Future climate change is expected to affect ecosystem-atmosphere CO2 exchange, particularly through the influence of temperature. To date, however, few studies have shown that differences in the response of net ecosystem CO2 exchange (NEE) to temperature among ecosystems can be explained by differences in the …
Journal: Geophysical Research Letters, Volume 31 (17): n/a-n/a (2004), ISBN . DOI: 10.1029/2004gl020490 Sites: US-Ha2, US-Los, US-NR1, US-PFa, US-WBW, US-WCr
The location of the Niwot Ridge Ameriflux site within the rocky mountains subjects it to airflows which are common in mountainous terrain. In this study, we examine the effects of some of these mesoscale features on local turbulent flux measurements; most notably, the formation of valley/mountain flows and mountain lee-side …
Journal: Agricultural And Forest Meteorology, Volume 125 (3-4): 187-205 (2004), ISBN . DOI: 10.1016/j.agrformet.2004.04.007 Sites: US-NR1
We evaluated the hypothesis that CO2 uptake by a subalpine, coniferous forest is limited by cool temperature during the growing season. Using the eddy covariance approach we conducted observations of net ecosystem CO2 exchange (NEE) across two growing seasons. When pooled for the entire growing season during …
Journal: Oecologia, Volume 134 (4): 537-546 (2003), ISBN . DOI: 10.1007/s00442-002-1131-1 Sites: US-NR1
We report measurements of the uptake of peroxyacetyl nitrate (PAN) by plant leaves at mixing ratios typical of the continental lower troposphere. PAN uptake rates between 20 and 55 pmol m−2 s−1 were measured in eight plant species at an atmospheric mixing ratio of 250 pptv. Uptake rates in all species were …
Journal: Geophysical Research Letters, Volume 30 (23): n/a-n/a (2003), ISBN . DOI: 10.1029/2003gl018578 Sites: US-NR1
We have studied the effects of local topography and canopy structure on turbulent flux measurements at a site located in mountainous terrain within a subalpine, coniferous forest. Our primary aim was to determine whether the complex terrain of the site affects the accuracy of eddy flux measurements from a practical perspective. We …
Journal: Agricultural And Forest Meteorology, Volume 119 (1-2): 1-21 (2003), ISBN . DOI: 10.1016/s0168-1923(03)00136-9 Sites: US-NR1
The U.S. carbon budget has been the focus of recent scientific debate [Fan et al., 1998; Pacala et al., 2001; Gurney et al., 2002] Even conservative estimates suggest that U.S. …
Journal: EOS, Transactions American Geophysical Union, Volume 83 (40): 445-449 (2002), ISBN . DOI: 10.1029/2002eo000314 Sites: US-NR1
We studied net ecosystem CO2 exchange (NEE) dynamics in a high-elevation, subalpine forest in Colorado, USA, over a two-year period. Annual carbon sequestration for the forest was 6.71 mol C m−2(80.5 g C m−2) for the year between November 1, 1998 and October 31, 1999, and 4.80 mol C m−2(57.6 g C m−2) …
Journal: Global Change Biology, Volume 8 (5): 459-478 (2002), ISBN . DOI: 10.1046/j.1365-2486.2002.00480.x Sites: US-NR1
Components of the energy budget were measured above a subalpine coniferous forest over two complete annual cycles. Sensible and latent heat fluxes were measured by eddy covariance. Bowen ratios ranged from 0.7 to 2.5 in the summer (June–September) depending upon the availability of soil water, but were considerably higher (∼3–6) …
Journal: Agricultural And Forest Meteorology, Volume 110 (3): 177-201 (2002), ISBN . DOI: 10.1016/s0168-1923(01)00290-8 Sites: US-NR1
Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (Rd) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity …
Journal: Oecologia, Volume 114 (4): 471-482 (1998), ISBN . DOI: 10.1007/s004420050471 Sites: US-NR1