Measuring Heatwaves and Their Impacts, Table 1 (continued)
Index
Description
Max.
temperature
Min.
temperature
Relative
humidity Other
Intensity
output
Reference
Heatwave
frequency
(HWF90)
The average
heat wave
frequency,
where
heatwaves are
defined as
6 consecutive
days exceeding
the 90th
percentile of the
historical
control period
(1961–1990)
X
Fischer and
Schär [23]
Heatwave
number
(HWN90)
The annual
number of heat
waves, where
heatwaves are
defined as
6 consecutive
days exceeding
the 90th
percentile of the
historical
control period
(1961–1990)
X
Fischer and
Schär [23]
Heatwave
amplitude
(HWA90)
The
“amplitude” or
average peak
temperature of
the hottest
heatwave per
summer
X
Fischer and
Schär [23]
Heatwave
Duration
(HWD90)
The average
duration of the
longest
heatwave per
summer
X
Fischer and
Schär [23]
Combined hot
days and
tropical nights
(CHT)
The average
number of days
with both
maximum
temperatures
exceeding 35
C
and minimum
temperature
exceeding 20
C
X
Fischer and
Schär [23]
Apparent
temperature
(T a _105F)
The average
number of days
with a
maximum
humiditycorrected
apparent
temperature
exceeding
X
X
Steadman
[24],
Steadman
[25]
(continued)
Measuring Heatwaves and Their Impacts
459