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@ARTICLE{Gebler:203406,
author = {Gebler, S. and Hendricks-Franssen, Harrie-Jan and Pütz,
Thomas and Post, H. and Schmidt, Marius and Vereecken, H.},
title = {{A}ctual evapotranspiration and precipitation measured by
lysimeters: a comparison with eddy covariance and tipping
bucket},
journal = {Hydrology and earth system sciences},
volume = {19},
number = {5},
issn = {1607-7938},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {FZJ-2015-05349},
pages = {2145 - 2161},
year = {2015},
abstract = {This study compares actual evapotranspiration (ETa)
measurements by a set of six weighable lysimeters, ETa
estimates obtained with the eddy covariance (EC) method, and
evapotranspiration calculated with the full-form
Penman–Monteith equation (ETPM) for the Rollesbroich site
in the Eifel (western Germany). The comparison of ETa
measured by EC (including correction of the energy balance
deficit) and by lysimeters is rarely reported in the
literature and allows more insight into the performance of
both methods. An evaluation of ETa for the two methods for
the year 2012 shows a good agreement with a total difference
of $3.8\%$ (19 mm) between the ETa estimates. The highest
agreement and smallest relative differences (< $8\%)$ on a
monthly basis between both methods are found in summer. ETa
was close to ETPM, indicating that ET was energy limited and
not limited by water availability. ETa differences between
lysimeter and EC were mainly related to differences in grass
height caused by harvest and the EC footprint. The lysimeter
data were also used to estimate precipitation amounts in
combination with a filter algorithm for the high-precision
lysimeters recently introduced by Peters et al. (2014). The
estimated precipitation amounts from the lysimeter data
differ significantly from precipitation amounts recorded
with a standard rain gauge at the Rollesbroich test site.
For the complete year 2012 the lysimeter records show a 16
$\%$ higher precipitation amount than the tipping bucket.
After a correction of the tipping bucket measurements by the
method of Richter (1995) this amount was reduced to $3\%.$
With the help of an on-site camera the precipitation
measurements of the lysimeters were analyzed in more detail.
It was found that the lysimeters record more precipitation
than the tipping bucket, in part related to the detection of
rime and dew, which contribute $17\%$ to the yearly
difference between both methods. In addition, fog and
drizzle explain an additional $5.5\%$ of the total
difference. Larger differences are also recorded for snow
and sleet situations. During snowfall, the tipping bucket
device underestimated precipitation severely, and these
situations contributed also $7.9\%$ to the total difference.
However, $36\%$ of the total yearly difference was
associated with snow cover without apparent snowfall, and
under these conditions snow bridges and snow drift seem to
explain the strong overestimation of precipitation by the
lysimeter. The remaining precipitation difference (about
$33\%)$ could not be explained and did not show a clear
relation to wind speed. The variation of the individual
lysimeters devices compared to the lysimeter mean are small,
showing variations up to $3\%$ for precipitation and $8\%$
for evapotranspiration.},
cin = {IBG-3},
ddc = {550},
cid = {I:(DE-Juel1)IBG-3-20101118},
pnm = {255 - Terrestrial Systems: From Observation to Prediction
(POF3-255)},
pid = {G:(DE-HGF)POF3-255},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000355319500003},
doi = {10.5194/hess-19-2145-2015},
url = {https://juser.fz-juelich.de/record/203406},
}