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Tethered Soundings & Profiling. Cathryn Birch Ian Brooks. Radiosondes. 6 hourly launches T, p, RH, wind speed and direction Up to about 25km. SkyDoc Balloon. Filled with helium Diameter ~3m (inflated) Volume ~20 m 3 Static lift = 12 kg Dynamic lift = 1 ton @ 45 m s -1
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Tethered Soundings & Profiling Cathryn Birch Ian Brooks
Radiosondes • 6 hourly launches • T, p, RH, wind speed and direction • Up to about 25km
SkyDoc Balloon • Filled with helium • Diameter ~3m (inflated) Volume ~20 m3 • Static lift = 12 kg • Dynamic lift = 1 ton @ 45 m s-1 • Tether line mass = 6 g m-1 • 1.5 mile of tether available • 24 V winch
Basic system from Gill instruments Leeds adding: custom motion pack + GPS Mean T, RH, P CLASP aerosol probe Control, logging, and comms board Battery powered – duration ~5 hours Turbulence measurements @ 10 Hz Mean met data @ 1Hz
25 cm Pump Sensing head CLASP instrument Compact Lightweight Aerosol Spectrometer Probe • 16 channels - 0.24 to 18.5 m diameter • Flow rate 3 l/min – high sampling statistics allows 10 Hz temporal resolution – collocation with sonic anemometer • Compact (25 x 8 x 6 cm), robust, inexpensive – short inlet tube and low flow distortion, & installation in balloon/buoy instrument package and mounted on masts
winch Timed photographic record from balloon – lead fraction retrieval, cloud top imagery…
Altitude (m) T (C) RH (%) WS (m s-1) Mean meteorology profiles
SODAR (SOnic Detection And Ranging) – Scintec Phased Array • Measures the scattering of sound waves by atmospheric turbulence Provides • Backscatter • 3D mean winds • CT2, z/L, turbulent dissipation • Vertical resolution 10 m • 10-min averaged data
Inversion Entrainment zone well mixed layer Stable BL B A C Turbulence properties : CT2 Measurements from Africa A: UTC: 12:00 C: UTC: 20:00 B: UTC: 10:00