The Contributions of Photography and Videography to Lightning and Transient Luminous Event (TLE) Research

While lightning strikes the earth tens of times each second and the nation tens of millions of times per year, obtaining detailed visual measurements of a phenomenon that occurs on the scale of micro- and milliseconds has remained a challenge to this day. Photography, since the first still image of a lightning cloud-to-ground strike in 1882, has played a key role in unraveling the complexity of the lightning discharge. Film, motion picture, streak, fish eye, and conventional video cameras have all helped elucidate lightning's complexity. Particularly over the past quarter century, advances in imaging technology have been instrumental in the discovery and understanding of a new class of atmospheric electrical phenomena - transient luminous events (TLEs), a collective term for such phenomena as sprites, blue jets, gigantic jets, halos and elves. Technologies such as low-light CCD cameras, high-speed imaging, and high ISO DSLRs with expanded spectral ranges have been instrumental in revealing the details of TLEs as well as their associated parent lightning discharges. Today, the automated SpriteNet camera network, sensors on research (and soon, operational) satellites, and cameras on the ISS continue to expand our understanding of the meteorological environment conducive to unusual or energetic lightning and TLEs while allowing further exploration of their physics. A new mobile platform for optical measurements, the Lightning Intercept Vehicle (the LIV), is being deployed to obtain high-speed video of sprite parent CGs, especially within 3-D lightning mapping arrays (LMA), with an additional design capability for high resolution imaging of the lightning attachment process at speeds greater than 1 million frames per second. In this review, we will summarize the role of imagery in the discovery and study of sprites, blue jets, gigantic jets, and lightning characteristics such as recoil leaders, continuing currents, self-initiated upward lightning (SIUL) and lightning triggered upward lightning (LTUL).