88th Annual Meeting (20-24 January 2008)

Wednesday, 23 January 2008
Operational evaluation of lightning precursors from a network of field meters at Dugway Proving Ground
Exhibit Hall B (Ernest N. Morial Convention Center)
Margaret B. Kimball, U.S Army, Dugway Proving Ground, Dugway, UT; and F. W. Gallagher III
Poster PDF (1.8 MB)
Evaluating the potential for a thunderstorm to produce lightning is a critical forecast skill in many operational settings. In support of this mission, the U.S. Army Dugway Proving Ground has installed a network of 28 field mill stations with an areal coverage of approximately 2000 square kilometers. This network of field meters, spaced approximately 5-10 km apart, provides the ability not only to monitor changes in the vertical component of the electric field at a single station, but also to examine the spatial variability of the electric field in response to the passage of electrified clouds and other phenomena.

Changes in the vertical component of the electric field as measured at the surface by field meters have been previously correlated to lightning strikes; however, the use of an analysis of the spatial variability of the electric field as a predictor of cloud-to-ground lightning (and eventually its cessation) is virtually non-existent on an operational basis and will be the focus of this study.

First, this paper discusses the creation of electric field analyses in real time. Barnes analysis and temporal averaging are employed to balance the high temporal resolution necessary to resolve lightning events with the computational restraints of a real-time product. Next, case studies of the passage of both lightning producing and non-lightning producing storms are examined to assess the correlation between the electric field structure and subsequent lightning strikes. The spatial variability of the magnitude, gradient, derivative, and Laplacian of electric field are examined as potential precursors. Finally, the results of the case study are applied to other cases for verification and comparison. The ultimate goal of the project is to increase lead time for lightning forecasts to allow more personnel to take shelter, while simultaneously eliminating down time due to non-lightning producing storms.

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