Development of a balloon-borne stabilized platform for measuring radiative flux profiles in the atmospheric boundary layer
A stabilized platform has been developed to carry broadband short-wave and long-wave radiometric sensors on the tether line of a small tethered balloon that ascends through atmospheric depths of up to 1.5 km to obtain vertical profiles of radiative flux and flux divergence for evaluating atmospheric radiative transfer models. The Sky Platform was designed to keep the radiometers level despite unpredictable movements of the balloon and tether line occasioned by turbulence and wind shear. The automatic control loop drives motors, gears, and pulleys located on two of the vertices of the triangular frame to climb the harness lines to keep the platform level. Radiometric sensors, an electronic compass, and an on-board data acquisition system make up the remainder of the Sky Platform. Because knowledge of the dynamic response of the tether line-platform system is essential to properly close the automatic control loop on the Sky Platform, a Motion Sensing Platform (MSP) was developed to fly in place of the Sky Platform on the tether line to characterize the Sky Platform's operating environment. This unstabilized platform uses an array of nine solid-state linear accelerometers to measure the lateral and angular accelerations, velocities, and displacements that the Sky Platform will experience. This paper presents field performance tests of the Sky and Motion Sensing Platforms, as conducted at Richland, Washington, on February 17, 1993. The tests were performed primarily to characterize the stabilization system on the Sky Platform. Test flights were performed on this cold winter day from 1400 to 1800 Pacific Standard Time (PST). During this period, temperature profiles were near the dry adiabatic lapse rate. Flights were made through a jet wind speed profile having peak wind speeds of 7 m/s at a height of 100 m AGL. Wind directions were from the northwest. All flights were performed as continuous ascents, rather than ascending in discrete steps with halts at set altitudes.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6473490
- Report Number(s):
- PNL-SA-21966; CONF-9303122-2; ON: DE93013186
- Resource Relation:
- Conference: 3. ARM science team meeting, Norman, OK (United States), 1-5 Mar 1993
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EARTH ATMOSPHERE
RADIATIVE COOLING
RADIOMETERS
STABILIZATION
ACCELEROMETERS
BALLOONS
LONG WAVE RADIATION
OSCILLATIONS
PORTABLE EQUIPMENT
TURBULENCE
WIND
AIRSHIPS
COOLING
ELECTROMAGNETIC RADIATION
EQUIPMENT
MEASURING INSTRUMENTS
RADIATION DETECTORS
RADIATIONS
RADIOWAVE RADIATION
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