Table 1.

Summary of related definitions for compound drought and heat event.

Event	Definition
Drought day	Light drought : − 1.0 < MCI <  − 0.5 Moderate drought: − 1.5 < MCI ≤  − 1.0 Severe drought: − 2.0 < MCI ≤  − 1.5 Extreme drought: MCI ≤  − 2.0
Heat day	Tmax > Tmax95 Tmax95 refer to 95 percentile of daily maximum air temperature in the warm season of 1961–1990
Compound drought and heat event (CDHE)	MCI ≤  − 0.5 and Tmax ≥ Tmax95
K-day compound drought and heat event	a K-day CDHE is defined if the CDHE persists for K days, then the CDHE terminates when MCI > − 0.5 or Tmax < Tmax95
Non-persistent compound drought and heat event	CDHE with a duration of 1- and 2-days
Persistent compound drought and heat event	CDHE with a duration of longer than 2 days