Multiparameter Investigation of Significant Lightning Producing Storms in Northeastern Colorado
Abstract
We present a regional, summer season, climatology of cloud to ground (CG) lightning immediately east of the central Rocky mountains from 1996-98 using data from the National Lightning Detection Network (NLDN). We document the spatial and temporal variations of summer season CG lightning activity within the region. Our examination focused on describing how CG lightning characteristics (multiplicity and peak current) for each polarity (positive and negative) changed as the percentage of positive CG lightning changed. Specifically, we found that as the positive CG fraction within a storm increased, the average positive (negative) peak current increased (decreased). Similarly, our findings revealed that increases in positive CG fraction were also associated with small increase in positive CG multiplicity and more significant decreases in negative CG multiplicity values. Additionally, we examined the co-evolving microphysical and electrical characteristics of four significant lightning producing storms in northeastern Colorado using the CSU-CHILL multiparameter radar and cloud to ground (CG) lightning data. Using the multiparameter variables of Z(sub h), Z(sub dr), P(sub hv)(0), LDR and K(sub dp), emphasis was placed on determining the three-dimensional distribution of various hydrometeor types in these storms (especially during periods of electrical transition from one CG polarity to another), as well as estimates of rain and hail rates. Our goal in examining these cases was to try and determine the mechanism by which positive ground flashes in mature thunderstorms dominate over negative ground flashes. Specifically, we investigated the following hypothesis: (1) the tilted dipole hypothesis, (2) the enhanced lower positive charge hypothesis, and (3) the precipitation unshielding hypothesis.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 02, 1999
- Accession Number
- ADA366293
Entities
People
- Michael L. Gauthier
Organizations
- Colorado State University