Degree Heating Week
"Degree Heating Week (DHW) is a measure of accumulated heat stress over the last 12 weeks and above a physiological temperature stress threshold relevant to corals. It is important to note that this metric of heat-stress has limitations as coral sensitivity to heat stress is highly variable among genera, with some groups showing much higher heat-tolerance (e.g. Goniastrea spp.) than others (e.g. Acropora spp.)" (Kayanne 2017)
Sources
Kayanne, Hajime. 2017. “Validation of Degree Heating Weeks as a Coral Bleaching Index in the Northwestern Pacific.” Coral Reefs 36 (1): 63–70. https://doi.org/10.1007/s00338-016-1524-y.