Temperature-gradient microstructure data; Balbina Reservoir, Brazil, 1-20 July 2013. Profile data with ~1 mm sampling intervals

As a component of a physical limnology experiment in Balbina Reservoir, Brazil, temperature-gradient microstructure profiles were obtained with the self-contained autonomous microstructure profiler (SCAMP, designed and made by Precision Measurement Engineering) in July 2013. This instrument provides not only high resolution temperature and conductivity profiles, but also internally differentiates the temperature signal to obtain temperature gradients from which the rate of dissipation of turbulent kinetic energy can be obtained. Dissipation rates are considered indicative of the extent of turbulence in a water body and are used to compute the coefficient of eddy diffusivity and gas transfer velocities. For this experiment whose goals included understanding physical controls on gas transfer velocities, profiles were taken in upcast mode in the upper 10 m with a rise speed close to 0.1 m s-1 and sampling frequency of 100 Hz enabling 1 mm vertical resolution. The instrument descended away from the boat on deployment, dropped a weight, and rose away from the boat. The sensor’s passing through the air-water interface was identified by temperature rapidly decreasing by 0.05oC; data above that depth were not used. Data were obtained in blocks of 6 to 10 profiles from early morning through late evening so that variability over diel cycles could be described. Details on the instrument and data analysis are in MacIntyre et al. (1999) and Tedford et al. (2014). Time series meteorological and temperature data provided context and have also been archived on KNB. Maclntyre, S., K.M. Flynn, R. Jellison, and J.R. Romero. 1999. Boundary mixing and nutrient flux in Mono Lake, CA. Limnol. Oceanogr. 44: 512-529. Tedford, E. W. S. MacIntyre, S. D. Miller, and M. J. Czikowsky. 2014. Similarity scaling of turbulence in a small temperate lake during fall cooling. J. Geophys. Res. Oceans. 119. doi:10.1002/2014JC010135.