Accumulated cyclone energy

Accumulated cyclone energy (ACE) is a measure used by the National Oceanic and Atmospheric Administration (NOAA) to show the activity of each tropical cyclones and entire tropical cyclone seasons, particularly the Atlantic hurricane seasons. It uses an estimation of the energy used by a tropical system over its lifetime and is calculated in every six hours.^[1]

1. ↑ Bell, Gerald D., Halpert, Michael S., Schnell, Russell C., Higgins, R. Wayne, Lawrimore, Jay, Kousky, Vernon E., Tinker, Richard, Thiaw, Wasila, Chelliah, Muthuvel, Artusa, Anthony. Climate Assessment for 1999. Bulletin of the American Meteorological Society 2000 81: 1328-1328^{[permanent dead link]}