the season's activity was reflected with a very high accumulated cyclone energy (ace) rating of 228, the fifth highest value on record, and far above the 1981–2010 median of 92. broadly speaking, ace is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. therefore, a storm with a longer duration or stronger intensity, such as felix, luis, opal, or roxanne will have high values of ace. it is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of 39 mph (63 km/h). accordingly, tropical depressions are not included here. after the storm has dissipated, typically after the end of the season, the nhc reexamines the data, and produces a final report on each storm. these revisions can lead to a revised ace total either upward or downward compared to the operational value.