Note: Active optical detection of cloud from a balloon platform

Area of Science:

• Atmospheric Science
• Optical Instrumentation
• Cloud Physics

Background:

• Accurate atmospheric cloud detection is crucial for weather forecasting and climate studies.
• Existing methods may be limited in daytime operation or portability.
• Balloon-borne platforms offer unique vantage points for atmospheric measurements.

Purpose of the Study:

• To develop and describe a novel, lightweight, and low-power disposable backscatter instrument for atmospheric cloud detection.
• To enable optical detection of clouds from a balloon-carried platform, even during daytime.
• To provide measurements interpretable as equivalent visual range within clouds.

Main Methods:

• Utilized an ultra-bright light emitting diode (LED) as an illumination source and a photodiode detector.
• Employed a lock-in technique to separate the small optical signal from background light fluctuations.
• Integrated the instrument with a conventional meteorological radiosonde for balloon deployment.

Main Results:

• Demonstrated successful optical detection of clouds using scattered LED light.
• Achieved sufficient signal-to-noise ratio for reliable cloud detection, including during daytime.
• The instrument's response was successfully interpreted in terms of equivalent visual range within the cloud.
• The device proved lightweight (150 g) and low-power (~30 mA).

Conclusions:

• The developed disposable backscatter instrument is effective for atmospheric cloud detection from balloon platforms.
• The instrument's design allows for reliable daytime cloud optical measurements.
• Its low power consumption and light weight make it suitable for integration with standard meteorological radiosondes.