03:01.733723 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d78053n8 Soil, plant, and transport influences on methane in a subalpine forest under high ultraviolet irradiance 2009-07-30T00:00:00Z publication https://n2t.org/ark:/85065/d78053n8 https://doi.org/10.5194/bg-6-1311-2009 Bowling, D. author Miller, J. author Rhodes, M. author Burns, Sean author Monson, R. author Baer, D. author UCAR/NCAR - Library publisher Recent studies have demonstrated direct methane emission from plant foliage under aerobic conditions, particularly under high ultraviolet (UV) irradiance. We examined the potential importance of this phenomenon in a high-elevation conifer forest using micrometeorological techniques. Vertical profiles of methane and carbon dioxide in forest air were monitored every 2 h for 6 weeks in summer 2007. Day to day variability in above-canopy CH₄ was high, with observed values in the range 1790 to 1910 nmol mol⁻¹. High CH₄ was correlated with high carbon monoxide and related to wind direction, consistent with pollutant transport from an urban area by a well-studied mountain-plain wind system. Soils were moderately dry during the study. Vertical gradients of CH₄ were small but detectable day and night, both near the ground and within the vegetation canopy. Gradients near the ground were consistent with the forest soil being a net CH₄ sink. Using scalar similarity with CO₂, the magnitude of the summer soil CH₄ sink was estimated at ~1.7 mg CH₄ m⁻ ² h⁻¹, which is similar to other temperate forest upland soils. The high-elevation forest was naturally exposed to high UV irradiance under clear sky conditions, with observed peak UVB irradiance >2 W m⁻ ². Gradients and means of CO₂ within the canopy under daytime conditions showed net uptake of CO₂ due to photosynthetic drawdown as expected. No evidence was found for a significant foliar CH₄ source in the vegetation canopy, even under high UV conditions. While the possibility of a weak foliar source cannot be excluded given the observed soil sink, overall this subalpine forest was a net sink for atmospheric methane during the growing season. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Authors 2009. This work is distributed under the Creative Commons Attribution 3.0 License None eng geoscientificInformation