Actual evapotranspiration and precipitation measured by lysimeters: a comparison with eddy covariance and tipping bucket

• DOI: 10.5194/hess-19-2145-2015
• Publication Date: 2015-05-05T12:54:33Z
• Authors: S. Gebler; H.-J. Hendricks F...; T. Pütz; H. Post; M. Schmidt; H. Vereecken
• Keywords: Lysimeter; Water balance

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 calculated full-form Penman–Monteith equation (ETPM) for Rollesbroich site in Eifel (western Germany). The comparison measured EC (including correction energy balance deficit) lysimeters is rarely reported literature allows more insight into performance both methods. An evaluation two methods year 2012 shows good agreement total difference 3.8% (19 mm) between estimates. highest smallest relative differences (< 8%) on monthly basis are found summer. was close to ETPM, indicating that ET limited not water availability. lysimeter were mainly related grass height caused harvest footprint. data also used estimate precipitation amounts combination filter algorithm high-precision recently introduced Peters et al. (2014). estimated from differ significantly recorded standard rain gauge at test site. For complete records show 16 % higher amount than tipping bucket. After bucket method Richter (1995) this reduced 3%. With help an on-site camera analyzed detail. It record bucket, part detection rime dew, which contribute 17% yearly In addition, fog drizzle explain additional 5.5% difference. Larger snow sleet situations. During snowfall, device underestimated severely, these situations contributed 7.9% However, 36% associated cover without apparent under conditions bridges drift seem strong overestimation lysimeter. remaining (about 33%) could be explained did clear relation wind speed. variation individual devices compared mean small, showing variations up 3% 8% evapotranspiration.