@article{675345a2b5f748bf887dde8f4944a680,
title = "Earlier snowmelt reduces atmospheric carbon uptake in midlatitude subalpine forests",
abstract = "Previous work demonstrates conflicting evidence regarding the influence of snowmelt timing on forest net ecosystem exchange (NEE). Based on 15 years of eddy covariance measurements in Colorado, years with earlier snowmelt exhibited less net carbon uptake during the snow ablation period, which is a period of high potential for productivity. Earlier snowmelt aligned with colder periods of the seasonal air temperature cycle relative to later snowmelt. We found that the colder ablation-period air temperatures during these early snowmelt years lead to reduced rates of daily NEE. Hence, earlier snowmelt associated with climate warming, counterintuitively, leads to colder atmospheric temperatures during the snow ablation period and concomitantly reduced rates of net carbon uptake. Using a multilinear-regression (R2 = 0.79, P < 0.001) relating snow ablation period mean air temperature and peak snow water equivalent (SWE) to ablation-period NEE, we predict that earlier snowmelt and decreased SWE may cause a 45% reduction in midcentury ablation-period net carbon uptake.",
keywords = "carbon uptake, net ecosystem exchange, snow ablation period",
author = "Winchell, {Taylor S.} and Barnard, {David M.} and Monson, {Russell K.} and Burns, {Sean P.} and Molotch, {Noah P.}",
note = "Funding Information: This material is based upon work supported by the U.S. National Science Foundation (NSF) Graduate Research Fellowship (NSF grant DGE 1144083), the NSF-U.S. Department of Agriculture (USDA) joint program for Water Sustainability and Climate (USDA grant: 2012-67003-19802), and the NSF Hydrological Sciences Program (NSF Grant: EAR1141764). Data collection was funded by the U.S. Department of Energy (DOE), the USDA, and the NSF Niwot Ridge Long-Term Ecological Research program. The US-NR1 AmeriFlux site is supported by the DOE Office of Science through the AmeriFlux Management Project (AMP) at Lawrence Berkeley National Laboratory under award 7094866. We offer thanks to Peter Blanken and all others involved in the AmeriFlux data collection efforts. Additionally, we are very thankful to David Schimel and one anonymous reviewer for their constructive reviews of the manuscript. All data used are listed in the supporting information and can be found at http://urquell.colorado.edu/data_ameriflux/ and http://www.wcc.nrcs.usda.gov/nwcc/site?sitenum=663. Publisher Copyright: {\textcopyright}2016. American Geophysical Union. All Rights Reserved.",
year = "2016",
month = aug,
day = "16",
doi = "10.1002/2016GL069769",
language = "English (US)",
volume = "43",
pages = "8160--8168",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "15",
}