Red sprites, upward lightning, and VLF perturbations
In the last decade there has been a great deal of interest in the detection and understanding of phenomena occurring above active thunderstorms. The discovery of the optical phenomena now termed “red sprites” is discussed, along with the properties that have been experimentally determined. Areas of disagreement between experimentalists are pointed out. Other optical and electromagnetic phenomena associated with red sprites are presented. These include blue jets, transionospheric pulse pairs, and gamma ray flashes. Particular attention is given to the work on perturbations on very low frequency radio wave transmissions (“VLF sprites”), which has provided estimates of the electrical properties of sprites. Research into activity above thunderstorms will continue to lead to a greater understanding of the coupling between thunderstorms in the troposphere to the stratosphere, mesosphere, ionosphere, and beyond.