Basic and extensible post-processing of eddy covariance flux data with REddyProc
<p>With the eddy covariance (EC) technique, net fluxes of carbon dioxide (CO<sub>2</sub>) and other trace gases as well as water and energy fluxes can be measured at the ecosystem level. These flux measurements are a main source for understanding biosphere–atmosphere interaction...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-08-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/5015/2018/bg-15-5015-2018.pdf |
| Summary: | <p>With the eddy covariance (EC) technique, net fluxes of carbon dioxide
(CO<sub>2</sub>) and other trace gases as well as water and energy fluxes can be
measured at the ecosystem level. These flux measurements are a main source
for understanding biosphere–atmosphere interactions and feedbacks through
cross-site analysis, model–data integration, and upscaling. The raw fluxes
measured with the EC technique require extensive and laborious data
processing. While there are standard
tools<sup>1</sup> available in an open-source environment for
processing high-frequency (10 or 20 Hz) data into half-hourly
quality-checked fluxes, there is a need for more usable and extensible tools
for the subsequent post-processing steps. We tackled this need by developing
the <span style="" class="text typewriter">REddyProc</span> package in the cross-platform language R that provides
standard CO<sub>2</sub>-focused post-processing routines for reading
(half-)hourly data from different formats, estimating the <i>u</i><sub>*</sub>
threshold, as well as gap-filling, flux-partitioning, and visualizing the
results. In addition to basic processing, the functions are extensible
and allow easier integration in extended analysis than current tools. New
features include cross-year processing and a better treatment of
uncertainties. A comparison of <span style="" class="text typewriter">REddyProc</span> routines with other
state-of-the-art tools resulted in no significant differences in monthly and
annual fluxes across sites. Lower uncertainty estimates of both <i>u</i><sub>*</sub> and
resulting gap-filled fluxes by 50 % with the presented tool were achieved
by an improved treatment of seasons during the bootstrap analysis. Higher
estimates of uncertainty in daytime partitioning (about twice as high)
resulted from a better accounting for the uncertainty in estimates of
temperature sensitivity of respiration. The provided routines can be easily
installed, configured, and used. Hence, the eddy covariance community will
benefit from the <span style="" class="text typewriter">REddyProc</span> package, allowing easier integration of
standard post-processing with extended analysis.</p>
<p><sup>1</sup><a href="http://fluxnet.fluxdata.org/2017/10/10/toolbox-a-rolling-list-of-softwarepackages-for-flux-related-data-processing/" target="_blank">http://fluxnet.fluxdata.org/2017/10/10/toolbox-a-rolling-list-of-softwarepackages-for-flux-related-data-processing/</a>,
last access: 17 August 2018</p> |
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| ISSN: | 1726-4170 1726-4189 |