Note: A self-calibrating electrometer for atmospheric charge measurements from a balloon platform

Area of Science:

• Atmospheric Science
• Cloud Physics
• Aerosol Science

Background:

• Charged aerosol particles and water droplets are prevalent in the lower atmosphere.
• These charged particles can influence interactions within small cloud droplets.
• Understanding charge distribution is crucial for cloud dynamics and atmospheric electricity.

Purpose of the Study:

• To introduce a novel, small, disposable sensor for measuring electric charge in non-thunderstorm clouds.
• To improve upon previous sensor designs for atmospheric charge measurement.
• To provide a reliable method for in-situ charge detection on balloon platforms.

Main Methods:

• Development of a disposable sensor utilizing a self-calibrating current measurement technique.
• Integration of the sensor onto a free balloon platform alongside a standard meteorological radiosonde.
• Testing the sensor's performance across a temperature range of 5 °C to -60 °C, with stability within 5 fA.

Main Results:

• The sensor accurately measures currents ranging from 2 fA to 15 pA.
• Demonstrated stability of the sensor within 5 fA over a wide temperature range.
• Detected significant charge layers, up to 40 pC m(-3), at the edges of a stratocumulus cloud during a balloon flight.

Conclusions:

• The developed sensor offers a practical and improved method for measuring atmospheric charge in non-thunderstorm clouds.
• The detection of substantial charge layers highlights the importance of charge in stratocumulus cloud formations.
• This technology advances the capability for in-situ atmospheric electricity research.