Monitoring Parameters

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ELECTROMAGNETIC RADIATION AND SEVERE WEATHER

Building An Electrostatic and Magnetic Pulse Monitor

by Richard W. Fergus

Start • Monitoring Parameters • Analysis Procedures • Pattern Observations • Hardware • Monitor Programs • Forecast • Sources

MONITORING PARAMETERS

Three parameters (pulse shape, pulse polarity, and relative timing) of the electromagnetic radiation are measured with reference to the direction-of-arrival. These measurements are used to observe changes in the spectral distribution rather than the exact magnitude of the parameter. In general, signal amplitude is disregarded.

A crude measurement of electrostatic pulse polarity/shape (width) component is made by noting the polarity of the first signal excursion and the time (width) to the next excursion of the opposite polarity. These factors are accumulated with and referenced to direction-of-arrival.

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The relative timing between a series of events has been the primary monitoring parameter for many years. For this data, each series of three events that occur from the same direction in less than 1 s is sorted into one of two categories. Either the time between the first and second event is greater or less than the time between the second and third event. In a long series of events, each event will contribute to more than one comparison. Each series is also counted as a burst.

These accumulations are referenced to the signal direction-of-arrival (120 segments or 3�/segment). Periodically, (usually each 5 min.), the accumulations are analyzed and separated into categories of generated total activity, burst activity, percentage of positive events, percentages of long pulses (width), and a timing factor that is the ratio of the greater-than/less-than relative timing accumulators.

These summations are further reduced to peak activity descriptors (e.g., bands of activity concentration with reference to direction-of-arrival). Each peak descriptor includes direction, activity level (events per time period), timing factor, positive event percentage, and long pulse-width percentages. This data is the basis for the pattern analysis.

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