Analysing lightning data from two spatially separate magnetic direction finders
Date
2009-03-23T11:24:05Z
Authors
Rice, David Andrew
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Abstract
Two lightning detectors, of the magnetic direction finder type, form part of a two station
system for determining the position of lightning strikes. The detectors are on a baseline
of approximately 600 m, and the ultimate aim of the system is to accurately detect and
map lightning within a radius of 30 km. Although no real time capability is present, the
archive data collected from each separate station is used to find the offset errors in the
azimuthal orientation, as well as in time (using processes described in Appendix A). The
relative offset errors are determined by shifting the time and azimuthal information for one
station’s data and calculating the maximum possible matching records (within certain time
and azimuth criteria) for each incremental shift. An analysis of the peaks in total matching
records, when plotted against the relevant shift increments, is performed in order to obtain
the values of the offset errors. Between the two individual stations, the relative offset in
orientation is found to be 24.5 degrees, and in time to be 0.001305 days (112.75 seconds). The
individual stations, as well as the triangulated data calculated from matching records, can
also be calibrated using data from the South African Weather Service Lightning Detection
Network (SAWSLDN). Individual station calibration indicated an offset of +6.4 degrees and
0.00575 days (496.8 seconds) for Station 1, with the offsets for Station 2 determined as +29.4
degrees and −0.000105 days (9.07 seconds). Comparison of triangulated data to SAWSLDN
data yields unexpected results with regard to resultant shifts, which may point to an error or
anomaly in the triangulation calculations. A detailed analysis of the storm data is contained
in Appendix B of the dissertation.
Description
Keywords
Lightning Lightning location system Magnetic direction finder