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Register a new userInternal wave and turbulence observations with very-high resolution temperature sensors along the Cabauw tower
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Knowledge about the characteristics of the atmospheric boundary layer are vital for the redistribution of air and suspended contents that are particularly driven by turbulent motions. Despite many modelling studies, detailed observations are still demanded of the development of turbulent exchange under stable and unstable conditions. In this paper we present an attempt to observationally detail atmospheric internal waves, under stable conditions, and associated turbulent overturning, under quasi-stable and unstable conditions. Therefore, we mounted 198 high-resolution temperature T-sensors on a cable. The instrumented cable was attached along the 213 m tall mast of Cabauw, the Netherlands, during late-summer 2017. The mast has standard and special meteorological equipment at extendable booms every 20 m in height. A sonic turbulence anemometer is at 60 m above ground. The extra, originally underwater-, T-sensor cable was suspended down from the 206-m level, temporarily for about 3 months. While in water the sensors have a response time of tw=0.4 s and drift of 0.001 degC per month, in air the response time ta=3 s is relatively slow and the apparent drift of about 0.1 degC per month relatively large. Least performance is during daytime. These T-sensor characteristics hamper quantitative atmospheric turbulence research, as it results in a relatively narrow inertial subrange of only one order of magnitude. Nevertheless, height-time images from two contrasting days show common nocturnal marginally stable density stratification supporting internal waves up to the buoyancy period of about 300 s, shear and convective deformation of the stratification over the entire 197 m range of observations.
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