Vaisala, Inc.

Ryan K Said

Martin J Murphy

Example methods and systems described herein relate to determining average arrival time of a radio wave emitted by a lightning discharge and/or determining the lobe and/or polarity of the radio wave. The determination of the average arrival time may take a weighted average of arrival times of peaks of the radio wave. The determination of the lobe and/or polarity may depend on an estimated propagation distance, a propagation path profile, and one or more waveform features.

Consistent arrival time measurement and determination of discharge polarity

Systems and methods are disclosed to detect cloud-to-ground (CG) strokes that include and/or are followed by continuing current (CC). For example, earth-based lightning data may be generated for one or more lightning pulses detected in an environmental space using multiple earth-based lightning detection sensors. Space-based lightning data may be received for one or more optical signals detected in the environmental space using one or more space-based lightning detection sensors. It may be determined from the earth-based and space-based lightning data whether a lightning pulse is a CG stroke that includes or is followed by CC. Charge transfer of a CG stroke with CC may be obtained from measurements of electromagnetic fields by an array of electromagnetic field sensors to generate training data. A machine learning model may be trained to relate space-based and/or earth-based lightning data to charge transfer where there is no proximate array of electromagnetic field sensors.

Quantification of charge transfer in continuing current lightning events

A method includes detecting, by a pair sensors located at two locations, a radio wave generated from a lightning discharge occurring; for the pair of sensors, determining propagation paths between the discharge and sensors; repeating the same with a second pair of sensors and another lightning discharge; for each path, determine path vectors defined by an attenuation coefficient vector; constructing a matrix with each row comprising the difference between path vectors from sensor pair measurements from the lightning discharge and including a selection entry based on the identification of the sensors to enable the logarithm of sensor calibration factors to be solved for; constructing another vector, where each entry comprises the difference between the logarithms of the sensor amplitudes from a sensor pair measurement adjusted by a logarithm of an offset; inverting a system of linear equations defined by the matrix to solve for attenuation and sensor calibration factors.

Empirical determination of VLF attenuation factors

Systems and methods are disclosed to detect cloud-to-ground (CG) strokes that include or are followed by continuing current. As an example, earth-based lightning data may be generated for one or more lightning pulses detected in an environmental space using multiple earth-based lightning detection sensors. Space-based lightning data may be received for one or more optical signals detected in the environmental space using one or more space-based lightning detection sensors. It may be determined whether one or more lightning pulses is a CG stroke based on the earth-based lightning data. In response to determining that a given one of the one or more lightning pulses is a CG stroke, it may be determined whether the CG stroke includes or is followed by continuing current based on the space-based lightning data.

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Broomfield, CO, United States of America

Ryan K Said