HR: 0800h
AN: AE31A-0027    [Abstracts]
TI: Correlation between lightning flash count and local meteorological parameters
AU: * Walden-Newman, W W
EM: wwaldenn@nmt.edu
AF: Physics Dept, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, United States
AU: Sonnenfeld, R G
EM: rsonnenf@nmt.edu
AF: Physics Dept, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, United States
AU: Stock, M
EM: george@nmt.edu
AF: Physics Dept, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, United States
AU: Shao, X
EM: xshao@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, United States
AB: It is interesting to know the likelihood of an electrified storm in the afternoon or evening based on morning measurements of meteorological parameters. Soundings are generally used to obtain such measurements, but not all locations are near to a National Weather Service sounding site. Thus, a statistical study was conducted comparing lightning flash counts with all of the following: mixing ratio (MR) of water to air, temperature, winds, and convective available potential energy (CAPE). Meteorological parameters were compared with lightning flash counts on the ground and at pressure alititudes of 500 hPa at 1200 and 0000 UTC. The study covered an 85-day period in the summer of 2005, with lightning data from the Los Alamos Sferic Array (LASA), and meteorological data from upper-air balloon soundings at NWS stations. In a log-log plot of mixing ratio at ground level and lightning flash count, we found a correlation coefficient r=+0.7 in the southwestern United States. Southwestern summer days with MR greater than 7-8 g/kg at 1200 UTC frequently produce lightning. In Oklahoma, we found r=- 0.5 correlation in a log-log plot of dry-bulb temperature (at 500 hPa) vs. flash count, with a decrease of this temperature corresponding to an increase in the flash count. The strongest correlation for Pennsylvania was r=+0.5 between CAPE and lightning. We also verified at some sites that the correlation was strongest for lightning confined to within 200 km of the sounding site, strengthening our confidence that the measurements of the local air mass were revealing a causal relationship to lightning activity. We will discuss why the best correlating parameters varied from region to region in the context of the theory of colliding ice and riming graupel as the dominant source of electrification in thunderstorms.
DE: 3304 Atmospheric electricity
DE: 3314 Convective processes
DE: 3324 Lightning
DE: 3354 Precipitation (1854)
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting