Instrument Acronym:
Instrument Measurements:
a) Trace Gas
b) Cloud Physics/Aerosol
c) Radiation/Optical/Electrical
With a properly located pair of electric field meters the ambient
electric field can be measured, for example a pair of mill mounting
opposite one another on the top and bottom of the fuselage gives a
measure of the vertical component of the environmetal electric field.
The pair of field mills will also give a measure of charge on the
aircraft. Each mill responds to both the ambient field and also the
field caused by charge on the aircraft. By subtracting the signals
from the two mills one can obtain the ambient field, whereas adding
the signals gives a measured of the charge on the aircraft.
d) Additional Capabilities
Resource Person/Developer:
Name: Jim Dye
Affiliation: NCAR/MMM/ATD
Phone: (303) 497-8944
Email: dye@ucar.edu
Principle of Measurement:
Each mill measures the charge induced on a plate, which is
alternatively exposed and shielded from the local field. Knowledge of
how the aircraft shape distorts and enhances the local field measured
by the insturment is an integral and critical part of a valid
measurement.
In situ/Remote/Flux Measurement:
In situ measurement
Field projects in which the instrument has been used:
Studies in New Mexico with the King Air and with the sailplane during
CAPE, S2D2. The sailplane has both fuselage mills as well as a
special cylinrical field mill built by Dr. Bill Winn and Dan Jones of
New Mexico Tech
Aircraft Platform:
none presently except for the Explorer Sailplane
Inlet Configuration/Location:
Calibration/Cross Calibration:
Has been done for individual mills only by applying
a known electric field.
Operator Requirements:
A research instrument required considerabel attention
for analysis, but relatively easy in operational use
Data Collection:
self
Post-flight Data Validation, Processing, Hours per Flight Hour etc.
Physical Characteristics:
Dimensions: roughly 5" x 9" high (cylindrical)
Weight: about 5 lbs
Power: 28V on the King Air
Other:
Response Time:
less than a second
Detection Limits:
Nominally 200 V/meter to 200 kV/meter ambient field.
Accuracy:
dependent upon the platform and other considerations.
In-cloud measurement are much more difficult than
clear air.
Precision:
Limitations (such as altitude, airspeed, etc.)