Abstract: The disclosure is directed to a method and apparatus for remotely sensing electrical activity and potential for lightning occurrence. The disclosure is particularly directed to the use of such an apparatus and method to detect the electrical alignment of particles in upper levels of electrified storms. Storms are illuminated by radar in one or more orthogonal polarizations and the co-polar and cross-polar returns are correlated coherently and incoherently. The correlation coefficient, or a function thereof, is examined to determine the degree of particle alignment, and therefore the degree of electrification and potential for lightning occurrence. The phase of the correlation computation, in coherent processing, also detects particle alignment, which can be incorporated in the predictive decision. Correlation and phase can be displayed, recorded or, utilized for a prediction or warning.

Abstract: A method is described for determining the return stroke polarity of distant lightning for distances beyond 600 km by detecting the electric field associated with a return stroke of distant lightning, and processing the electric field signal to determine the polarity of the slow tail of the VLF waveform signal associated with the detected electric field. The polarity of the return stroke of distant lightning is determined based upon the polarity of the slow tail portion of the waveform.

Abstract: A method and apparatus for discharging electric charge accumulated on an object tht expels an electrically conductive gas flow, such as a jet engine, a rocket, or a helicopter or aircraft with an internal combustion engine. The system has an electrical shield surrounding a portion of the gas flow, and an electrode for imposing an electric potential in the shielded gas flow. A servo controller measures the accumulated charge at a point on the object and creates a control signal responsive to the rate at which charge is accumulating. The servo controller imposes an electric potential on the electrode, and hence the gas flow, of an amount and polarity determined by the rate and polarity of charge accumulation. In so doing, the electrode accelerates charges of opposite polarity in the conductive gas away from the object, and deaccelerates like charges towards the object, where they tend to cancel accumulated charges, thus discharging the object.

Abstract: Disclosed herein is a method for removing airborne particulates from an aerosol stream by first humidifying said aerosol with steam, and then cooling said aerosol with water to saturation temperature. Thereafter, the saturated aerosol is adiabatically cooled to a supersaturated state and maintained at supersaturation for a time sufficient to permit the growth and removal thereof of said particulates. Further disclosed is an apparatus adapted for practicing the method of the present invention and employing charged droplet scrubbing techniques to remove said particulates.

Abstract: Reflectivity estimates from clouds and other clutter targets normally reqe an averaging of a large number of independent radar pulse samples. If the radar generates noise pulses of a predetermined bandwidth and pulse length, a large number of returns can be derived and, when averaged over the full length of the pulse, the returns provide the desired reflectivity estimate. Considering a noise source whose spectrum in the frequency domain can be represented by a rectangular function of width .beta. (bandwidth), the properties of this function are such that the time (.tau.) at which it first becomes zero is related to .beta. by .tau.=1/.beta.. Time .tau. is the correlation time. If the pulse length T is made relatively long compared to the correlation time, it becomes possible to average or integrate within the pulse length T since the number of uncorrelated noise configurations is T/.tau.=.beta.T. For a noise pulse of one microsecond long (T) and a bandwidth (.beta.