Abstract: A method to mitigate radio frequency interference (RFI) in weather radar data may include computing p norms of radials of weather radar data to construct an p norm profile of the weather radar data as a function of azimuth angle. The weather radar data may include Level 2 or higher weather radar data in polar format. The method may include determining that a given radial in the weather radar data is an RFI radial based on the p norm profile of the weather radar data. The method may include displaying an image from the weather radar data in which at least one of: the RFI radial is identified in the image as including RFI; or the RFI radial is omitted from the image.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Systems and methods are disclosed to determine the severity of a thunderstorm and/or track the path of a thunderstorm. For instance, multiple thunderstorms may be tracked by assigning detected lightning flashes to thunderstorm objects based on a number of previous lightning flashes assigned to each of the thunderstorm objects and a distance between each of the lightning flashes and each of the thunderstorm objects. In addition, an updated position may be determined for each of the thunderstorm objects based on positions and ages of lightning flashes assigned to each of the thunderstorm objects. The severity of a given thunderstorm may be determined based on lightning rates, types, and/or polarities of lightning flashes and/or lightning pulses of the thunderstorm object.

Abstract: 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.

Abstract: A method to generate data to geolocate lightning pulses may include detecting in an environment EMF generated from the lightning pulses. The method may include producing lightning-EMF from the detected EMF where the lightning-EMF may represent the EMF generated from the lightning pulses. The method may include extracting a lightning-waveform-feature set from the lightning-EMF data, including extracting one or more waveform features for each of the lightning pulses from the lightning-EMF data. The method may also include transmitting the extracted lightning-waveform-feature set to a server to perform time alignment on multiple extracted lightning-waveform-feature sets received from multiple lightning-detection sensors and to geolocate the lightning pulses based on the time-aligned extracted lightning-waveform-feature sets.

Abstract: Systems and methods are disclosed to label data collected by one instrument based on data collected by another instrument, train a computer learning model with the labeled data, and then use the trained computer learning model to estimate a condition from new unlabeled data. For example, weather-related pavement conditions may be estimated from camera images according to such systems and methods. Systems and methods are also disclosed to estimate road weather safety or hazard conditions using two different types of pavement conditions, such as road state and friction or grip coefficient, estimated from unlabeled camera images.

Abstract: Systems and methods are disclosed for forecasting lightning activity. Such a method may include obtaining radar reflectivity data from a radar detection device for multiple altitudes over an environmental region for a past period of time, and dividing the reflectivity data into multiple sub-regions within the region. The method may also include obtaining lightning discharge data for the environmental region from a lightning discharge detecting device for a past period of time, and establishing a customizable mathematical operator based on the radar reflectivity data and the lightning discharge data. The method may additionally include receiving forecast radar data for at least one of the sub-region for a future time period, and forecasting a probability of lightning strikes in at least one of the sub-regions based on applying the customizable mathematical operator to the forecast radar data.

Abstract: Systems and methods are disclosed to determine an unambiguous radial velocity for weather phenomena using weather radar that is not limited by the Doppler Dilemma. Some embodiments include transmitting a complex waveform and using the returned electromagnetic signal to determine the unambiguous radial velocity.

Abstract: A system for heating the sound-reflective mirror surface of a phased array monostatic sodar apparatus. The system has a heat source located at a position that is spaced from the mirror, a control system that controls the operation of the heat source, a working fluid that is heated by the heat source and used to transfer heat from the source to the mirror, and a delivery system that constrains the heated working fluid and delivers it from the heat source to the mirror.

Abstract: A transducer includes a base, a horn, and a central element. The horn includes a first end coupled to the base and a second end extending from the base and having a perimeter that defines a substantially planar face of the transducer, the horn defining a horn length along a horn surface between the first end and the second end of the horn. The central element includes a first end coupled to the base and a second end extending from the base along a longitudinal axis of the horn, the central element defining a central element length along a central element surface between the first end and the second end of the central element, the central element length being substantially equal to the horn length.

Abstract: In one embodiment, a wind power ramp event nowcasting system includes a wind condition analyzer for detecting a wind power ramp signal; a sensor array, situated in an area relative to a wind farm, the sensor array providing data to the wind condition analyzer; a mesoscale numerical model; a neural network pattern recognizer; and a statistical forecast model, wherein the statistical model receives input from the wind condition analyzer, the mesoscale numerical model, and the neural network pattern recognizer; and the statistical forecast model outputs a time and duration for the wind power ramp event (WPRE) for the wind farm.

Abstract: In one embodiment, a wind power ramp event nowcasting system includes a wind condition analyzer for detecting a wind power ramp signal; a sensor array, situated in an area relative to a wind farm, the sensor array providing data to the wind condition analyzer; a mesoscale numerical model; a neural network pattern recognizer; and a statistical forecast model, wherein the statistical model receives input from the wind condition analyzer, the mesoscale numerical model, and the neural network pattern recognizer; and the statistical forecast model outputs a time and duration for the wind power ramp event (WPRE) for the wind farm.

Abstract: Systems and methods that adapt to the weather and clutter in a weather radar signal and apply a frequency domain approach that uses a Gaussian clutter model to remove ground clutter over a variable number of spectral components that is dependent on the assumed clutter width, signal power, Nyquist interval and number of samples. A Gaussian weather model is used to iteratively interpolate over the components that have been removed, if any, thus restoring any overlapped weather spectrum with minimal bias caused by the clutter filter. The system uses a DFT approach. In one embodiment, the process is first performed with a Hamming window and then, based on the outcome, the Hamming results are kept or a portion of the process is repeated with a different window. Thus, proper windows are utilized to minimize the negative impact of more aggressive windows.

Abstract: A system and method for detecting meteorological phenomena by transmitting a sequence of pulses, each pulse having a long range section and a short range section. Echoes based on the sequence of pulses are received. A filter is applied to the echoes to create an ambiguity signal that allows simultaneous detection of targets for a range from range zero up to and including a maximum unambiguous range.

Abstract: A lightning detection system provides an estimated location of a lightning stroke. The system includes sensors, and an analyzer. Each sensor provides messages having sensor identification, an amplitude responsive to the lightning stroke, and a time of detecting the lightning stroke. The analyzer applies time corrections and amplitude corrections to improve the accuracy of determining the location of the lightning stroke. Time adjustments and amplitude adjustments for the time and amplitude corrections are recalled from a matrix accessed according to a suggested or estimated location. The matrix may be organized by coordinates of longitude and latitude.