Note: A self-calibrating wide range electrometer for in-cloud measurements

Area of Science:

• Atmospheric science
• Cloud physics
• Instrumentation

Background:

• Cloud electrification influences weather phenomena and atmospheric processes.
• Accurate in-cloud charge measurements are crucial, requiring instruments with a wide dynamic range.
• Existing electrometers face limitations such as saturation or thermal drift, hindering precise measurements.

Purpose of the Study:

• To develop a novel hybrid electrometer system for accurate in-cloud charge measurements.
• To overcome the dynamic range limitations and thermal sensitivity issues of current instruments.
• To enable new opportunities for studying charge in clouds, dusts, and aerosols.

Main Methods:

• A hybrid system combining linear and logarithmic electrometers was designed.
• The system utilizes the stable performance of the linear electrometer for in situ calibration.
• The hybrid design provides an extended dynamic range of ±50 pA.

Main Results:

• The novel hybrid electrometer system demonstrates an extended dynamic range.
• In situ calibration using the linear electrometer effectively compensates for logarithmic electrometer thermal effects.
• Negligible temperature drift (±4%) was observed in the linear component.

Conclusions:

• The hybrid electrometer system offers a robust solution for measuring a wide spectrum of charge densities in atmospheric conditions.
• This innovation facilitates more accurate and comprehensive studies of cloud electrification and aerosol charging.
• The system's design is suitable for disposable balloon-carried instruments, advancing atmospheric research.