Abstract
With the objective of quantifying turbulent sensible QH and latent QE heat fluxes above a suburban reservoir, a micrometeorological turbulence measurement campaign using the eddy covariance technique was carried out between June and November 2012 on the Baldeneysee, an artificial lake (2.64 km2 area with up to 4-m depth) located in Germany. The study was conducted at this site because there is little information on this type of lake and the findings are important for the local water management system. Sensible heat fluxes show a mean diurnal course with maximum positive values during the early morning hours (maximum = +31.3 W m−2) and negative values in the afternoon (minimum = −12.3 W m−2). During daytime, average QH/Q* ratios (where Q* is the radiation balance) are, in general, smaller than 0.20. Sensible heat fluxes are especially affected by the product of wind speed and water–air temperature difference, as well as the magnitude of global radiation. In contrast, mean hourly values of QE are, on average, positive over the whole day, with an absolute spread between +175.1 and −0.8 W m−2. During daytime in summer, 74% of the radiation balance is transferred via QE. The measurement values show that during two summer days, 3.72 and 2.84 mm day−1 of water could be evaporated, whereas during two measurement days in autumn, evaporation rates of only 1.36 and 0.94 mm day−1 were registered. The magnitude of QE is mainly affected by four main parameters: the product of wind speed and vapor pressure deficit, followed by the magnitude of global radiation and water temperature.
Denotes Open Access content.
Publisher’s Note: This article was revised on 1 July 2015 to include the open access designation that was added after initial publication.
