ALOFT Electric Field Sensors
Overview of the EFCM and LIP electric field sensors.
Electric Field Change Meter (EFCM)
The Electric Field Change Meter (EFCM) on the ALOFT package is a two-channel (fast and slow) antenna that measures the derivative of the electric field impulse produced by lightning. The fast channel is designed to isolate the radiative component of the lightning discharge field while the slow channel is optimized to observe the electrostatic field component. The EFCM has multiple sensitivity ranges that are selectable during flight and samples with 16-bit resolution.
Fast Channel
10 MHz sample rate
100 us decay time constant
Slow Channel
1 MHz sample rate
150 ms decay time constant
Lightning Instrument Package (LIP)
The Lightning Instrument Package (LIP) consists of seven rotating vane electric field mills on the ER-2 aircraft to observe electric fields generated by clouds and storms, as well as rapid changes in electric field due to lightning occurrence. LIP measures the vector electric field in the atmosphere and the charge induced on the aircraft using the processing and calibration technique in Mach and Koshak (2007). Properly calibrated on the aircraft, LIP can reliably measure fields lower than 1 V m-1. Effects on the derived vertical electric field due to aircraft charging are generally 5% or less, with a maximum upper error of 10% (Mach et al., 2009). LIP’s role in ALOFT is to characterize the electric field produced in storms that generate gamma-ray glows and TGFs. LIP will also provide valuable context on electricity generation to growing storms prior to their first lightning flash.
More information on LIP can be found here: https://ghrc.nsstc.nasa.gov/home/micro-articles/instrument-lightning-ins... (external link)
PI: Christopher Schultz (external link)
Co-PI: Richard Blakeslee, Monte Bateman, Douglas Mach
References
Mach, D. M., and W. J. Koshak (2007), General matrix inversion technique for the calibration of electric field sensor arrays on aircraft platforms, J. Atmos. And Oceanic Tech., 24, 1576-1587
Mach, D. M., R. J. Blakeslee, M. G. Bateman, and J. C. Bailey (2009), Electric fields, conductivity, and estimated currents from aircraft overflights of electrified clouds, J. Geophys. Res., 114, D10204, doi:10.1029/2008JD011495