Tethered Soundings & Profiling

Institute for Atmospheric ScienceSCHOOL OF EARTH AND ENVIRONMENT UNIVERSITY OF LEEDS

Tethered Soundings & Profiling

Cathryn Birch

Ian Brooks

UNIVERSITY OF LEEDS

Institute for Atmospheric ScienceSCHOOL OF EARTH AND ENVIRONMENT

Radiosondes

• 6 hourly launches• T, p, RH, wind speed and

direction• Up to about 25km

UNIVERSITY OF LEEDS


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

UNIVERSITY OF LEEDS


Basic system from Gill instrumentsLeeds 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

UNIVERSITY OF LEEDS


CLASP instrument Compact Lightweight Aerosol Spectrometer Probe

Pu

mp

Sensing head

25 cm

• 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

UNIVERSITY OF LEEDS


winch

Timed photographic record from balloon – lead fraction retrieval, cloud top imagery…

UNIVERSITY OF LEEDS


Mean meteorology profiles

T (C) WS (m s-1)RH (%)

Alti

tude

(m

)

UNIVERSITY OF LEEDS


SODAR (SOnic Detection And Ranging) – Scintec Phased Array

Provides– Backscatter– 3D mean winds

– CT2, z/L, turbulent dissipation

– Vertical resolution 10 m– 10-min averaged data

• Measures the scattering of sound waves by atmospheric turbulence

UNIVERSITY OF LEEDS


Turbulence properties : CT2

Measurements from Africa

Inversion

Entrainment zone

well mixed layer

Stable BL

A: UTC: 12:00

B: UTC: 10:00

C: UTC: 20:00

A CB

Tethered Soundings & Profiling

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