Tethered Lifting Systems
Kites and balloon-borne systems have been used for atmospheric research since 1749, and Balsley (2008) provides a comprehensive review of this history. These platforms can transport probes aloft to sample the lowest atmosphere. Even though weather balloons typically carry radiosondes that measure average values of temperature, pressure, winds, and humidity, tethered systems can carry five-hole and seven-hole pitot tubes as well as hot wire and cold wire anemometers. Such platforms have enabled important fundamental insights into boundary-layer dynamics, especially stable boundary layers, because of the ability to sample vertical profiles of thin layers in the atmosphere (Frehlich et al. 2003; Muschinski et al. 2004; Frehlich et al. 2006; Balsley et al. 2006, 2007). As discussed here and shown in Figure 16, in “Hot wire, cold wire, hot film, cold film anemometers,” tethered systems have been used to sample turbulence dissipation rates as well as wind speed deficits in wind turbine wakes (Lundquist and Bariteau 2015).
Instrumentation common to Tethered Lifting Systems