Lambdasonde

LambdaSonde is a compact, autonomous atmospheric profiling instrument designed for deployment on radiosondes, weather balloons, or fixed-mount platforms. It extends conventional sounding packages by incorporating lambda-resolved optical sensing, enabling simultaneous measurement of meteorological state variables and wavelength-dependent atmospheric properties. The primary goal is to provide data that support investigations into aerosol optical depth, gas absorption features, and cloud optical thickness alongside standard temperature, humidity, pressure, and wind profiles.

Payload and sensors: core sensors measure temperature, relative humidity, and atmospheric pressure; a GPS receiver provides position and wind data; an onboard microprocessor handles timing and data integrity. The optical subsystem uses a compact spectrometer or an array of narrowband photodiodes to sample transmission and scattering in selected wavelength bands (lambda). Measurements are synchronized with the meteorological sensors and stored as time-stamped records, with optional real-time downlink over UHF radio.

Operation and performance: power is supplied by rechargeable batteries; typical missions last several hours. The altitude range follows standard radiosonde envelopes, with operation up to stratospheric levels under appropriate conditions. The enclosure is designed to withstand low temperatures and pressure changes found at high altitudes; parachute release on termination is implemented for safe descent.

Applications: used in weather and climate research, air-quality studies, and validation of satellite retrievals; in education and citizen-science contexts as a low-cost platform for spectral measurements.

Development and status: LambdaSonde emerged from research groups focusing on cost-effective spectral sensing for atmospheric research; prototypes were demonstrated in field trials in the early 2020s; it remains an active project with variations and open hardware initiatives.