Analysis and Comparison of Trends in Extreme Temperature Indices in Riyadh City, Kingdom of Saudi Arabia, 1985–2010

Table 1

Extreme temperature indices used in present study (adapted from [29]).

Index	Descriptive name	Definition	Units
Extreme value indices
TXa	Mean TX	Annual mean of monthly mean TX	°C
TNa	Mean TN	Annual mean of monthly mean TN	°C
TXx	Max TX	Annual mean of monthly maximum of TX	°C
TNx	Max TN	Annual mean of monthly maximum of TN	°C
TXn	Min TX	Annual mean of monthly minimum of TX	°C
TNn	Min TN	Annual mean of monthly minimum of TN	°C
DTR	Diurnal temperature range	Annual mean of monthly mean difference between TX and TN	°C
Relative indices
TN10p	Cool nights	Number of days when TN 10th percentile	Days
TX10p	Cool days	Number of days when TX 10th percentile	Days
TN90p	Warm nights	Number of days when TN 90th percentile	Days
TX90p	Warm days	Number of days when TX 90th percentile	Days
Range indices
WSDI	Warm spell duration indicator	Annual count of days with at least 6 consecutive days when TX 90th percentile	Days
CSDI	Cold spell duration indicator	Annual count of days with at least 6 consecutive days when TN 10th percentile	Days

: temperature; Max.: maximum; N: minimum; TN: daily minimum temperature; TX: daily maximum temperature.