HR: 09:30h
AN: AE51A-06    [PDF]
TI: Observations of Thunderstorm Effects on Middle-Atmosphere Ionizable Constituents
AU: * Croskey, C L
EM: CCroskey@psu.edu
AF: Communications and Space Sciences Laboratory, Dept. of Electrical Engineering The Pennsylvania State University 303 Electrical Engineering East, University Park, PA 16802 United States
AU: Mitchell, J D
EM: jdm4@psu.edu
AF: Communications and Space Sciences Laboratory, Dept. of Electrical Engineering The Pennsylvania State University 303 Electrical Engineering East, University Park, PA 16802 United States
AU: Friedrich, M
EM: Friedrich@inw.tu-graz.ac.at
AF: Dept. of Communications and Wave Propagation, Technical University of Graz, Graz, A-8010 Australia
AU: Meriwether, J W
EM: john.meriwether@ces.clemson.edu
AF: Dept. of Physics and Astronomy, Clemson University 208 Kinard Laboratory, Clemson, SC 29634 United States
AB: A coordinated rocket and ground-based program to investigate the effects of nearby thunderstorm activity on middle-atmosphere ionizable constituents was conducted at Wallops Island, VA. The first rocket payload was launched in darkness at 0632 UT on May 10, 2002. On the previous evening a significant weather front passed over the Appalachian mountains in Virginia approximately seven and a half hours before the time of the rocket launch. The front continued eastward to the Eastern Shore of Virginia and passed the rocket apogee location about three hours before the launch. A ground-based optical imager provided by Clemson University observed spherical wave structure in both the 557.7 nm and OH images after the front had passed over the launch range. An identical payload was launched at 0626 UT on May 16, 2002. There was no tropospheric convective activity in the area at the time of this launch or during the entire preceding evening. No obvious spherical wave structure was seen in the imager data during this evening. Four Gerdien condenser instruments, which measured ion conductivity, mobility, and concentration, were located at the front of each payload. Positioned in the center electrode of each Gerdien condenser was an RF-excited UV source. A different rare gas and window combination used with each lamp provided the sources for investigating the ionization/photodetachment properties of the aerosols. The lamp wavelengths ranged from 123.6 nm (10 eV) to 365 nm (3.4 eV). The payload also included a fixed-bias Langmuir probe for observation of both the background and lamp-induced electron concentrations. Absolute calibration of the Langmuir data was provided by an on-board Faraday radio-wave propagation experiment. While the main focus of the experiment was to identify thunderstorm-associated effects on mesospheric particles, the data during the disturbed evening additionally showed a significant change in the concentration of gas-phase ions (presumably, NO+) produced by the 123.6-nm UV source. This difference in response between the two evenings is thought to be related to changes in the neutral density temperature, produced either by gravity waves or electrostatic heating from the thunderstorm activity.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0340 Middle atmosphere--composition and chemistry
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting